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INTRODUCTION

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

The idiopathic inflammatory myopathies, including adult and juvenile dermatomyositis (DM), polymyositis (PM), and inclusion body myositis (IBM), are rare systemic autoimmune diseases that are characterized by chronic proximal muscle inflammation and weakness. In previous decades, there were few commonly used outcome measures in myositis, and those outcome measures were not validated. Therefore, in the past the assessment of outcomes in therapeutic trials was focused on nonstandardized measurement of muscle strength and function only.

Over the last decade, however, 2 international collaborative groups, the International Myositis Assessment and Clinical Studies Group (IMACS) and the Paediatric Rheumatology International Trials Organisation (PRINTO), have defined consensus core set measures to assess myositis disease activity and damage in adults and children and have begun to validate and standardize these measures (1, 2). IMACS and PRINTO have also developed preliminary definitions of improvement that can be used as outcomes for therapeutic trials. These response criteria combine the core set activity measures to determine clinically meaningful improvement (3, 4). Our section on myositis assessment focuses first on these core set measures of disease activity, quality of life (which is part of the PRINTO core set of activity, but a separate assessment domain for IMACS), and disease damage. To date, most of the validation data available for these core set measures are in patients with juvenile DM, with more limited validation in adult patients with DM or PM. Despite these efforts, there are still important gaps in the validation of these core set measures, and no validation studies have yet been performed in patients with IBM, although they are now being used frequently in myositis therapeutic trials.

We end this article with tools that have been used primarily in research studies and a few therapeutic trials that have some supporting validation in certain subgroups of patients with myositis. These tools are primarily organ-specific measures, including strength and functional assessments and cutaneous assessment tools. Quantitative muscle testing and the IBM Functional Rating Scale are the most commonly used instruments to assess patients with IBM, and although they have little supporting validation in myositis, quantitative muscle testing has been well validated in other myopathies and has been used frequently as an end point in therapeutic trials for IBM.

Although the methods for the assessment of patients with myositis have been limited in their scope, great strides have been made in the last decade in the development of new partially validated tools and international multidisciplinary consensus in using these measures that should enhance our understanding of the diverse effects of myositis on many organ systems and the development of new therapies.

PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

An overall rating of the disease activity related to myositis, defined as potentially reversible pathology or physiology resulting from the underlying disease process (1).

Content.

The physician global assessment of disease activity is to be judged by the physician based on all of the information available at the time of the evaluation, including the subject's appearance, medical history, physical examination, laboratory testing, and prescribed medical therapy. Adult patients or parents of children with myositis completing the patient/parent assessments are asked to take into account all of the active inflammation in their own or their child's muscles, skin, joints, intestines, heart, lungs, or other parts of the body that can improve with treatment. Patients over 10 years of age might also be able to complete a global activity assessment independent of their parents' ratings (5). The global disease activity score is recorded on a 10-cm visual analog scale (VAS) that is often anchored at the end points and middle. For patients and parents, a smiley face is often included at the 0-cm anchor and a sad face at the 10-cm anchor to improve understanding of the scale. A 5-point Likert scale can also be used as an alternative to the VAS.

Number of items.

1 item, either a VAS or a Likert scale rating.

Response options/scale.

For the VAS rating, a score of 0–10 (down to 1 decimal place) is used, and for the Likert scale, a grade of 0 (no disease activity), 1 (mild disease activity), 2 (moderate disease activity), 3 (severe disease activity), or 4 (extremely severe disease activity) is used. The 10-cm VAS may have better precision, sensitivity, and specificity, but the 2 scales correlate highly (5).

Recall period for items.

Scoring of the global disease activity requires that the activity be assessed at present, although a recall period of up to 2–4 weeks for the components of global disease activity is acceptable for stable patients who are assessed less frequently.

Endorsements.

The physician global disease activity has been included as a core set activity measure for patients with adult and juvenile polymyositis (PM), dermatomyositis (DM), and inclusion body myositis (IBM) by the International Myositis Assessment and Clinical Studies Group (IMACS) (5) and as a core set activity measure for juvenile DM by the American College of Rheumatology/Paediatric Rheumatology International Trials Organisation/European League Against Rheumatism (2). These measures are also part of the preliminary response criteria for adult and juvenile DM and PM (4, 6).

Examples of use.

This score is used in myositis therapeutic trials and is now part of the criteria for the preliminary definition of improvement in myositis (3) and natural history studies, particularly those validating new myositis assessment tools (2, 7). Physician and patient/parent global activity assessments are also used as part of the preliminary response criteria for adult and juvenile DM and PM (3, 4).

Practical Application

How to obtain.

The physician and patient global activity assessment is available in publications using this as an assessment tool, free of charge (5). The IMACS web site (http://www.niehs.nih.gov/research/resources/collab/imacs/diseaseactivity.cfm) also hosts copies of these tools, including the grading scales and detailed instructions, along with example cases and sample ratings as training materials for physicians.

Method of administration.

The physician global assessment is completed by the physician assessing the patient and includes factors in the subject's appearance, medical history, physical examination, laboratory testing, and physician's resultant medical therapy. The adult (or teenage) patient or parent of a juvenile patient completes the patient or parent global activity assessment during the clinic or study visit.

Scoring.

A single score is derived by measuring the distance the vertical line is from the left-hand side of the horizontal VAS. The length of the VAS should also be measured, so that the score can be adjusted to a denominator of 10 cm. The Likert scale also results in a single score. Scoring takes <1 minute and is done by hand.

Score interpretation.

Zero represents inactive disease, and higher scores represent more severe disease activity. From a study of 115 juvenile patients with idiopathic inflammatory myopathy (IIM) assessed by pediatric rheumatologists at baseline and at 4–6- and 7–9-month followup evaluations, a Likert scale score of 0 (inactive disease) corresponds to a VAS rating of 0.1 cm (95% confidence interval [95% CI] 0.0–0.2), a Likert scale rating of 1 (mild activity) corresponds to a VAS rating of 1.5 cm (95% CI 1.3–1.6), a Likert scale rating of 2 (moderate activity) corresponds to a VAS rating of 4.8 cm (95% CI 4.4–5.2), a Likert scale rating of 3 (severe activity) corresponds to a VAS rating of 7.6 cm (95% CI 7.0–8.2), and a Likert scale rating of 4 (extremely severe activity) corresponds to a VAS rating of 9.2 cm (95% CI 7.9–10.4) (5).

Respondent burden.

The time to complete a global activity assessment is <1 minute.

Administrative burden.

The time to complete the physician global activity assessment is <1 minute, but this requires integration with other assessment measures to derive an overall impression.

Translations/adaptations.

The parent global activity has been used internationally in the native languages of the patients (2, 8). Physician global activity has been studied and used in all subgroups of patients with myositis, including adult and juvenile PM, DM, and IBM. Patient or parent global activity has been used in juvenile and adult DM and PM patients. Global activity assessments have also been used in a number of other systemic rheumatic diseases.

Psychometric Information

Method of development.

Physician and patient global activity assessments were first used in the assessment of and as core set activity measures and part of the response criteria for other systemic rheumatic diseases, including rheumatoid arthritis and juvenile idiopathic arthritis. They were then adopted and studied in myositis.

Acceptability.

Missing data are not common, and floor and ceiling effects are not common. There can be measurement error if physicians and patients/parents do not look at their previous ratings as part of the determination of the current rating. Although the rating is based on a collection of objective data, it is somewhat subjective and based on the experience of the rater.

Reliability.
Internal consistency.

In terms of internal reliability, Spearman's correlation was excellent (Spearman's r = 0.89) for the correlation of the VAS to the Likert scale for physician global disease activity, and the intraclass correlation coefficient was 0.85 (P < 0.0001) (5).

Test–retest reliability.

Not available.

Interrater reliability.

In a study of pediatric rheumatologists assessing paper cases of juvenile DM, the κ coefficient for agreement in the Likert scale ratings of global disease activity was 0.88, and Cronbach's α was 0.99 (5). Physicians and patients or parents had relatively poor agreement between their ratings (weighted κ coefficients 0.33–0.34), whereas parents and teenage patients had relatively good interrater reliability (weighted κ coefficient 0.84) in a juvenile IIM natural history study (5).

Validity.
Content validity.

A group of pediatric rheumatologists reached consensus on 17 clinical parameters that they considered very or extremely important in the determination of juvenile DM global disease activity: 3 clinical parameters that were moderately important in their formulation of global disease activity and 9 variables that were unimportant to their rating of global disease activity (5).

Construct validity.

Most studies validating other measures of disease activity have examined the construct validity of physician global activity with the measure whose validation was being tested, and those studies will be discussed below under each of the other measures. For adult PM/DM patients who were screened for therapeutic trials for refractory disease, physician global activity correlated best with serum muscle enzyme levels (Spearman's r = 0.6–0.7), whereas for juvenile IIM, physician global activity correlated best with extramuscular activity, muscle strength, and physical function assessed by the Childhood Myositis Assessment Scale (CMAS) and Childhood Health Assessment Questionnaire (C-HAQ; Spearman's r = 0.6–0.7) (8). Physicians' and parents' or patients' global activity score correlated moderately (Spearman's r = 0.37–0.63), whereas parents' and older juvenile patients' ratings correlated moderately to highly (Spearman's r = 0.57–0.84) in juvenile IIM patients (5). In a study of juvenile DM patients, the correlation of physician and parent global disease activity was moderate (Spearman's r = 0.57) (2). Parent global activity also correlated moderately with other core set measures of disease activity, including the CMAS, C-HAQ, Disease Activity Score, and physical summary score of the Childhood Health Questionnaire (Spearman's r = 0.42–0.65) (2).

Criterion validity.

There is no gold standard upon which to assess criterion validity. Sometimes the physician global activity is used to assess criterion validity in studies validating other measures.

Ability to detect change.

In a juvenile IIM natural history study of patients, the standardized response mean (SRM) for physician global activity was −0.71 for the Likert scale and −0.62 for the VAS at 4-month followup, and after 8 months was −0.58 for both scales. The SRM for parent global activity (−0.54) was similar to the physician global activity after 8 months (5).

For juvenile DM patients who were close to diagnosis or in need of new therapy, the SRM at 6-month followup was 1.6 (95% CI 1.4–1.8) for physician global activity and was 1.2 (95% CI 1.0–1.4) for parent global activity, both assessed on the VAS (2). Both physician and parent global activity ratings had good ability to discriminate between patients who improved and those who did not improve by physician or parent ratings of responses to therapy (2).

For treatment-refractory adult PM/DM patients enrolled in trials of cytotoxic agents, the overall SRM was −0.51, but was −1.5 for the group of patients who met criteria for response.

A group of adult and pediatric rheumatologists and neurologists reached consensus that, for patients with juvenile and adult PM/DM, the physician and patient/parent global activity score should improve by ≥20% to classify a patient as improved (6). An absolute value for the minimum clinically important difference has not been determined.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The data demonstrate that physician and patient or parent global activity scores are valid overall measures of disease activity, are considered integral in the evaluation of myositis patients, and are part of the core set of activity measures used by several international collaborative groups. The requirement that the patient be assessed by an experienced clinician reduces the likelihood of biases in reporting. The physician global activity score has good content validity and reliability, and both measures have good construct validity and excellent responsiveness in juvenile (ages 2–18 years) and adult PM/DM patients. The 2 measures are clearly distinct.

Caveats and cautions.

To reduce variability, this measure requires training of the person performing the assessment. The VAS may be slightly subjective and somewhat dependent on the experience of the rater. Neither physician nor patient global activity assessments have been formally validated in IBM.

Clinical usability.

The measure should be useful in the assessment of myositis patients, particularly for longitudinal monitoring. Looking at previous measurements in formulating serial ratings is helpful to reduce measurement error. Patients ages >10 years may complete a global activity assessment.

Research usability.

Both physician and patient/parent global activity assessments are well suited to use in research and are becoming widely used in myositis studies and therapeutic trials. They are considered to be a core assessment of disease activity.

MANUAL MUSCLE TESTING (MMT)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

To measure muscle strength as part of the physical examination. No additional equipment is needed. MMT has been widely used in myositis therapeutic trials and clinical studies, previously as a primary end point (1) and more recently as part of a composite end point of core set measures (3). MMT has been reported most often as a summary score of a total number of proximal, distal, and axial muscle groups tested bilaterally or as a proximal score that sums a number of proximal muscle groups from the upper and lower extremities (1, 6). More recently, MMT has been modified to a shorter version called MMT8, in which 8 proximal, distal, and axial muscle groups tested unilaterally closely approximate a total MMT score of 26 muscle groups tested bilaterally (9).

Content.

Both the modified Medical Research Council (MRC) muscle strength scale and the Kendall grading scale are used (1, 6). The modified 0–10-point Kendall grading scale provides firm definitions, along with plus (+) and minus (−) grades that provide an expanded scale. Muscle groups typically chosen include a combination of proximal, distal, and axial muscle groups.

Number of items.

In inclusion body myositis (IBM) studies, 28 muscle groups are usually studied bilaterally, including shoulder abduction, elbow flexion and extension, wrist flexion and extension, hip flexion and extension, knee flexion and extension, ankle dorsiflexion and plantar flexion, and hip abduction. Neck flexion and extension are also tested (10). In polymyositis (PM), dermatomyositis (DM), and juvenile DM, 26 muscle groups are frequently tested (1, 6) and include the above-listed muscle groups except for elbow extensors, but often there is no standardization in the number of muscle groups used. In some trials, only proximal MMT scores are reported, as proximal muscle groups are more affected than distal muscles in PM and DM (9). Recently, a subset of 8 muscle groups, including the neck flexors, deltoids, biceps, wrist extensors, gluteus maximus and medius, quadriceps, and ankle dorsiflexors, tested unilaterally was shown to have similar validity as the total MMT score; other sets of 8 proximal, distal, and axial muscle groups also performed equally well (11).

Response options/scale.

The MRC grades were as follows: 0 = no contraction, 1 = flicker or trace of contraction, 2 = active movement with gravity eliminated, 3 = active movement against gravity, 4 = active movement against gravity and resistance, and 5 = normal power. This scale has been expanded to a 10-point scale in which the ability to resist against varying degrees of pressure in the antigravity position or the ability to move through varying ranges of motion in the gravity-eliminated position earns either a plus (+) or minus (−) in association with a particular grade. The Kendall 0–10-point scale similarly provides an expanded scale by assigning grades to hold the test position against varying degrees of pressure in the gravity-eliminated position or grading the ability to move through full or partial range of motion in the gravity-eliminated position (6).

Recall period for items.

Scoring MMT requires that the activity be performed at the time MMT is administered (i.e., no recall period).

Endorsements.

MMT has been included as a core set activity measure for adult and juvenile PM, DM, and IBM by the International Myositis Assessment and Clinical Studies Group (IMACS) (1) and as a core set activity measure for juvenile DM by the Paediatric Rheumatology International Trials Organisation/American College of Rheumatology/European League Against Rheumatism (2). Muscle strength testing, as assessed by MMT, is also part of the preliminary response criteria for adult and juvenile DM and PM (4, 6).

Examples of use.

Myositis therapeutic trials (1, 6) and natural history studies (12).

Practical Application

How to obtain.

MMT is available in publications that have used it as an assessment tool, free of charge (6). The IMACS web site (http://www.niehs.nih.gov/research/resources/collab/imacs/diseaseactivity.cfm) hosts a number of materials about MMT, including the grading scales, detailed instructions, and training videos.

Method of administration.

MMT is administered by a trained therapist or clinician while observing the patient.

Scoring.

Each muscle group tested is scored by using either the modified MRC or Kendall grading scale, depending on how much the muscle group can do in terms of moving against gravity or against applied pressure. Scores for individual muscle groups range from 0–5 on the MRC scale or from 0–10 on the Kendall scale, which are ordinal grading scales. The scores are summed for a total score or for subscores involving particular muscle groups (proximal, distal, axial scores). Computer programming is not necessary. Missing muscle groups are deleted from the value of the denominator, and the total score is adjusted to the new denominator, so that the percentage of maximum can be obtained.

Score interpretation.

Using the Kendall 0–10 scale, the total MMT score ranges from 0–260 when 12 muscle groups are tested bilaterally along with 2 axial muscle groups. A proximal score of 0–160 represents 8 muscle groups tested bilaterally, a distal score of 0–80 includes 4 muscle groups tested bilaterally on the Kendall scale, and an axial score of 0–20 tests neck flexors and extensors. Normal strength is represented by a higher score at or near the top of the scale. The following interpretations of the scores of individual muscle groups have been used by researchers using MMT to study myositis: a muscle group graded from 0–3 on the Kendall scale indicates severe weakness, grade 4–6 indicates moderate weakness, grade 7–9 indicates mild weakness, and grade 10 indicates no detectable weakness (9). Validated cut points and the clinical meaning of MMT scores have not been established.

Respondent burden.

If all items are attempted, the MMT can take 30–60 minutes to test 26–28 muscle groups. For the MMT8, testing takes <5 minutes. For the weak patient, the testing can be physically demanding and fatiguing, and in our clinical experience, it is important to adequately rest such patients before performing the test.

Administrative burden.

The time it takes to administer the full MMT may be a limitation in a busy clinic, and such testing is typically assigned to a physical therapist to perform in a separate session. Scoring takes <1 minute and can be done by hand. Training in the administration of MMT is important, and can be obtained in local physical therapy or rehabilitation medicine departments. Contributions to measurement error can include inexperience of the examiner, improper positioning of the patient, bias in the application of force or in grading, and inconsistent commands (6). Rheumatologists, for example, typically score patients higher than experienced physical therapists.

Translations/adaptations.

MMT is used internationally. It has been studied and used in all subgroups of myositis, including adult and juvenile PM, DM, and IBM. MMT has been used to assess strength in a variety of neuromuscular conditions.

Psychometric Information

Method of development.

The MRC scale was developed by British physicians during World War II to grade strength after injuries. It was expanded and adapted to neuromuscular research in the 1970s. The shift from the MRC scale to the Kendall grading scale occurred in therapeutic trials of PM/DM in the 1990s because researchers sought to increase the sensitivity and specificity of MMT by expanding the grading scale with clear definitions. MMT had been in widespread use in therapeutic trials but has been validated for myositis only recently. The MMT8 was developed recently as a short form of the MMT that could be more practically applied by physicians testing patients in the clinical setting.

Acceptability.

Although the tool is administered by the therapist or clinician, missing data can be common due to injury or joint contracture. If the data are absent due to an injury, they can be treated as an intent-to-treat point. There are recognized ceiling effects, particularly with known insensitivity of MMT for grades >3 of 5, where variations in the weight of patients' extremities and in the force applied by the examiner can result in discrepancies in detecting mild weakness.

Reliability.
Internal consistency.

In terms of internal reliability, Spearman's correlation was excellent for proximal MMT and MMT8 scores compared with the total MMT score in patients with treatment-refractory adult PM/DM (Spearman's r = 0.91–0.96) and 73 juvenile idiopathic inflammatory myopathy (IIM) patients from a natural history study (Spearman's r = 0.96–0.98) (11). Internal consistency, measured by Cronbach's α, was also very good to excellent for total, proximal, and MMT8 scores, ranging from 0.79–0.93 in adult PM/DM and from 0.90–0.93 in juvenile IIM (11).

Test–retest reliability.

In a study of juvenile IIM patients who were evaluated by 1 pediatric physical therapist in the morning and again in the afternoon, the Spearman's rank correlation coefficient for the total, proximal, distal, and MMT8 scores for each pair ranged from 0.8–0.95 (all P < 0.001) (11). For individual muscle groups, the Spearman's rank correlation ranged from 0.70–1.0 (all P < 0.04) (13).

Interrater reliability.

In a study of juvenile DM patients, interrater reliability was very good, with Kendall's W ranging from 0.71–0.76 for total, proximal, and MMT8 scores (11, 13). The distal score had lower reliability (Kendall's W = 0.51) (13). The reliability of individual muscle groups varies and can be quite poor in distal and upper extremity proximal muscle groups (Kendall's W = 0.04–0.76) (13); therefore, it is important to use summary scores, particularly in research studies.

In a study of adult PM/DM patients, the interrater reliability (assessed by an intraclass correlation coefficient >0.65 or a ratio of the estimates of the standard error attributable to the physicians to the standard error attributable to the patients <0.4), was good for deltoids, biceps, quadriceps, gluteus medius and maximus, and ankle, and was poor for the neck flexors and wrist extensors (14).

Validity.
Content validity.

In developing the MMT8, a group of adult and pediatric rheumatologists and physical therapists agreed upon 3 possible combinations of 8 proximal, distal, and axial muscle groups that closely approximate a total MMT score and could be used in the clinic or in research settings for patients with juvenile and adult DM and PM (11).

Construct validity.

In patients with juvenile PM/DM, total MMT, proximal MMT, and MMT8 scores correlated highly with physical function assessed by the Childhood Myositis Assessment Scale (Spearman's r = 0.70–0.73), and moderately with physician global activity (Spearman's r =0.49–0.54), functional disability measured by the Childhood Health Assessment Questionnaire (Spearman's r = 0.59–0.64), and magnetic resonance imaging (MRI), a score reflecting an average of activity and damage (Spearman's r = 0.45–0.48). MMT scores did not correlate significantly with serum muscle enzymes in patients with juvenile IIM (11).

In patients with adult PM/DM, total MMT, proximal MMT, and MMT8 scores correlated moderately with physical function measured by the Convery Activities of Daily Living Scale (Spearman's r = 0.59–0.70) and MRI (Spearman's r = 0.43–0.50). Correlations with physician global activity (Spearman's r = 0.33–0.37) and creatine kinase (Spearman's r = 0.34–0.38) were mild but significant (11).

Criterion validity.

There is no gold standard upon which to assess criterion validity.

Ability to detect change.

The standardized response mean (SRM) for total MMT was 0.56 in patients with juvenile PM/DM and 0.75 in patients with adult PM/DM in patients reassessed 4 months after baseline evaluation (11). The relative efficiency for proximal MMT (relative to the SRM for the total MMT score) was 0.98 in juvenile DM and 1.08 in adult PM/DM, and for the top MMT8 score was 1.16 in juvenile PM/DM and 1.24 for adult PM/DM (11).

In a study of juvenile DM patients enrolled at diagnosis or requiring escalation of therapy and assessed 6 months later, the SRM for total MMT was 1.2 (95% confidence interval 0.9–1.4) (2). Total MMT was also noted to have good discriminant validity (2).

A group of adult and pediatric rheumatologists and neurologists has reached consensus that MMT should improve by ≥15% to classify an adult PM/DM patient as improved and should improve by ≥18% to classify a juvenile PM/DM patient as improved (6). An absolute value for the minimum clinically important difference has not been determined.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The data demonstrate that MMT is a valid measure of strength, which is considered an integral assessment in the evaluation of myositis patients and part of the core set of activity measures by several international collaborative groups. The requirement that the patient is assessed by an experienced clinician reduces the likelihood of biases in reporting. MMT does not require any special equipment, except for a plinth or table on which the subject can lie flat. MMT has good to excellent reliability when used as a score that sums a number of muscle groups. It has good construct validity and excellent responsiveness in juvenile (ages 4–18 years) and adult PM/DM. It is also widely used to assess patients with IBM.

Caveats and cautions.

To be performed appropriately and to reduce variability, training is required of the person performing the test. Subjects will need to be placed in positions that will be difficult for them to achieve as their weakness progresses. MMT also has decreased sensitivity and specificity in detecting mild weakness. The total MMT takes a long time to administer, but the MMT8, a subset of 8 muscle groups that performs similarly to the total score, is a good substitute in the busy clinical setting. MMT cannot reliably be used to assess children ages <5 years who have limited ability to cooperate. Like other measures of strength and function, MMT does not discriminate between activity and damage and may diminish in sensitivity and specificity as an activity measure for patients who are farther along in their illness course with accumulated damage and progressive muscle atrophy. MMT is frequently used but has not been formally validated in IBM.

Clinical usability.

For some clinicians, the time required for administration limits the usefulness of MMT in the clinical context; however, the MMT8 is more usable in the clinical setting. Many clinicians have found MMT extremely useful for longitudinal monitoring of myositis patients.

Research usability.

MMT is well suited to use in research and has been widely used in myositis studies. Concerns about ceiling effects may mean that it should be used with caution in patients with milder disease and that it will not be sensitive to change in patients with longstanding disease and a lot of muscle atrophy. Resources need to be invested to train a health care provider to perform these studies for a clinical trial.

HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The Stanford HAQ is a brief self-report questionnaire assessing physical function pertaining to activities of daily living in a variety of domains (15). Originally developed for use in rheumatoid arthritis, it has been successfully applied to a variety of rheumatic conditions, including idiopathic inflammatory myopathy (IIM) (16, 17).

A modified version of the HAQ has been used that includes a variety of transitional questions intended to improve the responsiveness of the original tool (18). Although the modified HAQ has been used in myositis (19), there are little specific data regarding its psychometric properties in myositis.

The C-HAQ was adapted directly from the HAQ and was first published in 1994 (20). It was initially used in children with arthritis, but subsequently it has been evaluated in a variety of pediatric illnesses, including juvenile IIM (21, 22). Its brevity and simplicity make it useful for longitudinal monitoring of children with juvenile IIM in the clinic setting.

General information on the HAQ and C-HAQ is covered in several other articles in this issue, specifically the article on measures of functional status and quality of life in rheumatoid arthritis, and only myositis-specific information is discussed here.

Endorsements.

The HAQ has been included as a core set measure by the International Myositis Assessment and Clinical Studies Group (IMACS) (1), and the C-HAQ has been endorsed as a core set activity measure by both IMACS (1) and the Paediatric Rheumatology International Trials Organisation for juvenile IIM (8). These instruments are also part of the preliminary response criteria for adult and juvenile dermatomyositis (DM) and polymyositis (PM) (4, 6).

Examples of use.

The HAQ and C-HAQ have been used as part of myositis natural history studies, and recently have been incorporated as measures of physical function in myositis therapeutic trials (23–25).

Practical Application

How to obtain.

The HAQ and C-HAQ are available from the original publications free of charge (15, 20). They are also available from a variety of internet sites, including the IMACS web site: http://www.niehs.nih.gov/research/resources/collab/imacs/diseaseactivity.cfm.

Psychometric Information

Acceptability.

The HAQ and C-HAQ are brief, and the language is generally at an appropriate level. It is not uncommon for respondents to neglect to complete the sections on the use of aids or assistance to complete tasks. It is recognized that the HAQ and C-HAQ have significant floor effects in all applications (patients with no or mild physical dysfunction cluster near 0).

Reliability.
Internal consistency.

The HAQ has not been formally assessed in adult IIM. In juvenile IIM patients, item-total correlations ranged from 0.35–0.81 by Spearman's r (all P < 0.0001), with only 4 items with a Spearman's r < 0.50 (21). Each domain of the C-HAQ also correlated well with the total score (Spearman's r = 0.59–0.84) (21).

Test–retest reliability.

The HAQ has not been formally assessed in adult IIM. The intraclass correlation coefficient (ICC) was 0.87 for a group of juvenile IIM patients with <10% change by sphygmomanometry of the left hip abductor on consecutive visits (22). For patients with <10% change in the visual analog scale (VAS) of overall illness severity, the ICC was 0.96 (22).

Intra- and interrater reliability.

Not applicable.

Validity.
Content validity.

The HAQ and C-HAQ have not undergone assessment of content validity in adult or juvenile IIM.

Construct validity.

The HAQ has not been formally evaluated. However, in a longitudinal cohort study of patients with PM, DM, or overlap myositis, muscle strength measured by Manual Muscle Testing (MMT) correlated moderately with the HAQ (r = −0.61, P < 0.0001) and mildly but significantly with physician global disease activity (r = 0.28, P = 0.009) (23). The HAQ also correlated moderately with subscales of the Short Form 36, including the physical function, role function, body pain, and role emotional domains (r = 0.42–0.71) (23). In a study validating the Myositis Activities Profile (MAP) for adult PM/DM, a tool to assess limitations of physical activities in IIM patients, the HAQ had a Spearman's r of 0.70 with the MAP (24). In a study of adult PM/DM, the HAQ was shown to correlate significantly with muscle strength testing on the Medical Research Council grading scale and with the Henriksson and Sandstedt measure of functional disability (P < 0.01, correlation not provided), but not with isokinetic muscle strength testing (19). The HAQ correlated mildly but significantly with patient global activity (Pearson's r = 0.34).

In patients with juvenile IIM, the C-HAQ correlated moderately with physician global illness severity VAS (Spearman's r = 0.71, P < 0.002) and with hip abduction and shoulder abduction sphygmomanometry (Spearman's r = −0.57, P < 0.002 and Spearman's r = −0.51, P < 0.01, respectively) (22). Correlations were lower for knee extension and grip strength sphygmomanometry (Spearman's r = −0.40, P = 0.05 and Spearman's r = −0.079, P > 0.20, respectively), as expected (22).

In juvenile IIM, the C-HAQ correlated strongly (Spearman's r = >0.7) with the Childhood Myositis Assessment Scale; moderately (Spearman's r = 0.4–0.7) with physician global disease activity and physician global skin disease activity (by 10-cm VAS), MMT, Steinbrocker functional class, VAS for patient/parent global overall health, illness severity, and muscle symptoms, and the Disease Activity Score; and weakly (Spearman's r = <0.4) with physician global disease damage and skin disease damage (2, 21). In another study of juvenile IIM patients, the C-HAQ showed good correlations with handheld dynometric muscle strength testing (partial correlation adjusted for age = −0.72, P < 0.01) (25). In a study of magnetic resonance imaging in juvenile DM, the C-HAQ correlated well with T2 relaxation time (Pearson's r = 0.49–0.58, P < 0.001) (26).

The C-HAQ correlated moderately with the total and muscle severity scores of the Myositis Damage Index (Spearman's r = 0.45–0.48, P < 0.0001) in juvenile IIM patients with a median disease duration of 6.8 years (27).

Criterion validity.

Although not formally assessed for criterion validity, HAQ scores increase over time in cohort studies of adult DM and PM patients (16, 23). HAQ scores are higher in patients who previously developed avascular necrosis or a compression fracture (16) and in patients with a chronic continuous or polycyclic illness course, osteoporosis, or who have a longer disease duration (23).

Ability to detect change.

Data are not available for the HAQ. However, for the C-HAQ, in juvenile IIM patients enrolled at diagnosis, the responsiveness coefficient was 0.90 (22). For juvenile IIM patients with an improvement of >1 cm on the 10-cm VAS for physician global disease activity over 2 evaluations spanned by 7–9 months, the standardized response mean (SRM) and effect size were 0.87 and 0.67, respectively (21). The C-HAQ showed an SRM of 1.3 in juvenile IIM patients judged by the treating physician to have improved over 6 months (2). The change in C-HAQ scores correlates highly with change in the physical summary score of the Childhood Health Questionnaire (r = −0.73) (28).

A group of adult and pediatric rheumatologists and neurologists has reached consensus that physical function should improve by ≥15% to classify a patient as improved for patients with adult and juvenile PM/DM (6). An absolute value for the minimum clinically important difference has not been determined.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The HAQ and C-HAQ measure physical function, a domain of considerable importance to IIM patients and their health care providers. The tools are brief and take little time, no equipment, and minimal training to administer. They can be used in a variety of contexts (clinic, mail, internet, or phone) and are available in a variety of languages (29). They have been used extensively for a variety of illnesses. Finally, given that they are completed by the patient, parent, or caregiver, they have the advantage of being patient oriented. The C-HAQ has good reliability and excellent construct validity and responsiveness in patients with juvenile (ages 2–18 years) and adult PM/DM.

Caveats and cautions.

From a development point of view, it is not clear that the HAQ or C-HAQ has undergone rigorous attempts to ensure content validity in patients with adult and juvenile IIM. Like other measures of strength and function, the HAQ and C-HAQ do not discriminate between activity and damage and may have poor sensitivity and specificity as a measure of activity for patients with moderate to severe damage, including patients who have muscle atrophy and fixed joint contractures. From an interpretation point of view, the biggest problem with the HAQ and C-HAQ is the floor effect. As patients improve and approach mild physical dysfunction, scores cluster near 0, and there is little room to document further improvement (21). The C-HAQ has been extensively validated in juvenile IIM. Data on validation of the HAQ in adult patients with PM/DM are incomplete, mainly confined to limited construct and criterion validity, and the HAQ has not been studied in inclusion body myositis.

Clinical usability.

There are limited data to support the use of the HAQ in IIM, particularly to assess disease activity, although it still may be useful. The C-HAQ appears to have good reliability, validity, and responsiveness, making it a useful aid in guiding clinical decisions. Its simplicity, brevity, and ease of scoring minimize both administrative and respondent burden, facilitating its routine use in the clinic.

Research usability.

There are limited data on construct validity and criterion validity for the HAQ in adult PM/DM, although it still may be useful. The documented reliability, validity, and responsiveness of the C-HAQ support its use in research. As in the clinical situation, its simplicity, brevity, and ease of scoring minimize the use of research resources. As noted, the floor effect may limit its usefulness in some research (e.g., involving patients with milder or more chronic disease).

CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The CMAS is an observational performance-based instrument that was developed to evaluate muscle strength, physical function, and endurance in children with juvenile idiopathic inflammatory myopathy (IIM) (30, 31). First published in 1999, it has not been revised or updated.

Content.

Items of the CMAS were chosen to explicitly include upper and lower extremity muscle groups, simple and compound movements, and timed items to evaluate endurance. The tool is purposefully weighted toward lower extremity proximal and axial muscle groups more than upper extremity and distal muscle groups to reflect the pattern of weakness in juvenile myositis (9). The tool is not divided into specific domains.

Number of items.

The CMAS consists of 14 items, with no subscales.

Response options/scale.

Specific scoring options are provided for each item, depending on whether the activity can be performed and how much difficulty is required. The endurance items are categorized into ordinal scale scores.

Recall period for items.

Scoring of the CMAS requires that the activity be performed at the time the CMAS is administered (i.e., no recall period).

Endorsements.

The CMAS has been included as a core set activity measure by both the International Myositis Assessment and Clinical Studies Group (IMACS) (1) and Paediatric Rheumatology International Trials Organisation (PRINTO) (2) for juvenile IIM. The CMAS (or alternatively, Manual Muscle Testing [MMT]) is also part of PRINTO's preliminary response criteria for juvenile dermatomyositis (DM) for the evaluation of muscle strength (4).

Examples of use.

The CMAS has been used in validation and natural history studies (2, 12, 32–34) and is currently being used as a core set or ancillary outcome measure in several juvenile and adult polymyositis (PM)/DM therapeutic trials.

Practical Application

How to obtain.

The CMAS is available from the original publication free of charge (31). It is also available from a variety of web resources, including the American College of Rheumatology web site (http://www.rheumatology.org/practice/clinical/pediatric_assessments/cmas.pdf) and the IMACS web site (http://www.niehs.nih.gov/research/resources/collab/imacs/diseaseactivity.cfm), along with detailed instructions and a training videotape.

Method of administration.

The CMAS is administered by a trained therapist or clinician while observing the patient.

Scoring.

Each item of the CMAS is scored depending on whether the activity can be performed and how much difficulty it requires. Scores of individual items range from 0–2 to 0–6, depending on the item. The CMAS can be easily scored by hand.

Score interpretation.

The total CMAS score ranges from 0–52, with 52 representing normal or near-normal strength, function, or endurance. Age- and sex-related normal values for children ages 4–9 years have been published for 9 of the items, which document that younger children might not be able to reach a score of 52 (4). Validated cut points have not been established. However, as part of a consensus process, it was agreed that values <15 represented severe disease (32). In another publication, using a process that compared CMAS values to Childhood Health Assessment Questionnaire (C-HAQ) scores, values corresponding to no, mild, mild to moderate, and moderate impairment were 48, 45, 39, and 30, respectively (30).

Respondent burden.

Assuming that all items can be attempted, the CMAS takes 15–20 minutes to complete. Some of the activities may be challenging for the weak child, and the overall assessment can be physically demanding for some.

Administrative burden.

The ∼15 minutes it takes to administer the CMAS may be a limitation in a busy clinic. Scoring takes <1 minute and can be done by hand. Training in the administration of the CMAS is preferred. Proper equipment is needed to complete the entire test, including access to a step stool and chairs of appropriate height. Access to a watch with a second hand is needed, and a floor mat is helpful for the comfort of patients completing items performed on the floor.

Translations/adaptations.

None available at present. The CMAS has been validated and studied in juvenile IIM patients. There have been no studies to date in adult myositis patients, although unpublished experience suggests the CMAS can also be used in adult myositis patients (Rider LG: unpublished observations).

Psychometric Information

Method of development.

The 14 items of the CMAS were taken from and/or adapted from 2 unpublished clinical tools used by authors of the original CMAS publication (31). In this process, items from the 2 tools were reviewed by a group of pediatric rheumatologists, as well as a physical therapist and a physiatrist. Through consensus and observation of children with juvenile IIM attempting candidate items, the resulting 14-item tool was arrived at. Development of the scoring of each item was not described (31).

Acceptability.

Although the tool is administered by the therapist or clinician, missing data can be common in children ages <5 years because of their limited ability to cooperate. Inability to complete a task is scored as 0. There are recognized ceiling effects (little change as children approach normal strength).

Reliability.
Internal consistency.

Not available.

Test–retest reliability.

For juvenile IIM patients evaluated by trained assessors who evaluated the same patients in the morning and again in the afternoon, the Pearson's correlation coefficient for the total scores for each assessor pair ranged from 0.97–0.99 (all P < 0.001) and was 0.98 for the overall correlation of all assessors (31).

Interrater reliability.

In juvenile IIM patients evaluated by 2 assessors, the intraclass correlation coefficient of the total score was 0.89 (very good) (30). In patients with juvenile IIM evaluated by 12 assessors, Kendall's W for each item ranged from 0.77–1.0 (all P < 0.001) and was 0.95 for the total score (31).

Validity.
Content validity.

This has not been formally assessed in juvenile IIM.

Construct validity.

In children with juvenile IIM, the CMAS correlated highly with the C-HAQ and total MMT score (Spearman's r = −0.73 and 0.73, respectively, P < 0.0001) and moderately with physician global disease activity, physician skin activity, and parent disease severity, as well as serum creatine kinase and prednisone dose (Spearman's or Pearson's r = −0.61 to −0.44, P < 0.0001) (30, 31). Correlations with magnetic resonance imaging of muscle edema and damage were moderate (Spearman's r = −0.57 to −0.48), and correlations with serum levels of enzymes were low but often significant (Spearman's r = −0.36 to −0.11). Correlations with the 10-cm visual analog scale (VAS) for physician global disease damage and physician skin disease damage were appropriately low (Spearman's r = −0.15 to −0.02, P > 0.01) (30).

Finally, in an international study of juvenile IIM, the CMAS correlated moderately with the Disease Activity Score (Spearman's r = −0.54), 10-cm VAS of parent overall disease severity (Spearman's r = −0.56), and physical summary score of the Childhood Health Questionnaire (Spearman's r = 0.61), and correlated highly with the C-HAQ (Spearman's r = −0.71) (2).

Criterion validity.

Not available.

Ability to detect change.

In children with juvenile IIM reassessed 7–9 months later, the overall standardized response mean (SRM) was 0.42 (95% confidence interval [95% CI] 0.21–0.63) (30). When those children with a 0.8-cm improvement in physician global disease activity were considered, the SRM was 0.89 (95% CI 0.53–1.09) (30). Finally, in children with juvenile IIM enrolled at diagnosis or requiring an escalation of therapy and reassessed 6 months later, the SRM was 1.4 (95% CI 1.2–1.5) (2).

A group of adult and pediatric rheumatologists and neurologists has reached consensus that measures of physical function should improve by ≥15% to classify a patient as improved for patients with juvenile and adult PM/DM (33). An absolute value for the minimum clinically important difference has not been determined.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The data demonstrate that the CMAS is a valid measure of strength, physical function, and endurance, which are of great importance to patients, families, and care providers. The requirement that the child being assessed is observed reduces the likelihood of biases in reporting. This instrument has excellent reliability, construct validity, and responsiveness in juvenile myositis for patients ages 4–18 years.

Caveats and cautions.

Some clinicians believe that the CMAS takes too much time to administer. There are some concerns about ceiling effects. Appropriate training is necessary to reduce variability in assessments. The CMAS is difficult to assess in the youngest children with limited ability to cooperate. Like other measures of strength and function, the CMAS does not discriminate between activity and damage, and it may have poor sensitivity and specificity as a measure of activity for patients with moderate to severe damage, including patients who have muscle atrophy and fixed joint contractures. The CMAS has been validated and studied in juvenile IIM but not in other myositis subgroups.

Clinical usability.

For some clinicians, the time required for administration limits the usefulness of the CMAS in the clinical context. However, others have found the CMAS extremely useful, particularly for longitudinal monitoring of patients.

Research usability.

The CMAS is well suited to use in research. Concerns about ceiling effects may mean that it should be used with caution in patients with milder disease.

MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The MDAAT is a tool that assesses disease activity of extramuscular organ systems and muscle to assess patients with adult and juvenile dermatomyositis (DM), polymyositis (PM), and inclusion body myositis (IBM). The MDAAT is a combined tool that includes the Myositis Disease Activity Assessment visual analog scale (VAS) (MYOACT) and the Myositis Intention to Treat Activities Index (MITAX). The MYOACT is a series of physician's assessments of disease activity in various organ systems using a VAS to assess the severity of activity that has been modified from the Vasculitis Activity Index (35), and the MDAAT is based on an intent-to-treat approach and modified from the British Isles Lupus Assessment Group (BILAG) approach to assess disease activity in lupus (36). The MITAX was published in 2004 (14) and updated in 2008, wherein items from the MITAX that were rarely scored were removed, glossary definitions clarified, and the criteria for scoring interstitial lung disease altered (37). The key issue in relation to the MDAAT is to ensure that the items recorded are, in the view of the physician, actually due to the active myositis and not due to disease damage, another unrelated disease process, or a side effect of medication.

Content.

The MITAX assesses specific manifestations in 7 organs/systems, including constitutional, cutaneous, skeletal, gastrointestinal, pulmonary, cardiac, and muscle. The MYOACT consists of a 10-cm VAS for each organ system to score the overall severity of activity in each and a global extramuscular VAS.

Number of items.

For the MYOACT, each organ system has a single VAS; a global extramuscular activity VAS is also scored. The VAS are anchored at the end points and midpoint. For the MITAX, 3–9 items consisting of symptoms/physical findings or laboratory abnormalities are assessed in each of the 7 organs/systems.

Response options/scale.

For the MYOACT, the scores range from 0–10 cm. For the MITAX, each question is answered as 0 = not present, 1= improving, 2 = the same, 3 = worse, or 4 = new.

Recall period for items.

Within 4 weeks.

Endorsements.

Extramuscular activity has been considered by the International Myositis Assessment and Clinical Studies Group (IMACS) to be a core set activity domain, and the MDAAT is considered a validated tool to assess this domain in patients with adult and juvenile PM/DM (6). The MDAAT (either MYOACT or MITAX) is accepted by the Paediatric Rheumatology International Trials Organisation as a core set measure to assess the core set domain of global disease activity tool (2). The extramuscular activity from the MYOACT or MITAX is part of the preliminary criteria for response for adult and juvenile PM/DM (4, 6).

Examples of use.

The MDAAT has been used in natural history studies with the purpose of validating the tool (14, 37), in studies examining disease activity (38), and as an outcome measure in therapeutic trials for adult and juvenile PM/DM.

Practical Application

How to obtain.

The paper version is available at no cost. The tool is posted on the IMACS web site (http://www.niehs.nih.gov/research/resources/collab/imacs/diseaseactivity.cfm), along with slide sets for the cutaneous section and sample cases for training in scoring. The British Lupus integrated program (BLIPs) package, which includes activity measures for both lupus and myositis, can be obtained from Gordon Hamilton (e-mail: gordon.hamilton@limathon.com or Limathon@aol.com) (39). The cost of the computer version depends on the type of usage (commercial or academic). For further information about BLIPs, please contact Professor David Isenberg (e-mail: d.isenberg@ucl.ac.uk).

Method of administration.

Clinician-completed, in-person administration based on history and examination.

Scoring.

For the MYOACT, scores for each organ system and the extramuscular global activity are derived by measuring the distance the vertical line is from the left-hand side of the horizontal VAS. The length of the VAS should also be measured, so that the score can be adjusted to a denominator of 10 cm. For the MITAX, each clinical feature is recorded using a scale of 0–4, where 0 = not present, 1 = improving, 2 = the same, 3 = worse, and 4 = new. This score is then converted by a scoring schema to a final score ranging from A–E for each system, where A indicates very active disease requiring treatment with high-dose daily corticosteroids or a significant immunosuppressive therapy, B indicates a need for modest doses of corticosteroids and/or ongoing immunosuppression, C indicates a need for low-dose steroid or symptomatic drugs only, D indicates that the system is no longer active, and E indicates that the system was never active. Each organ system receives only a single A–E score (which can be numerically converted to A = 9, B = 3, C = 1, and D/E = 0 to obtain a global score) based on the score of the most severe item in that organ system. There has been work that has reassessed the scoring in lupus that may impact the scoring of the MITAX in the future (40). The tool can be scored by hand, but the BLIPs computer package can be obtained to convert the clinical assessments and provide the MITAX score.

Score interpretation.

For the MYOACT, each organ system is scored from 0–10, and the 6 extramuscular organ systems can be summed to obtain an extramuscular score of 0–60, or a total score that includes the muscle system that ranges from 0–70. For the MITAX, the organ system scores are summed to obtain a total MITAX score with a range of 0–63, or 0–54 when the muscle system is excluded. The MITAX A–E organ system scores are intended to correspond with therapeutic choices for the patient, based on their level of disease activity. Normative data are not available.

Respondent burden.

Not applicable.

Administrative burden.

A complete history and physical examination are needed. To assess a patient in remission or close to remission takes <5 minutes. For a patient with a complex condition and who is not well known to the physician, it can take up to 15–20 minutes. For scoring, the BLIPs program can be run in the clinic or at a later time in ∼5–7 minutes. Hand scoring may take a few extra minutes. Training using the resources on the IMACS web site is helpful.

Translations/adaptations.

Only an English language version is available for both the paper and computer versions. The measure was developed and validated specifically for patients with inflammatory muscle disease, particularly for adult and juvenile PM/DM, although it should also be applicable to patients with IBM.

Psychometric Information

Method of development.

The MITAX and MYOACT tools were developed from the BILAG for lupus and the Vasculitis Activity Index. Study evaluation forms from the Juvenile DM Disease Activity Study Group were used to develop the content of the subscales and some of the items, including adoption of elements of the Cutaneous Assessment Tool to the cutaneous organ system. The draft versions of the MITAX and MYOACT, including the glossary, were commented on and further refined by >75 members of IMACS using a Delphi approach. Two interrater reliability exercises using adult and juvenile PM/DM patients were performed that resulted in further refinement to the tool based on ease of use and understanding of the experienced adult and pediatric specialists who participated (14). During the course of a large multicenter study of adult PM/DM patients, the tool was further refined to improve the criterion validity (37).

Reliability.
Internal consistency.

In a natural history study of adult PM/DM patients to validate the MDAAT, correlation between the MYOACT and MITAX instruments for the individual organ systems was good, with correlation coefficients ranging from 0.80–0.94 (37).

Test–retest reliability.

Not available.

Interrater reliability.

In the initial study of adult PM/DM patients assessed by 7 raters, the reliability was considered good (with an intraclass correlation coefficient [ICC] of >0.65 or the ratio of the estimates of the standard error attributable to the physicians to the standard error attributable to the patients <0.40) for each of the organ systems of the MYOACT and MITAX, except for the MITAX constitutional system and the total MITAX score (14). Pediatric rheumatologists assessed juvenile DM patients, and the interrater reliability was also generally good, except for the skeletal system of the MITAX (6). The reliability studies were performed with prior training in the use of the tool and in the assessment and scoring of myositis activity.

Reliability was demonstrated in a 2-phase study of adult myositis patients evaluated in 7 centers and subsequently in patients reevaluated in 2 centers by 2 physicians at each center. The ICC was ≥0.6 in 5 of the 7 organ systems of the MYOACT and MITAX, as well as the total MITAX score, indicating generally good rater agreement. The mucocutaneous system of the MYOACT had the poorest interrater reliability (ICC 0.205) (37).

Validity.
Content validity.

Content validation is described above in Method of development.

Construct validity.

From a large study of adult patients with PM/DM, the total MITAX score correlated moderately with physician global activity (Spearman's r = 0.69). The muscle MYOACT score also correlated moderately with the serum creatine kinase level (Spearman's r = 0.61) (37). In a separate study, the arthritis MYOACT and MITAX scores correlated moderately with Jo-1 autoantibody titers as a surrogate measure of disease activity (Spearman's r = 0.39–0.42), and mildly but significantly with the muscle MYOACT and MITAX scores, as well as with the total MITAX score (Spearman's r = 0.30–0.37) (38). In a study of juvenile idiopathic inflammatory myopathy patients and studies of treatment-refractory adult PM/DM patients, the MYOACT extramuscular global activity score correlated moderately with other core set measures of disease activity, including physician global activity, Manual Muscle Testing, Childhood Myositis Assessment Scale, and Childhood Health Assessment Questionnaire (Spearman's r = 0.29–0.54) (6).

Criterion validity.

The criterion validity of the tool was measured by comparing the MITAX A score to the gold standard, defined as starting or increasing disease-modifying therapy in patients with adult PM/DM. The overall sensitivity and specificity in obtaining an A score on the MITAX index was 86% overall, with a specificity of 92%. The positive predictive value for a MITAX grade A score was 67% overall (37).

Ability to detect change.

In a study of juvenile DM patients who were close to diagnosis or in need of disease-modifying therapy, the MYOACT extramuscular global activity score had a standardized response mean (SRM) of 1.3 (95% confidence interval [95% CI 1.1–1.5). The SRM for the total MITAX score was 1.2 (95% CI 1.0–1.3). In this same study, the MYOACT extramuscular global activity score and the total MITAX score showed good discriminant validity between patients who were rated as improved versus those who had not improved at 6-month reevaluation (2). In treatment-refractory adult PM/DM patients enrolled in therapeutic trials, the SRM was −0.4 but improved to −1.2 in patients who met the criteria for therapeutic response (6).

A group of adult and pediatric rheumatologists and neurologists has reached consensus that extramuscular activity should improve by ≥20% to classify a patient as improved in patients with juvenile and adult PM/DM (6). An absolute value for the minimum clinically important difference has not been determined.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The MDAAT, consisting of the MYOACT and the MITAX, provides the only in-depth disease activity score that captures a variety of organ systems that comprise extramuscular involvement. The muscle system as part of the full tool also comprises an integrated disease activity tool. Both the MITAX and MYOACT have excellent content validity, with a large amount of input in their development from myositis researchers and based on reliability study data. They also have good interrater reliability, moderate construct validity, and excellent responsiveness in adult and juvenile PM/DM patients (ages 2–18 years).

Caveats and cautions.

The tool has been criticized by clinicians less experienced with myositis as being difficult to understand and score. However, in essence, the tool facilitates clinicians' asking their patients a comprehensive series of questions related to their disease, recording the symptoms as absent, better, same, or worse compared to the previous month. Training and experience with myositis patients clearly improve the reliability. Examination of previous MYOACT scores should reduce measurement error on serial evaluation. The VAS may be subjective and somewhat dependent on the experience of the rater. Although the MDAAT is recommended for use in patients with IBM, it has not been formally validated in this subgroup.

Clinical usability.

The criterion validity of the MITAX A score supports use in the clinical setting. The time to administer the tool would not be much greater than a routine clinical assessment, but the burden is greater in complex patients or in patients with whom the physician lacks familiarity.

Research usability.

The psychometric properties support its use in research studies and therapeutic trials. Training in the administration and scoring of the tool is important to improve reliability.

DISEASE ACTIVITY SCORE (DAS)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The DAS was developed to assess overall disease activity in juvenile dermatomyositis (DM) (41, 42). The tool assesses muscle and cutaneous manifestations, including vasculopathic features, based on bedside clinical assessment.

Content.

The DAS consists of 19 items, resulting in a score of 0–20: 10 items are scored dichotomously (the indicator is present or not) and 3 polychotomously (rating severity level or extent to which the indicator is present). In addition to the total score, it is also possible to report the DAS skin score (range 0–9) and the DAS muscle score (range 0–11) separately. According to the authors, the approximately equal contribution of items relating to muscle and skin reflects their equal importance in the disease pathophysiology.

Number of items, response options, and scoring.

The presence or absence of weakness is assessed via 8 variables: neck flexor muscles, abdominal muscles, upper extremity proximal muscles, lower extremity proximal muscles, Gower's sign, abnormal gait, difficulty swallowing, and nasal speech. Functional status consists of a 4-point scale, ranging from normal function to severe limitations in daily life functions. The presence or absence of vasculitis is assessed by determining the presence of any 1 of the following: eyelid erythema, eyelid vessel dilation, eyelid thrombosis, nailfold erythema, nailbed telangiectasia, dilation of blood vessels on the palate, and “other” vasculitis. The presence of rashes is rated using polychotomous scales: the distribution of the involved skin is rated on a 4-point scale, ranging from none to generalized, while the severity of skin involvement is rated on a 5-point scale, ranging from absent to severe. Gottron's papules are rated on a 4-point scale, ranging from absent to severe, including evidence of atrophic lesions (which usually disappear entirely but can sometimes flare).

Recall period for items.

The DAS refers to the status of the patient, as assessed by a trained health professional, on the day of the clinic visit. There is no recall period.

Endorsements.

The DAS has been endorsed by the Paediatric Rheumatology International Trials Organisation (PRINTO) (8) as one of the 6 core set disease activity measures to be used to evaluate response to therapy in juvenile DM (2, 4, 43). Although the DAS has not been endorsed by the International Myositis Assessment and Clinical Studies Group (IMACS) as a core set measure, the group has recommended that it be included in future studies assessing outcomes and outcome measures for adult and juvenile myositis (http://www.niehs.nih.gov/research/resources/collab/imacs/main.cfm). The DAS, as a global disease activity tool, is also part of the PRINTO preliminary response criteria for juvenile DM (4).

Examples of use.

The DAS has been used in validation and in natural history studies of juvenile DM, and has been incorporated as an end point in therapeutic studies (2, 41–44).

Practical Application

How to obtain.

The DAS is published and can be used free of charge for not-for-profit studies (42). The tool is also publicly available on the IMACS web site (http://www.niehs.nih.gov/research/resources/collab/imacs/main.cfm), along with instructions for administering the tool and training materials for the skin assessment.

Method of administration.

Clinician-completed in-person administration.

Administrative burden.

No information is available on the time to complete the questionnaire, but based on clinical use it takes 5–15 minutes to complete. The DAS can be completed by a physician or an allied health professional with adequate training.

Scoring.

The total score ranges from 0–20, with the skin subscore ranging from 0–9 and the muscle subscore ranging from 0–11.

Score interpretation.

A higher score indicates more active disease. Although normative data are not available, a normal score would be 0.

Translations/adaptations.

None available at present. The DAS has been studied in patients with juvenile DM but not in other subgroups of patients with myositis.

Psychometric Information

Method of development.

The DAS was developed at the Juvenile Myositis Clinic at Northwestern University Medical School's Children's Memorial Hospital (Chicago, Illinois) with the goal to rapidly assess how each child's clinical status has evolved over time (41).

Acceptability.

The questionnaire is simple and easy to score. No specific information on the rate of missing data is available. However, in the PRINTO study, it was possible to calculate the DAS score in 99.3% of 275 patients (2).

Reliability.
Internal consistency.

The DAS produces a reliable estimate of disease activity (person separation = 2.80 compared with the criterion of 2.00) that distinguishes at least 3 distinct strata of disease activity in the sample: high, average, and low. The separate skin and weakness measures were less reliable, suggesting that both components are needed to adequately measure disease activity (41). Although the ratings across items were internally consistent, differences in practitioner sensitivity and specificity to individual disease activity indicators were found (42).

Interrater reliability.

Using cutoffs of 0.40 and 0.20 to identify good and marginal agreement, respectively, 6 of the items for which coefficients could be estimated had good agreement, 6 had marginal agreement, and 4 had poor agreement as estimated by kappa coefficients (41). For most cases (∼80%), the estimated disease activity measures were essentially the same across different physician raters. This result was confirmed by a Pearson's correlation coefficient of 0.79 between the 2 estimates of disease activity for each patient (41).

Test–retest reliability.

Not available for juvenile DM.

Validity.
Content validity.

The fit of the DAS items to the disease activity construct is within acceptable levels (fit statistic values <1.30). Additionally, the relationship between measures of muscle strength and weakness is strong and negative (r = −0.77), with more strength (as rated by therapists using Manual Muscle Testing) being highly associated with less weakness (as rated by physicians using the DAS). The relationship between measures of disease activity and disability is weak (r = 0.20) (41).

Construct validity.

The Spearman's correlation coefficients for the baseline to 6-month change in the DAS with the remaining 5 PRINTO/American College of Rheumatology/European League Against Rheumatism juvenile DM core set measures (physician's global activity assessment, Childhood Myositis Assessment Scale, Childhood Health Assessment Questionnaire, parent's global assessment of the patient's overall well-being, and Childhood Health Questionnaire physical summary score) were in the moderate range (Spearman's r = 0.4–0.6) (2). The DAS correlated moderately with other core set measures of disease activity (Spearman's r = 0.42–0.6) (2). The DAS skin score, but not muscle score, correlated weakly with periungual capillary loss (end row loops Spearman's r = −0.36) as well as with serum levels of muscle enzymes (42).

Criterion validity.

There is no gold standard by which to establish criterion validity.

Ability to detect change.

In the PRINTO study of juvenile DM, in a population requiring the initiation of new therapies, the standardized response mean of the DAS was 1.7 (95% confidence interval [95% CI] 1.5–1.9) (2). The DAS demonstrated significant ability to discriminate among patients who improved or did not improve at 6-month followup based on the physician's or parent's assessment of the child's response to therapy (2).

In the final logistic regression model of the PRINTO juvenile DM core set measures' ability to predict improvement, the physician's global assessment of the patient's overall disease activity and the DAS appeared to be the strongest predictors of response to therapy, with odds ratios of 3.4 (95% CI 1.5–7.4) and 3 (95% CI 1.4–6.5), respectively (2).

In a study of juvenile DM patients seen in followup, periungual nailfold capillary dropout was moderately associated with the skin DAS score (β = −0.159, P < 0.0001) and more modestly associated with the muscle DAS score (β = −0.044, P < 0.0001) (44).

The minimum clinically important difference has not been established for juvenile DM.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The DAS evaluates muscle weakness and skin disease activity, in particular both erythematous and vasculopathic rashes, in patients with juvenile DM. The DAS has been established as one of the 6 juvenile DM core set of measures of disease activity established by PRINTO, as it is a disease-specific global tool (8). The DAS was selected for use as a core set measure because of its superior responsiveness to clinically important change (and minor skewness) compared with the Myositis Disease Activity Assessment and Myositis Intention to Treat Activities Index; moreover, the DAS was the only index that used the entire range of possible scores (median score at baseline 12, range 0–20). The DAS has good internal consistency and construct validity and excellent responsiveness, but moderate to poor interrater reliability in patients with juvenile DM (ages 2–18 years).

Caveats and cautions.

Several areas of the DAS are noteworthy for potential problems: the muscle weakness and function component, like all other measures of weakness and function in myositis, consists of a combination of both activity and damage indicators that may have poor sensitivity and specificity as an activity measure for patients with moderate to severe damage. Atrophic skin rashes are similarly scored, yet are considered a measure of damage rather than activity. The DAS does not capture involvement of all organ systems and has been studied in patients with juvenile DM, but not in other myositis subgroups.

Clinical usability.

While the DAS is relatively simple to use with training and has overall good psychometric properties in patients with juvenile DM, the clinical meaning of scores has not yet been established, making this tool difficult to apply to the care of individual patients.

Research usability.

The DAS has been well validated for juvenile DM, and given its psychometric properties and ease of use with training, it is appropriate for use in the research setting. The clinical meaning of DAS scores and clinically meaningful change in scores have yet to be established in the context of therapeutic trials (43). Studies of the DAS are needed in other myositis subgroups.

SHORT FORM 36 (SF-36)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The SF-36 is a widely used tool that assesses the global medical quality of life, functional health, and well-being of general and specific populations. The SF-36 is covered in detail in the article in this issue on adult measures of general health and health-related quality of life for further information. This section will cover only information on the SF-36 that is specific to myositis.

Endorsements.

The SF-36 has been proposed by the International Myositis Assessment and Clinical Studies Group (IMACS) (http://www.niehs.nih.gov/research/resources/collab/imacs/abouttools.cfm) as an important patient-reported outcome measure to be used to evaluate response to therapy in all forms of myositis (1).

Examples of use.

The SF-36 has been used in several small natural history studies of polymyositis (PM), dermatomyositis (DM), amyopathic DM, overlap myositis, and inclusion body myositis (IBM) (23, 45–47), and in 2 exercise studies of PM and DM (48, 49).

Practical Application

Translations/adaptations.

The SF-36 is now available in many different languages (for details, e-mail info@iqola.org). It has been studied in a limited way in relatively small numbers of patients with adult PM, DM, amyopathic DM, overlap myositis, and IBM, but has been extensively studied in many other chronic diseases. The SF-36 is not recommended for use with children.

Psychometric Information

Reliability.

Data are not available in myositis.

Validity.
Content validity.

None available in myositis.

Construct validity.

In adult PM, DM, or overlap myositis, the physical functioning domain of the SF-36 correlated highly with the Health Assessment Questionnaire (HAQ) disability index (r = −0.71), whereas the HAQ correlated moderately with other domains of the SF-36, including role function, bodily pain, and emotional domain (r = −0.52 to −0.42). Manual Muscle Testing (MMT) scores, but not physician global activity, correlated moderately with SF-36 physical functioning, role functioning, and bodily pain (r = −0.57 to −0.27) (23). For patients with IBM, the physical functioning domain of the SF-36 correlated strongly with MMT, timed stand, timed walk, and the Amyotrophic Lateral Sclerosis Functional Rating Scale (46). In patients with adult DM or amyopathic DM, SF-36 subscales, including physical functioning, role functioning, physical, bodily pain, and general health, correlated mildly to moderately with physician global activity (Pearson's r = 0.30–0.42), and the social functioning, role functioning, and emotional and mental health domains of the SF-36 correlated more strongly with the Skindex emotion subscale (Pearson's r = 0.52–0.63). There was also a moderate negative correlation between grip force and the SF-36 health-related quality of life dimensions vitality and mental health in women with DM and PM (Spearman's r = −0.53 to 0.48) (47).

Criterion validity.

In several studies from different countries, the SF-36 overall scores, and most or all of the 8 domain subscores, were significantly lower in patients with adult DM, PM, and IBM than in the general population. The physical functioning and role functioning domains were particularly impaired in myositis patients (23, 45–47). Patients with chronic progressive illness had significantly greater bodily pain than those with relapsing–remitting illness (45).

Ability to detect change.

Responsiveness statistics are not available in myositis.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The SF-36 is a widely used and easily administered tool that is available in many languages. It has shown evidence of content, concurrent, criterion, construct, and predictive validity in many different chronic diseases, and extensive normative data are available. It is also recommended by IMACS as an important measure to assess patient-reported outcomes in all forms of adult idiopathic inflammatory myopathy. It has good construct and content validity in adult DM, PM, and IBM patients, and is not applicable to children with idiopathic inflammatory myopathy.

Caveats and cautions.

The major drawbacks of the SF-36 are its limited use to date in myositis and the inconvenience and cost associated with obtaining a license to use it. Additional studies in all myositis subgroups are needed to more fully validate the tool and understand its role in assessing quality of life in myositis, particularly the reliability and responsiveness of the SF-36. The availability of recent variations of the SF-36, including the SF-36 version 2, SF-12, and SF-8, complicates the decision of which version to use in a given study.

Clinical and research usability.

The SF-36 is easily administered to patients and is easily scored, making it appropriate for both clinical and research use. However, its cost may limit its use. The lack of data on responsiveness in myositis patients is a limitation for its use in myositis therapeutic trials.

CHILD HEALTH QUESTIONNAIRE (CHQ)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The CHQ, originally developed in the US in 1996, is a generic instrument administered to both parent and child designed to capture the physical, emotional, and social components of health status in children ages 5–18 years (50). As a generic questionnaire it can be used across different childhood conditions, and it has also been validated for use in juvenile dermatomyositis (DM) (28). The general content of the tool was discussed in other sections of this issue (see the article on measures of health status and quality of life in juvenile rheumatoid arthritis); therefore, only information specific to myositis will be discussed here.

Content.

The CHQ consists of 14 health concepts: global health, physical functioning, role/social limitations–emotional/behavioral, role/social limitations–physical, bodily pain/discomfort, behavior, general behavior, mental health, self-esteem, general health perception, parent impact–emotional, parent impact–time, family activities, and family cohesion. In addition, there are 2 summary measures, the physical summary score (PhS) and the psychosocial summary score (PsS).

Endorsements.

The CHQ PhS has been selected by the Paediatric Rheumatology International Trials Organisation (PRINTO; online at www.printo.it) (51) as a core set of measures to be used to evaluate response to therapy in juvenile DM (2, 4, 8). The CHQ, as an assessment of health-related quality of life (HRQOL), is also part of PRINTO's preliminary response criteria for juvenile DM (4). The International Myositis Assessment and Clinical Studies Group has proposed that HRQOL is an important patient-reported outcome measure to be used to evaluate response to therapy in all forms of myositis (1).

Examples of use.

The CHQ has been used in validation and in natural history studies of juvenile DM (2, 28).

Practical Application

Translations/adaptations.

The CHQ is now available in 70 different languages (for details, see www.healthactchq.com), with 32 versions cross-culturally adapted and validated by PRINTO (29, 52). The CHQ has been studied in patients with juvenile idiopathic arthritis, juvenile DM, and other chronic childhood diseases. Because it is a pediatric tool, the CHQ is not appropriate for use in adult myositis subgroups.

Psychometric Information.

Method of development.

Data regarding psychometric issues are extensively reported in the CHQ manual and can also be found in the supplement published by PRINTO (29, 52) for each of the 32 validated translations. The psychometric properties of the CHQ have been established mainly for juvenile idiopathic arthritis and are discussed in this issue in the article on measures of health status and quality of life in juvenile rheumatoid arthritis. However, data were further confirmed in a study that investigated the change over time of HRQOL in patients with active juvenile DM, as measured by the CHQ.

To appropriately evaluate the underlying framework and psychometric properties of the CHQ, PRINTO used item-scaling multitrait analysis software. Since the main validation analysis was conducted when the original English versions of the CHQ (28) were developed in the US, the PRINTO revalidation of the questionnaire was set up as “confirmatory,” meaning that the PRINTO results were considered successful if they were equal to or superior to the results published for the original American English version of the CHQ.

Acceptability and reliability.

This has not been assessed in juvenile DM.

Validity.
Content validity.

In a study by PRINTO, the mean ± SD CHQ PhS and PsS were significantly lower in juvenile DM patients than in healthy children (33.7 ± 11.7 versus 54.6 ± 4.1 and 45.1 ± 9.0 versus 52 ± 7.2, respectively), with physical well-being domains being the most impaired. In addition, both the PhS and PsS decreased with increasing level of disease activity and muscle strength, and inversely correlated with the parent's evaluation of the child's overall well-being. The study also showed that a Childhood Health Assessment Questionnaire (C-HAQ) score >1.6 (odds ratio [OR] 5.06), a child's overall well-being score >6.2 (OR 5.24), and to a lesser extent muscle strength and alanine aminotransferase level were the strongest determinants of poorer physical well-being at baseline, whereas baseline disability and longer disease duration were the major determinants for poor physical well-being at followup (28).

Construct validity.

In terms of content validity, the CHQ correlates strongly with the C-HAQ (Spearman's r = −0.73) and moderately with the Childhood Myositis Assessment Scale (Spearman's r = 0.61) and other core set measures of disease activity (Spearman's r = −0.42 and −0.58 with physician and parent global activity and Disease Activity Score, respectively) in juvenile DM (2).

Criterion validity.

There is no gold standard by which to establish criterion validity.

Ability to detect change.

Responsiveness was tested specifically in juvenile DM, in which patients with active disease who needed to increase therapy were assessed at baseline and after 6 months. The standardized response mean of the PhS of the CHQ in this PRINTO study was 1.0 (95% confidence interval [95% CI] 0.9–1.2), whereas that of the CHQ PsS was 0.5 (95% CI 0.3–0.6) (2). The PhS of the CHQ did not have significant discriminant validity to separate juvenile DM patients whose disease was considered to be improved after initiation of new therapy from those whose disease did not improve (2).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

One of the 6 components of the juvenile DM core set established by the American College of Rheumatology/European League Against Rheumatism/PRINTO is the evaluation of the domain HRQOL, and the PhS of the CHQ has been suggested as a possible tool for evaluating that domain (other tools might also be used).

The CHQ has good content and construct validity and responsiveness in large studies of juvenile DM for children ages 2–18 years.

Caveats and cautions.

The major limitations of the CHQ are its length and the fact that the parent version is mainly used for clinical research because the child version is too long to be used in research or clinical settings. Several other HRQOL scales are available for use in children with pediatric rheumatic diseases (53, 54); however, most of them have remained essentially research tools and are not routinely administered in most pediatric rheumatology centers. There is a degree of redundancy between the PhS of the CHQ and the C-HAQ, as both are measures of physical function, although the CHQ has a broader construct in assessing HRQOL more generally (2).

Clinical usability.

The psychometric evaluation would support interpretation of scores to make decisions for individual patients. Two reasons that this instrument is not commonly incorporated in standard clinical care are its length and complexity.

Research usability.

The psychometric evaluation supports use of the CHQ for research studies of juvenile DM. The administrative and respondent burden may limit its use. Studies for other myositis subgroups are needed.

PHYSICIAN GLOBAL DAMAGE

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

An overall rating of the disease damage related to myositis, defined as persistent changes in anatomy, pathology, physiology, or function, such as fibrosis, scarring, or atrophy, resulting from any cause (including prior treatment) since the onset of the myositis. Features of damage, or the pathology that led to the feature, must be present for at least 6 months despite immunosuppressive or other therapy, including exercise and rehabilitation (1).

Content.

The global assessment of disease damage is to be judged by the physician based on all of the information available at the time of the evaluation, including the subject's appearance, medical history, physical examination, laboratory testing, and the prescribed medical therapy. The global disease damage assessment is completed on a 10-cm visual analog scale (VAS) that is often anchored at the end points and middle.

Number of items.

1 item, either a VAS or a Likert scale rating.

Response options/scale.

For the VAS rating, a score of 0–10 (down to 1 decimal place) is used, and for the Likert scale, a Medical Research Council grade of 0 (no disease damage), 1 (mild disease damage), 2 (moderate disease damage), 3 (severe disease damage), or 4 (extremely severe disease damage) is used. The 10-cm VAS may have better precision, sensitivity, and specificity, but the 2 scales highly correlate (5).

Recall period for items.

The global disease damage score is based on a current assessment, although a recall period of up to 2–4 weeks for the components of global disease damage is acceptable.

Endorsements.

The physician global disease damage has been recommended to be included in the assessment of damage for adult and juvenile patients with polymyositis (PM), dermatomyositis (DM), and inclusion body myositis (IBM) by the International Myositis Assessment and Clinical Studies Group (IMACS) (1), and achieved consensus to be included as a core set measure of disease damage for patients with juvenile DM by the Paediatric Rheumatology International Trials Organisation (8).

Examples of use.

Natural history studies, particularly those validating the Myositis Damage Index (MDI) and other damage assessments (27, 34), as well as several myositis therapeutic trials that have recently completed enrollment.

Practical Application

How to obtain.

The physician global damage assessment is available in publications using this as an assessment tool, free of charge (5). The IMACS web site (http://www.niehs.nih.gov/research/resources/collab/imacs/diseasedamage.cfm) also hosts copies of these tools, including the grading scales and detailed instructions, along with example cases and sample ratings as training materials for physicians.

Method of administration.

The physician global damage assessment is completed by the physician assessing the patient and includes factors involving the subject's appearance, medical history, physical examination, laboratory testing, and the prescribed medical therapy.

Scoring.

A single score is derived by measuring the distance of the vertical line from the left end of the horizontal VAS. The length of the VAS should also be measured so that the score can be adjusted to a denominator of 10 cm. The Likert scale also results in a single score. Scoring takes <1 minute and is done by hand.

Score interpretation.

0 represents inactive disease, and the higher the score the more severe the disease damage.

Respondent burden.

Not applicable.

Administrative burden.

The time to complete the physician global damage assessment is <1 minute, but this requires integration with other assessment measures to derive an overall impression.

Translations/adaptations.

The physician global damage assessment has been used internationally in the native languages of the patient and examiner (8, 34). Physician global damage has been studied and used in adult and juvenile PM/DM, as well as a number of systemic rheumatic diseases.

Psychometric Information

Method of development.

Physician global damage assessment was first used in the assessment of other systemic rheumatic diseases, including systemic lupus erythematosus and systemic vasculitis. It was then adopted and studied in myositis.

Acceptability.

Missing data are not common, and floor and ceiling effects are not common. There can be measurement error if physicians do not look at their previous ratings as part of the determination of the current rating. Although based on the collection of objective data, the rating itself is subjective and based on the experience of the rater.

Reliability.
Internal consistency.

Regarding internal reliability, Spearman's correlation was excellent (Spearman's r = 0.89) for the correlation of the VAS to the Likert scale for physician global disease damage, and the intraclass correlation coefficient was 0.85 (P < 0.0001) (5).

Test–retest reliability.

Not available.

Interrater reliability.

In a study of pediatric rheumatologists assessing paper cases of juvenile DM, the κ coefficient for agreement with the Likert scale ratings of global disease damage was 0.76 and Cronbach's α was 0.98 (5).

Validity.
Content validity.

In validating the physician global activity, pediatric rheumatologists reached consensus that 4 variables (calcinosis, muscle atrophy, functional assessment, and joint contractures) were extremely important in the determination of juvenile DM global disease damage and that 16 clinical parameters were unimportant or mildly important in the assessment of damage (5).

Construct validity.

In a natural history study of juvenile PM/DM patients, the physician global damage assessment strongly correlated with the total extent and severity of damage in the MDI (Spearman's r = 0.79–0.88) (27). In the same study, which also examined treatment-refractory adult PM/DM patients, the physician global damage assessment moderately correlated with the total extent and severity of damage in the MDI (Spearman's r = 0.42–0.82) (27).

Criterion validity.

There is no gold standard upon which to assess criterion validity. Sometimes the physician global damage is used to assess criterion validity in studies validating other measures of damage.

Ability to detect change.

In the juvenile idiopathic inflammatory myopathy natural history study of patients who were reassessed 8 months after study entry, the standardized response mean for physician global damage was poor at 0.02 for the Likert scale and 0.14 for the VAS scale (5).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The data demonstrate that physician global damage is a reliable measure of damage, with some content and construct validity in juvenile (ages 2–18 years) and adult PM/DM patients, and as expected, it has little responsiveness over a relatively short period of time (8 months).

Caveats and cautions.

To reduce variability, this measure requires training of the person performing the assessment. The VAS may be subjective and somewhat dependent on the experience of the rater. Physician global damage has not been formally validated in IBM, and the validation data in PM/DM are limited.

Clinical usability.

The measure should be useful in the assessment of myositis patients, particularly for longitudinal evaluation of patients over several years. Examination of previous measurements in formulating serial ratings should help reduce measurement error.

Research usability.

Physician global assessment of damage is well suited to use in research and is becoming widely used in myositis long-term outcome studies and therapeutic trials. It is considered a core assessment of disease damage.

MYOSITIS DAMAGE INDEX (MDI)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The MDI scores damage, which is defined as persistent or permanent change in anatomy, physiology, and function that develops from previously active disease, complications of therapy, or other events (1). The MDI is patterned after the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) (55, 56) and is intended to be used in patients with adult and juvenile dermatomyositis (DM), polymyositis (PM), and inclusion body myositis (IBM).

Content.

The MDI measures specific manifestations in 11 organ systems. The MDI also includes a series of visual analog scales (VAS) to quantify damage severity in a given organ system. The MDI is structured for both pediatric and adult patients, and certain items are scored solely in each population.

Number of items.

There are 11 separate VAS ratings that constitute the MDI severity of damage scale. Individual items are assessed by the MDI extent of damage scale. There are 35 items in children, 37 in adolescents, and 38 in adults. There are also 16 optional items that require additional testing, which constitute the MDI extended damage scale.

Response options/scale.

The 10-cm VAS are anchored at the end points and the midpoint. Each of the 11 organ systems has 3–6 items scored as present or absent.

Recall period for items.

To receive a positive score, each item must be present for at least 6 months (or the pathology that led to the feature must have been present for at least 6 months) despite prior immunosuppressive or other therapy. Only items present since the date of diagnosis are included.

Endorsements.

The MDI was developed by the International Myositis Assessment and Clinical Studies Group (IMACS) and is endorsed by IMACS to measure damage as an important outcome to be assessed in myositis research studies and therapeutic trials (1). The Paediatric Rheumatology International Trials Organisation has included the MDI as part of the preliminary core set of disease damage measures for the assessment of juvenile DM (8).

Examples of use.

The MDI has been used in validation studies (14, 27, 57), as well as in long-term outcome studies (12, 34, 58, 59).

Practical Application

How to obtain.

The MDI is available on the IMACS web site (http://www.niehs.nih.gov/research/resources/collab/imacs/diseasedamage.cfm) and as part of the original publication (14). There is no cost associated with use of the paper version. The questionnaire is also available as part of the British Lupus integrated program software (39). The computer version is available from Gordon Hamilton (e-mail: gordon.hamilton@limathon.com or Limathon@aol.com), with an associated cost for commercial use.

Method of administration.

Clinician-completed, in-person administration.

Scoring.

For the VAS, scores for each organ system are determined by measuring the distance of the vertical line from the left-hand side of the horizontal VAS. The length of the VAS should also be measured so that the score can be adjusted to a denominator of 10 cm. For items in the damage index, the score is 1 point if present and 0 if absent. In order for an item to be scored as a damage item, the problem must have been present for at least 6 months and must be expected to persist or be irreversible and not treatable with immunosuppressive medication.

Score interpretation.

The VAS are summed together for a potential score of 0–110 for the MDI severity of damage score. For each organ system, 0 = no damage and 10 = extremely severe damage. For the individual items, these are summed together to comprise the extent of damage score, with ranges of 0–35 in children, 0–37 in adolescents, and 0–38 in adults. The optional items comprise the MDI extended damage score, and these are summed together for a potential score range of 0–16. Missing items are scored as not assessed. The clinical meaning of MDI scores has not been established.

Respondent burden.

Not applicable.

Administrative burden.

A complete history and physical examination are needed. The rate-limiting factor is the accessibility to previous notes (paper or electronically obtained). To complete the form for a patient who is essentially well, scoring will take <1 minute. For a complex patient not known to the physician, it may take 20–30 minutes. Some training in the use of the tool is advisable. The IMACS web site provides some training materials, with sample cases and ratings, as well as a slide collection for the cutaneous manifestations of damage.

Translations/adaptations.

The MDI is available only in English. The MDI has been used in patients with adult and juvenile PM/DM.

Psychometric Information

Method of development.

The MDI was modified from the SDI (55, 56). A 10-cm VAS for each organ system was also included to measure severity of damage. The draft version of the MDI, including the glossary, was commented on and further refined by >75 members of IMACS using a Delphi approach. Two interrater reliability exercises using adult and juvenile PM/DM patients were performed that resulted in further refinement of the tool based on feedback in ease of use and understanding of the experienced adult and pediatric specialists who participated (14).

Acceptability.

Missing data are common in the MDI extended damage score, and that portion of the tool has not been formally validated. There are no known floor or ceiling effects, and in fact, most patients with adult and juvenile PM/DM have measurable damage several years after diagnosis (12, 27, 34, 57–59).

Reliability.
Internal consistency.

In studies of juvenile and adult PM/DM, total MDI extent and severity of damage scores were highly correlated (Spearman's r = 0.87 in juvenile and 0.75–1.0 in adult PM/DM) (27, 57).

Intrarater reliability.

Not available.

Interrater reliability.

In a study of adult patients with PM/DM, the reliability was considered good (with an intraclass correlation coefficient [ICC] of >0.65 or the ratio of the estimates of the standard error attributable to the physicians to the standard error attributable to the patients <0.40) for each organ system of the MDI extent and severity scores, except for the gastrointestinal and pulmonary systems for extent of damage and the skeletal system for severity of damage (14). Good interrater reliability for most organ systems was confirmed in a subsequent multicenter study of adult PM/DM, where the ICC values for the MDI severity and extent of damage scores ranged from 0.65–0.84, except for the gastrointestinal, cardiac and peripheral vascular, and malignancy systems, where the ICCs ranged from 0.20–0.56 (12).

Validity.
Content validity.

Content validation is described above in Method of development.

Construct validity.

In a study of juvenile and adult patients with PM/DM, total MDI extent and severity of damage scores highly correlated with physician global damage (Spearman's r = 0.79–0.88). In juvenile patients with PM/DM, MDI severity of damage, as well as the muscle and skeletal system scores, also correlated moderately with the Childhood Health Assessment Questionnaire as a functional disability measure, with Manual Muscle Testing as a measure of strength, with the T1-weighted magnetic resonance imaging (MRI) score, and inversely with serum creatinine (Spearman's r = 0.37–0.58). These findings were replicated in additional studies of juvenile DM (12, 58). In adult patients with PM/DM, only serum creatinine and T1-weighted MRI correlated with the muscle system severity of damage score (12). In adult PM/DM patients, there was moderate correlation of most organ systems between the MDI and the Myositis Intention to Treat Activities Index (Spearman's r = 0.33–0.73 for muscle, cutaneous, gastrointestinal, and pulmonary systems) and lower correlation in cardiac and skeletal systems (Spearman's r = 0.13–0.24) (57).

Criterion validity.

In patients with adult or juvenile PM/DM, those with a chronic illness course had a higher rate of damage accumulation than those with a monocyclic or polycyclic course, and the percentage of patients with measurable damage was also greater in those with a chronic illness course (27). This finding was replicated in a large international study of juvenile DM (34). Adult patients with PM/DM who died had higher damage scores at last followup, including in the cardiovascular and pulmonary systems, than patients who remained alive (27).

Ability to detect change.

In adult patients with PM/DM who had treatment-refractory disease, there was a measurable increase in the annual change in the total MDI severity of damage score, with a median increase of 2.4 points (whereas the annual rate of change in the total MDI extent of damage score was undetectable, median 0) (27). Patients with juvenile PM/DM, at a median of 80 months from diagnosis, had no detectable annual rate of increase in their damage scores (27). In juvenile DM patients close to the time of diagnosis, the mean increase in the MDI extent of damage score was 0.01 per 6 months in the 6 months after diagnosis (58). In 1 cohort of juvenile DM patients, MDI extent of damage scores improved in 65% of patients at last followup (59).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The MDI offers a comprehensive assessment of the potential consequences of having myositis, complications of treatment associated with myositis, and other potential contributions to morbidity. The MDI is constructed to measure both severity and extent of damage. From the preliminary validation studies, the severity of damage score might be more sensitive in detecting damage and more sensitive to change. Although the 2 scores correlate highly, it is recommended that both measures be used simultaneously. The MDI has good reliability, good construct validity, and excellent criterion validity in juvenile (ages 3–18 years) and adult PM/DM.

Caveats and cautions.

The MDI does not measure only damage related to disease, but it also captures other comorbid conditions. Although damage scores are meant to reflect irreversible changes, improvement in some damage elements has been reported in children with juvenile DM. It is unclear whether the presence of an element for 6 months is long enough for it to represent damage or whether it might still be part of active disease, especially early in the course of illness. Training in the use of the tool and experience with myositis patients clearly improve the reliability. Examination of previous severity of damage VAS scores should reduce measurement error on serial evaluation. The VAS may be subjective and somewhat dependent on the experience of the rater. Although the MDI is recommended for use in patients with IBM, it has not been formally validated in this subgroup.

Clinical usability.

The MDI may be useful to track damage and affected organ systems over time, but the scores have no determined clinical meaning.

Research usability.

The MDI may be used in long-term observational studies or in clinical trials, mainly to see that patients treated with a new immunosuppressive therapy do not have increased damage over time. Certain novel therapies may be directed toward specific treatment of damage elements (such as treatment of calcinosis or muscle regenerative therapies), in which case the MDI can be an important outcome measure for such trials.

QUANTITATIVE MUSCLE TESTING (QMT)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

To measure the amount of maximum isometric force generated from a muscle group using specialized equipment.

Content.

In inclusion body myositis (IBM) studies, the following muscle strength measurements are typically tested: bilateral elbow flexion and extension, bilateral knee flexion and extension, bilateral ankle dorsiflexion, and bilateral grip strength.

Number of items.

This ranges from 6 muscle groups tested bilaterally to 20 muscle groups tested bilaterally (creating 12–40 individual items). The individual muscle group results can be averaged across all muscle groups tested to create a composite score, which can then be converted to a Z score.

Response options/scale.

In kilograms, with a range of up to 100 kg for each muscle group tested. Response is based on the strength of the muscle group being tested and the maximum load allowable on the tensiometer (100 kg).

Recall period for items.

None.

Endorsements.

None.

Examples of use.

There have been several phase II trials of interferon-β for IBM (10, 60), an ongoing phase II trial of arimoclomol in IBM (http://clinicaltrials.gov/ct2/show/NCT00769860), an etanercept in dermatomyositis (DM) trial (http://clinicaltrials.gov/ct/show/NCT00282880), an etanercept trial in IBM (61), an oxandrolone trial in IBM (62), intravenous immune globulin trials for IBM (63, 64), and an alemtuzumab trial in IBM (65). Rose et al (66) conducted a prospective natural history trial that showed a 4% mean decline in composite strength score from baseline over 6 months. There are no validation studies of QMT in IBM, and a single validation study of handheld pull gauge to measure isometric dynamometry in polymyositis (PM)/DM patients (67).

Practical Application

How to obtain.

QMT equipment for fixed-strength measurement can be purchased online at www.aeverl.com. The fixed device contains a tensiometer that the subject pulls against. The tensiometer is connected to a Zimmer frame device attached to an adjustable bed.

Method of administration.

The position of the patient depends on the muscle group being tested. A strap is placed distal to the movement being tested. This strap is connected to the tensiometer, which is attached to a fixed location (i.e., Zimmer frame). There is tension in the strap and the tensiometer. The joint tested is placed in midrange position. The patient is asked to pull as hard as they can. There should not be any movement in the joint being tested (isometric force). For instance, for knee flexion and extension, the subject is sitting, and the knee is in 90° of flexion, with the strap at the ankle, above the lateral malleolus. If testing flexion, the strap is hooked to the tensiometer so that the patient can attempt to bend the knee. The patient has to be stabilized. A handheld pull gauge device is also available (67).

Scoring.

Results range from 0–100 kg for each muscle group tested. A patient's log(QMT score) for a particular muscle group is standardized by subtracting his or her predicted score in the appropriate model, given the patient's age, sex, and height, and dividing by the SD around the fitted model (68). The resulting measurement can be interpreted as the number of SDs from average normal strength, after accounting for age, sex, and height. A composite QMT score for a patient is formed by averaging the standardized QMT scores across all muscle groups tested (69).

Score interpretation.

Normative data have been obtained by recruiting from hospital personnel and family members as well as family members of amyotrophic lateral sclerosis (ALS) patients. The standardization process involved constructing regression models for the relationship between log(QMT score) and age, sex, and height among normal subjects for each muscle group separately (69). Normative data using other equipment systems are also available (70, 71).

Respondent burden.

Depends on the strength, fatigability, and effort of the patient.

Administrative burden.

Up to 1 hour to test multiple muscle groups. Testing 1 or 2 muscle groups using a handheld device can take 15 minutes.

Translations/adaptations.

Has been widely used in patients with IBM, with limited reliability data in adult DM and PM. It has also been widely used in other muscle diseases, such as muscular dystrophies and ALS.

Psychometric Information

Method of development.

It was derived from studies of muscle strength deterioration over time in ALS.

Acceptability.

Missing data are common. If a muscle group is missed due to an injury, the missing data are imputed in an intent-to-treat analysis that averages the values from the visit before and after the missing time point. The floor effect can be present in weaker patients: are they able to actively position the joint in the position to be tested or maintain that position until the test is completed? The ceiling effect is determined by the amount of strength the tensiometer can withstand.

Reliability.
Internal consistency.

There have been no internal consistency studies conducted in ALS or patients with myositis.

Test–retest reliability.

In ALS, the intrarater test–retest correlation was 0.96 for normal controls and 0.98 for ALS patients. The mean absolute percent variation of testing and retesting was 6.5% for normal subjects and 8.9% for ALS patients (70). In Duchenne's muscular dystrophy (DMD), intrarater test–retest correlations ranged from 0.88–0.99 for children with DMD and from 0.85–0.98 for children without DMD (72). Interrater reliability ranged from 0.81–0.98 by analysis of variance (ANOVA) in a study of 13 muscle groups tested by a handheld pull gauge in patients with stable PM/DM (67). No studies have tested the reliability of QMT in patients with IBM.

Interrater reliability.

The mean interrater test–retest correlation was 0.95 for normal controls and 0.98 for ALS patients. The absolute mean percent variation between QMT trials is 7.6% for healthy subjects and 8.2% for ALS patients (73). Interrater test–retest correlations ranged from 0.74–0.97 in children with DMD and from 0.71–0.98 in children without DMD (73). These numbers are similar in subjects with facioscapulohumeral dystrophy (FSH) (69). Intrarater reliability ranged from 0.88–0.98 by ANOVA in a study of 13 muscle groups tested by a handheld pull gauge in patients with stable PM/DM (67). No studies have tested the reliability of QMT in patients with IBM.

Validity.
Content validity.

No studies have been done to show validity in patients with PM, DM, or IBM.

Construct validity.

In FSH, the correlation between the composite QMT score and Manual Muscle Testing (MMT) scores was strong (r = 0.88) (69). QMT was shown to correlate strongly with the Inclusion Body Myositis Functional Rating Scale (Pearson's correlation coefficient at baseline = 0.73 and then at 24 weeks = 0.80) (74).

Criterion validity.

There is no criterion validity available in PM, DM, or IBM patients.

Ability to detect change.

In FSH, both the QMT (P = 0.04) and MMT (P = 0.05) were able to detect changes in strength over time (69). Rose et al (66) demonstrated in a natural history study that the mean ± SD decline in composite strength score from baseline was 4% ± 5.8% over 6 months (P = 0.05), but that the rate of progression was variable and that 4 of the 11 subjects involved did not show any decline. Dalakas et al (75) reported a 14.9% in decline in strength in the Alemtuzumab (CAMPATH 1-H) study. The standardized response mean is not available for patients with myositis.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

Isometric dynamometry provides a quantitative measure that might be sensitive in detecting small changes in strength as well as mild weakness that might not be detected by MMT.

Caveats and cautions.

The person administering the test must be trained. There are many different instruments (hardware and software) to measure quantitative muscle strength. Some require more training than others. Also, depending on the unit, it may need a dedicated room to house the equipment. QMT is difficult to use on patients who have trouble moving or have less than antigravity strength. The cost of equipment can run to ∼$15,000. Like other measures of strength, QMT does not discriminate between activity and damage and may diminish in sensitivity and specificity as an activity measure for patients who are farther along in their illness course with accumulated damage and progressive muscle atrophy. There is almost no validation in patients with myositis, including limited reliability data in adult PM/DM and limited construct validity in IBM patients. There are no data using QMT in juvenile idiopathic inflammatory myopathy patients.

Clinical usability.

It takes ∼1 hour to test a full set of muscle groups; therefore, it is not a good tool to use during routine clinic visits.

Research usability.

QMT is difficult to use due to cost, training, and retraining of study personnel. QMT has been successful as an end point in IBM trials in detecting significant drug effects (62, 75).

MYOSITIS FUNCTIONAL INDEX-2 (FI-2)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The FI-2 was developed as a disease-specific observational tool for adult patients with polymyositis (PM)/dermatomyositis (DM) to measure muscle endurance (76). The FI-2 is a more developed version of the original Functional Index (FI), which was presented in 1996 as the first disease-specific muscle impairment measure for patients with PM/DM (77).

Content.

The FI-2 measures the number of repetitions performed in 7 muscle groups: shoulder flexion, shoulder abduction, neck flexion, hip flexion, and knee extension (step test; performed at a pace of 40 beats per minute, which is monitored by a digital metronome), and heel lifts and toe lifts (performed at a pace of 80 beats per minute). Each muscle group is scored as the number of correctly performed repetitions, with no total score, presenting a profile of muscle impairment for the upper and lower extremities and the neck.

Number of items.

If the assessment is performed on both the right and left extremities, the FI-2 consists of 11 items, and when it is performed on the dominant body side, there are 7 items. There is no total score.

Response options/scale.

Each muscle group is scored by the number of repetitions performed, and the score ranges from 0–60 for the shoulder flexion, shoulder abduction, neck flexion, hip flexion, and step test tasks, or from 0–120 for the heel and toe lifts.

Recall period for items.

The patient performs the test and is observed and scored by a trained health professional. There is no recall period.

Endorsements.

None.

Examples of use.

The FI-2 is used in clinical practice in Sweden to measure muscle endurance of adult PM/DM patients at yearly followup visits and to assess changes after interventions such as exercise or medical treatment. The FI-2 has been used in 1 study evaluating a 7-week intensive resistance training program for patients with chronic PM/DM (78).

Practical Application

How to obtain.

The protocol of the FI-2 and written instructions can be obtained at no cost in the original publication (76). The tool, as well as an instructional slide set and video, can be found on the International Myositis Assessment and Clinical Studies Group web site (http://www.niehs.nih.gov/research/resources/collab/imacs/main.cfm).

Method of administration.

The FI-2 is a direct observational assessment tool.

Scoring.

The number of correctly performed repetitions is recorded, together with the perceived muscle exertion for each task. Computer scoring is not necessary.

Score interpretation.

The number of correctly performed repetitions is scored for each muscle group; they vary from 0–60 or 0–120, where 0 = severe limitation and 60 (or 120) = no limitation. After each muscle group is tested, the patient rates his/her perceived muscle exertion according to the Borg CR-10 scale, which ranges from 0–10, where 0 = no exertion and 10 = extremely strong, almost maximal exertion (79). The Borg CR-10 scale is not included in the FI-2 but is used to measure how much effort the patient exerts to complete each task. This enhances the observer's ability to detect whether the patient stops due to reasons other than muscle fatigue, such as pain or lack of motivation. To date, normative data are not available for the FI-2.

Respondent burden.

Not applicable.

Administrative burden.

The maximal time required to perform each muscle group is 3 minutes, and the maximal time to perform the FI-2 on both the right and left sides is 33 minutes. If the FI-2 is performed only on the dominant side, the time required is 21 minutes. The ratings of perceived exertion (the Borg CR-10) add an additional minute. The FI-2 takes ∼5 minutes to score, and no training is required for scoring. In some centers, the FI-2 is performed in a separate session by a trained physical therapist.

Translations/adaptations.

No translations or cultural adaptations are currently available. The tool has not yet been tested in other populations, only in adult PM/DM, with unpublished clinical observations in patients with inclusion body myositis (IBM).

Psychometric Information

Method of development.

The FI-2 was based on the previous version, the FI, which was also developed specifically for patients with PM/DM (77). The FI assessed the number of repetitions (maximal number of repetitions, range 10–20) in elbow flexion, shoulder flexion, shoulder abduction, neck flexion, trunk flexion (sit-up), hip flexion, knee extension (step test) as well as heel lifts, and toe lifts performed standing on 1 leg at a time. The FI also included tests of grip strength using the Grippit instrument (80), ability to transfer from side to side and up to a sitting position, as well as peak expiratory flow. Patients and health professionals were involved in the validation process. Due to ceiling effects and problems with internal consistency with several items in the FI (discussed below), a group of health professionals and patients agreed to remove hip abduction, transfers, and peak expiratory flow from the tool when the FI-2 was created (76). Despite ceiling effects, the neck flexion and sit-up tasks were considered relevant. All tasks of the FI were functional tasks except for the grip strength, so the Grippit assessment was excluded from the FI-2, but it is recommended that it be assessed as a separate measure. The number of repetitions was increased to 60 or 120 for each task, and the dorsal and plantar flexion tasks were revised to be performed standing on both feet instead of balancing on 1 foot. To further ensure stability to the tasks, repetitions are performed at a specific pace guided by a metronome.

Acceptability.

For the FI (version 1), ceiling effects, defined as the median value equaling the maximal score for each muscle group, were evident for 8 of the 11 muscle groups, the transfers, and the peak expiratory flow (76). No floor or ceiling effects have been found in patients with PM/DM with the FI-2, and the mean number of repetitions for each item varies from 60–120 in patients with PM/DM (76). However, clinical practice indicates that there might be floor effects when used in patients with IBM, especially the knee extension, the heel lift, and the toe lift tasks. There are generally no missing data with the tool, and if the patient will not attempt a particular item, the score is 0 on that item.

Reliability.
Internal consistency.

Because each muscle group is scored individually and not included in a subscale, internal consistency analysis is not relevant for the FI-2.

Test–retest stability.

The measurement error for each task varies between 5 and 16% (76).

Rater reliability.

The FI-2 demonstrated good to excellent intrarater reliability for all tasks, with intraclass correlation coefficients (ICCs) for the 7 tasks varying between 0.75 and 0.99 (76). Systematic variations were revealed for the shoulder flexion task, indicating that a training session for the patient is necessary to ensure good intrarater reliability. Interrater reliability was also good to excellent, with ICC coefficients of 0.86–0.99 for the tasks without systematic variation. It is advised that the assessor train on how to score the tasks on at least one previous occasion to ensure good interrater reliability (76).

Validity.
Content validity.

To establish content validity, repeated administrations of the FI from patients with adult PM/DM were analyzed for floor and ceiling effects as well as for internal redundancy and consistency. No tasks were redundant, but grip strength, neck flexion, and trunk flexion (sit-up) showed poor internal consistency with other upper extremity tasks. These results were discussed with a group of health professionals and patients, and hip abduction, transfers, and peak expiratory flow were removed due to ceiling affects and lower relevance. Despite ceiling effects and poor intra- and interrater reliability, the neck flexion was considered relevant and remains in the tool.

Construct validity.

The shoulder flexion task correlated moderately with the shoulder flexion isokinetic muscle endurance test (Spearman's r = 0.58) and less with other measures, confirming that the FI-2 assesses muscle endurance in patients with adult PM/DM (76). The knee extension task of the FI-2 (step test) correlated moderately with maximal isokinetic strength of the knee extensors (Spearman's r = 0.42), less with other constructs, and not at all with the isokinetic knee extension endurance test (76). This lack of correlation could be because the step test is performed in a closed-chain movement that also stresses the cardiovascular system, whereas the isokinetic test is open chained.

Criterion validity.

There is no gold standard by which to assess criterion validity.

Ability to detect change.

Statistically significant improvements were detected in the shoulder flexion task on the right and left sides after a 7-week intensive training program in adult patients with chronic PM/DM (78), with standardized response means between 0.20 and 1.01 for the different components of the FI-2. This study also reported clinically relevant improvements of at least 20% in several of the FI-2 tasks.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The FI-2 assesses muscle endurance, which seems to be an important limitation for patients with PM/DM (81). There is good content validity and reliability and moderate construct validity in patients with adult PM/DM.

Caveats and cautions.

The FI-2 takes a rather long time to perform, and further research is needed to establish sensitivity and specificity to change after rehabilitation interventions or medical treatment. Like all other measures of function in myositis, the FI-2 does not discriminate between activity and damage and may diminish in sensitivity and specificity as an activity measure for patients who are farther along in their illness course with accumulated damage and progressive muscle atrophy. Clinical experience indicates that there may be floor effects for several tasks of the FI-2 when used in patients with IBM, although this needs formal evaluation. The FI-2 has been formally tested in adult PM/DM patients, used in IBM patients clinically but not reported on, and has not yet been tested in juvenile myositis.

Clinical usability.

While the tool has good psychometric properties in patients with PM/DM, the clinical meaning of scores has not yet been established, making this tool difficult to apply to the care of individual patients. If physical therapists or other personnel are not available to perform the test, the length of time needed to perform the FI-2 is a limiting factor for clinical use. Therefore, a streamlined version of the FI-2 is being developed.

Research usability.

The FI-2 has sound content and construct validity and reliability properties in patients with adult PM/DM. The extended numbers of repetitions confirm that the FI-2 assesses muscle endurance, although it was not proven for the knee extension task, which correlated best with isokinetic muscle strength. Additional studies on sensitivity to change and specificity and application to other subgroups of myositis are needed.

MYOSITIS ACTIVITIES PROFILE (MAP)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

To assess disease-specific limitations of activities of daily living in patients with polymyositis (PM)/dermatomyositis (DM).

Content.

The MAP includes 4 subscales (movement activities, activities of moving around, personal care, and domestic activities) and 4 single items (keep in touch with close friends and relatives; avoid overexertion during daily activities; be able to cope with work, studies, and/or housework to a satisfactory degree; and be able to do recreational activities of choice) (24). Subscales and single items are based on the activity domain of the revised International Classification of Impairments, Disability and Handicaps (ICIDH-2) Beta-2 draft (82).

Number of items.

The MAP includes 31 items.

Response/option scale.

Each item is scored on a 7-point Likert scale from 1–7, where 1 = no trouble to do and 7 = impossible to do.

Recall period for items.

During the last week.

Endorsements.

None.

Examples of use.

The MAP was developed for patients with adult PM/DM and is currently used in clinical practice to evaluate changes after rehabilitation interventions in several rheumatology clinics in Sweden. It is also used in yearly followup visits at the Karolinska University Hospital. The MAP has been used in 1 clinical exercise study.

Practical Application

How to obtain.

The MAP can be obtained in English at no cost in the original publication (24) or in Swedish or English by contacting the author (e-mail: helene.alexanderson@karolinska.se) at the Karolinska Institute, Stockholm, Sweden.

Method of administration.

The MAP is a self-administered questionnaire.

Scoring.

The 4 subscales are scored as the median value of item responses within the subscale. For the subscales movement activities (n = 8 items), moving around (n = 4 items), and domestic activities (n = 6 items), the median value is the lower of the 2 middle values. The subscale personal care (n = 9 items) is scored as the median value. The 4 single items are scored as the actual item response value. In case of missing values that result in an odd number of items in a subscale, the score is the middle value. In case of missing values resulting in an even number of items, the subscale is scored as the lower of the 2 middle values.

Score interpretation.

1 = no difficulty to do and 10 = impossible to do. No cut points have been identified, and normative data are not available.

Respondent burden.

The MAP takes 5–10 minutes to complete, with low item difficulty.

Administrative burden.

The MAP takes 5 minutes to score by hand.

Translations/adaptations.

The MAP has been translated from Swedish into American and British English, and adaptations to the North American and British cultural contexts are ongoing. Only patients with adult PM/DM have been studied to date.

Psychometric Information

Method of development.

The items and subscales of the MAP were developed based on the revised ICIDH-2 Beta-2 draft published in 1999 (82). The activity domain of the ICIDH-2 Beta-2 draft included 315 activities classified into the following 8 categories: activities of learning and applying knowledge, communication activities, movement, activities of moving around, self-care activities, domestic activities, interpersonal activities, and performing tasks and major life activities. Eighty-one of these activities from the 6 latter categories were considered by the research group to be relevant for individuals living in Europe. Items were discussed within the research group, and strategically chosen patients with different sexes, diagnoses, disease activity and durations, family situations, and working statuses were invited to rate both the difficulty and importance of items. Ten strategically chosen patients (cohort 1) rated difficulty and importance of the 81 items on a 10-cm visual analog scale (VAS). Questions about sexual activities were rated as limited and very important by cohort 1, but a majority of patients in cohort 2 who filled out the MAP for analysis of internal redundancy and consistency chose not to fill out these questions. Therefore, questions about sexual activities were removed, and the 4 remaining items were listed as single items (24).

Acceptability.

Before completing the MAP, patients are asked to decide both how difficult each activity is to perform in daily life and how important it is to be able to perform the activity in daily life. No study to evaluate whether patients can weigh both aspects equally has been carried out. Missing values are rare. No floor or ceiling effects have been detected in the Swedish context (24).

Reliability.
Internal consistency.

Ten strategically chosen patients with adult PM/DM (cohort 1) rated the difficulty and importance of the 81 items on a 10-cm VAS. Spearman's correlation coefficients ranged between 0.61 and 0.91 in testing the internal consistency of subscales (24). There was poor internal consistency between items in the interpersonal activities and performing major life activities subscales.

Test–retest reliability.

Weighted κ coefficients for test–retest reliability ranged between 0.56 and 0.76 for subscales and between 0.65 and 0.77 for single items without systematic variations in 17 stable adult PM/DM patients (24).

Validity.
Content validity.

See above in Method of development.

Construct validity.

The third version of the MAP correlated highly with the Health Assessment Questionnaire (Spearman's rank correlation = 0.70), but correlated moderately with measures of muscle impairment (Spearman's r = 0.55) and well-being (Spearman's r = 0.43), and poorly with global disease activity (Spearman's r = 0.17) in patients with adult PM/DM (24). Moderate correlations (Spearman's rank correlation = 0.51–0.71) were found between the MAP subscales and single items and the subscales of the Arthritis Impact Measurement Scale (24).

Criterion validity.

There is no gold standard by which to establish criterion validity in activity limitation measures.

Ability to detect change.

The Swedish MAP has been used as a measure of activity limitation in a 7-week intensive resistance training study that did not reveal statistically significant changes on a group level after short-term exercise therapy in adult PM/DM patients (78). The standardized response mean ranged between 0.15 and 1.32 for the subscales and between 0.20 and 0.41 for the single items.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The MAP is a disease-specific measure of daily life functions, including aspects of both difficulty of the task and importance of the activity. Patients were involved in the development of the tool. There is moderate reliability and moderate construct validity in patients with adult PM/DM.

Caveats and cautions.

The MAP needs to be translated to other languages and adapted to other cultural contexts before it is used in clinical practice and research. Information on sensitivity to change and specificity is very limited, and data currently exist for adult PM/DM but not other myositis subgroups. Its applicability to children has also not been examined. Like all other measures of function in myositis, the MAP does not discriminate between activity and damage, and may diminish in sensitivity and specificity as an activity measure for patients who are further along in their illness course with accumulated damage and progressive muscle atrophy. There are no data on the MAP in patients with inclusion body myositis or juvenile idiopathic inflammatory myopathy.

Clinical usability.

The low patient and administrative burden and ensured item relevance support its use in clinical practice in Sweden, but the limited language and adaptation availability as well as the lack of cut points and error of measurement are important limitations. The clinical meaning of scores has not yet been established, making this tool difficult to apply to the care of individual patients.

Research usability.

The thorough content validity process supports the relevance of items of the MAP, the construct validity analysis shows that the MAP assesses activity limitation, and the acceptable test–retest reliability supports the use of the MAP in research in patients with adult PM/DM. Further research is needed to establish sensitivity to change and specificity and to examine the performance of the MAP in other subgroups of myositis patients.

INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The IBMFRS is a 10-point disease-specific functional rating scale that is intended only for patients with inclusion body myositis (IBM) (74).

Content.

Includes swallowing, handwriting, cutting food and handling utensils, fine motor tasks, dressing, hygiene, turning in bed and adjusting covers, changing position from sitting to standing, walking, and climbing stairs.

Number of items.

10 items.

Response options/scale.

Graded on a Likert scale from 0 (being unable to perform) to 4 (normal).

Recall period for items.

Patients are asked to compare how they are at the time the questions are being asked to how they were prior to the start of the disease.

Endorsements.

None.

Examples of use.

Currently there are 2 clinical trials of interferon (10, 60) and an ongoing phase II trial of arimoclomol in IBM that are using the IBMFRS as an outcome measure.

Practical Application

How to obtain.

It is available in the original publication and in a review on IBM (74, 83).

Method of administration.

Interviewer to patient.

Scoring.

10 individual scores are added for a total score.

Score interpretation.

Score range is from 0–40, where 40 = normal function and no disability and 0 = severe functional disability. The range of scores corresponding to mild and moderate disability scores has not been determined.

Respondent burden.

15 minutes.

Administrative burden.

15 minutes.

Translations/adaptations.

Available in English only. Translations and cross-cultural adaptations are not available. This rating scale has been tested only in patients with IBM, not adult or juvenile polymyositis (PM)/dermatomyositis (DM).

Psychometric Information

Method of development.

It was modified from the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS), which was developed to allow patients to rate their muscle function, self-care, and pulmonary function (84).

Acceptability.

Missing data are not common because it is a set of questions that is asked. If a question is missed, the scores available would be added. There are no floor or ceiling effects.

Reliability.

A reliability study for IBM is in progress.

Validity.
Content validity.

The instrument was developed by neurologists, clinical evaluators, and the research coordinators in the Muscle Study Group. The ALSFRS was used as the template, and several items were altered to address motor problems specific to IBM patients.

Construct validity.

The IBMFRS showed significant moderate to good correlations (Pearson's correlation coefficients 0.55–0.86) with maximal voluntary isometric contraction, Manual Muscle Testing, handgrip dynamometry, and the ALSFRS in IBM patients (74).

Criterion validity.

There are no criterion validity results available for the IBMFRS.

Ability to detect change.

This instrument was shown to be able to detect change in a 24-week trial of interferon-β for IBM, with an effect size of −2.9 (74).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The instrument does measure important elements of functional disability for patients with IBM. It is quick, inexpensive, and easy to administer. It does not require any special equipment or training.

Caveats and cautions.

The clinician asks the patient to compare how they are today with how they were before the start of the disease. Some IBM patients have had the disease for decades. For them it might be harder to remember their state before disease onset. Also, as people get older, they tend to lose function in the hand or get arthritis (harder to use keys, pick up objects). It can be difficult to separate normal aging processes from IBM-related processes. Like all other measures of function in myositis, the IBMFRS does not discriminate between activity and damage, and may diminish in sensitivity and specificity as an activity measure for patients who are farther along in their illness course with accumulated damage and progressive muscle atrophy. Further validation of the IBMFRS is needed, particularly for patients with IBM. The IBMFRS has not been developed for or tested in patients with adult or juvenile PM/DM.

Clinical usability.

The IBMFRS should be a valuable clinical tool, since it is quick and easy to administer.

Research usability.

It is easily incorporated into IBM research protocols. It is the only IBM-specific outcome measure based on subject responses.

CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The CDASI is a clinician- or clinician–investigator-scored instrument that separately measures activity and damage in the skin of dermatomyositis (DM) patients (7, 85). Because it is a 1-page instrument with common and responsive elements, it is feasible to use in daily clinical practice for monitoring DM skin disease. There is a modified CDASI (version 2), which is the one in current use (85). This modified version further simplifies the original CDSAI by combining ulceration and erosion into 1 category, simplifies descriptors for Gottron's damage and nailfold changes, and eliminates excoriation as a subscale (85).

Content.

The modified CDASI has 3 activity measures (erythema, scale, and erosion/ulceration) and 2 damage measures (poikiloderma and calcinosis). In addition, Gottron's papules on the hands are evaluated in terms of activity (erythema, ulceration) and damage (dyspigmentation or scarring). Lastly, activity in terms of periungual changes and alopecia is measured.

Number of items and subscales.

Each of the 3 activity scales (erythema, scale, and erosion/ulceration) and 2 damage measures (poikiloderma and calcinosis) is assessed over 15 body areas; the worst level of activity is scored, whereas the damage measures are scored for their presence or absence. In additon, Gottron's papules are evaluated in terms of activity (erythema or ulceration) and damage (dyspigmentation or scarring). Lastly, activity in terms of periungual changes and alopecia is measured.

Response options/scale.

Disease activity is assessed by the worst degree of erythema (1 = pink, 2 = red, 3 = dark red), scale (1 = scale, 2 = crust, lichenification), and the presence of erosions or ulceration (scored as present or absent) in 15 different anatomic locations. Periungual changes are scored from 0–2, where 0 = no periungual changes, 1 = periungual erythema, and 2 = visible telangiectasias. Alopecia is scored present or absent, where 0 = no alopecia and 1 = presence of alopecia in the past 30 days. Gottron's sign on the knuckles is assessed similarly to the erythema scale used in other anatomic locations. When Gottron's papules are present, the erythema score obtained on the knuckles is doubled. Disease damage is assessed by the presence or absence of poikiloderma or calcinosis in the 15 different anatomic locations. In additon, damage in areas of Gottron's sign on the hands is assessed (1 = dyspigmentation, 2 = scarring).

Recall period for items.

Current examination, except for alopecia that may be present over the past 30 days.

Endorsements.

None.

Examples of use.

The modified CDASI has been used in several prospective databases of adult DM patients and in 2 completed therapeutic trials.

Practical Application

How to obtain.

The CDASI is copyrighted and can only be reprinted with permission from the authors. The CDASI may be used for routine clinical use by clinicians in order to assist the clinical consultation, evaluation, and clinical decision-making process. There is no need to seek specific permission for this and there is no charge for the use of the CDASI in this context. However, it is a requirement that every copy of the CDASI should always reprint the copyright statement: “© University of Pennsylvania 2009.” There is a requirement to seek permission when the CDASI is used for research purposes. Purely academic research projects are granted use of the CDASI without charge. Please contact Dr. Victoria Werth (e-mail: werth@mail.med.upenn.edu) for permission to use.

Method of administration.

The CDASI is administered by a trained clinician while examining the patient.

Scoring.

Each item of the CDASI version 2 is scored according to the most severe lesions in a body area and on the various characteristics outlined above. The CDASI has a total score ranging from 0–132, which is divided into activity and damage subscores, which range from 0–100 and 0–32, respectively. Scoring of disease activity, as indicated on the CDASI instrument, involves adding the scores on the left half of the CDASI, i.e., erythema, scale, erosion/ulcerations, Gottron's sign, periungual change, and alopecia. Scoring of disease damage requires addition of scores on the right half of the CDASI, i.e., poikiloderma, calcinosis, and Gottron's dyspigmentation or scarring. Missing values are counted as 0.

Score interpretation.

Scores range from 0–100 for activity and from 0–32 for damage. Among the activity items, the potential range for erythema for all 15 areas is 0–45, for scale is 0–30, and for erosion/ulcerations is 0–15. The range for Gottron's erythema is 0–6, for Gottron's ulcerations is 0–6, for periungual change is 0–2, and for alopecia is 0–1. For damage items, the range for poikiloderma is 0–15, for calcinosis is 0–15, and for Gottron's damage is 0–2. Higher scores indicate greater disease activity or greater disease damage.

The level of disease activity can be interpreted as low, moderate, or high. The mean ± SD CDASI activity for mild disease was 11.4 ± 7.0, moderate was 25.6 ± 8.9, and severe was >39.4 (86). Ongoing studies are refining mild, moderate, and severe disease categories and examining the minimal clinically significant change. Scores in other populations are not available but presumably would be 0 for a healthy individual.

Respondent burden.

Not applicable.

Administrative burden.

The CDASI takes a mean of 4.8 minutes for dermatologists experienced in the assessment of dermatomyositis to complete (7); presumably less experienced physicians may take longer. Training is necessary for reliable assessment of activity and damage. A training tool is available from Dr. Werth. Scoring takes <1 minute and can be done by hand.

Translations/adaptations.

The CDASI is available in English. It has been studied and used in patients with adult classic DM, as well as with hypomyopathic and amyopathic DM, but not in other myositis subgroups.

Psychometric Information

Method of development.

Development of the CDASI has been an iterative process involving experts in rheumatologic dermatology. The CDASI was designed to capture the most important signs of activity and damage that are predominant in patients with DM and signs that would be amenable to change over time (7, 85). Dermatologists experienced in the assessment of DM thought that the CDASI was complete, and they expressed satisfaction with the measure during multi-investigator meetings and studies. Items were generated by discussion of important aspects of the disease with patients and by discussion of specific items with expert dermatologists during group meetings. Subscales were generated based on items chosen by the group during consensus meetings as important measures of cutaneous DM activity and damage, with elements of activity selected as responsive to change. The tool was modified due to the group's desire to simplify the CDASI and to better describe some of the elements of the subscales.

Acceptability.

The instrument is 1 page and easily readable. Missing data are not common, and any missing items are scored as 0. Data analyzed from a prospective database of 182 dermatomyositis assessments have not shown floor or ceiling effects.

Reliability.
Internal consistency.

Evidence for internal consistency is not currently available.

Test–retest reliability.

The CDASI had an intraclass correlation coefficient (ICC) for the CDASI activity subscore of 0.84 (95% confidence interval [95% CI] 0.70–0.98) (7). The CDASI had an ICC for the CDASI damage subscore of 0.86 (95% CI 0.75–0.98) (7). Intrarater reliability ICC for the modified CDASI activity subscore was 0.87 (95% CI 0.70–0.95), and for the modified CDASI damage subscore was 0.80 (95% CI 0.56–0.92) (85).

Interrater reliability.

The CDASI had an ICC for the CDASI activity subscore of 0.84 (95% CI 0.70–0.98) (7). The CDASI had an ICC for the CDASI damage subscore of 0.53 (95% CI 0.32–0.73) (7). Interrater reliability ICC for the modified CDASI activity subscore was 0.75 (95% CI 0.55–0.90), and for the modified CDASI damage subscore was 0.56 (95% CI 0.36–0.79) (85).

Validity.
Content validity.

Evaluation of content was considered adequate by all 10 dermatologists participating in a validation study with the modified CDASI. Content validation is described further above in Method of development.

Construct validity.

The physician global activity (Spearman's r = 0.75) and damage visual analog scales (Spearman's r = 0.90) correlate highly with the activity and damage subscores of the modified CDASI (85), and a global itch score correlates moderately (Spearman's r = 0.63) with the CDASI activity score from a study of adult DM (85). CDASI activity scores correlated moderately (Pearson's r = 0.46 for emotion, 0.44 for function, and 0.33 for symptoms) with the Skindex-29 subscores and correlated mildly but significantly with the Dermatology Life Quality Index (r = 0.29) in patients with adult DM, suggesting that increased cutaneous activity, as measured by the CDASI, correlates with a poorer quality of life.

Criterion validity.

The CDASI was found to be a significant predictor of the Likert scales for physician global activity and damage scores, which were the compared gold standards. All CDASI mean scores (total, activity, and damage) expressed statistically significant distinct values when grouped by Likert scores (mild, moderate, severe activity or damage, all P values ≤0.001) (7). The CDASI expressed a significant, near-perfect fit for linearity for activity (P < 0.001) and damage (P < 0.005), with r2 values ≥0.95 (87).

Responsiveness to change.

CDASI scores were assessed, as well as a physician global score and an overall evaluation from the physician, as to whether the patient had improved, worsened, or not changed from their previous research visit. The standardized response mean (SRM) for the largest clinical change per patient, defined as the largest difference in the physician global activity score between 2 consecutive visits, was 1.25 for the CDASI, which corresponded to an SRM of 1.03 for physician global activity (87).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The CDASI is a partially validated 1-page instrument that captures key findings regarding skin activity and damage in DM patients. It allows capture of the worst attributes of 15 body areas but does not involve measurement of body surface area (BSA). BSA is notoriously difficult to capture, particularly for a condition that may involve only small amounts of skin. The tool attempts to assess improvement within an area by providing several levels of activity for erythema, scale, and Gottron's lesions. A small modification to simplify the CDASI was shown to have equally good validity and reliability in comparison with the original CDASI. Currently the CDASI shows good reliability, good but limited construct validity, and excellent responsiveness in patients with adult DM.

Caveats and cautions.

Appropriate training on use of the CDASI is suggested to reduce variability in assessments. Definition and measurement of poikiloderma often involve a component of erythema and dyspigmentation, both of which are captured. Further studies of the CDASI are needed to determine cut points for mild, moderate, and severe skin disease activity and damage, as well as the minimal clinically significant change needed to demonstrate improvement. The instrument was designed to measure important responsive elements but was not designed to capture every element of DM skin disease. The CDASI has been used and partially validated in adult DM patients, but not in other subgroups of myositis.

Clinical usability.

Based on available psychometric data, the CDASI should be a useful measure in the clinical context. Calculation is simple, with separate determination of a total activity and a total damage score for an overall score by simply adding them. This separation of activity and damage scores prevents the potential for paradoxical stability of scores as disease activity decreases, but damage simultaneously worsens.

Research usability.

The CDASI has been useful in research assessments. The CDASI has been used in several multicenter studies to evaluate response in the skin of DM patients. Studies looking at response to therapy will likely focus on the CDASI activity assessment, which has been shown to be responsive to change.

CUTANEOUS ASSESSMENT TOOL (CAT)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The CAT was developed to comprehensively assess a wide range of cutaneous manifestations of idiopathic inflammatory myopathy (IIM) in children and adults (88). It was first published in 2007. An abbreviated version of the CAT (aCAT) was published in 2008 and is currently the preferred format (89).

Content.

Items of the CAT were chosen by expert opinion to reflect the range of both activity and damage in cutaneous lesions observed in juvenile and adult IIM.

Number of items.

The CAT consists of a skin disease activity score and a skin disease damage score. There are a total of 21 items, including 10 activity lesions, 4 damage lesions, and 7 lesions that are common to both the activity and damage scores.

Response options/scale.

In the original CAT, each lesion is scored depending on various characteristics (e.g., erythema, scaling). For the aCAT, each item is either present or absent.

Recall period for items.

Scoring of the CAT requires that the lesion be observed at the time the CAT is administered (i.e., no recall period).

Endorsements.

None.

Examples of use.

The CAT has been used to date in studies that have examined its psychometric properties (7, 87–90).

Practical Application

How to obtain.

The CAT is available from the Rheumatology web site (posted as supplementary material) (88) and on the International Myositis Assessment and Clinical Studies Group web site (http://www.niehs.nih.gov/research/resources/collab/imacs/othertools.cfm).

Method of administration.

The CAT is administered by a trained clinician while examining the patient.

Scoring.

Each item of the CAT is scored depending on the presence of the lesion and on various characteristics (e.g., erythema, presence of scaling, crusting, or erosions, and presence of ulcerations or necrosis). Scores for each item range from 0–2 to 0–7. For the aCAT, items are scored as 1 if present and 0 if absent.

Score interpretation.

For the original CAT, the total skin disease activity score ranges from 0–96, and the total skin disease damage score ranges from 0–20. For the aCAT, the total skin disease activity score ranges from 0–17, and the total skin disease damage score ranges from 0–11. A score of 0 reflects the absence of cutaneous manifestations. When compared to a 5-point ordinal scale for disease activity and damage, median (25th to 75th percentiles) CAT activity scores, corresponding to “no evidence of skin disease activity,” “mild,” “moderate,” “severe,” and “very severe skin disease activity,” were 1 (0–3), 7 (4–9), 13 (10–20), 18 (12–33), and 31 (27–39), respectively. The median (25th to 75th percentiles) CAT damage scores, corresponding to “no evidence of skin disease damage,” “mild,” “moderate,” and “severe or very severe skin disease damage,” were 0 (0–1), 1 (0–2), 2 (1–4), and 5 (3–6), respectively (90).

Respondent burden.

Depending on the complexity of skin disease of a patient, the CAT takes up to 15 minutes to complete, although 1 study using dermatologists experienced in the assessment of dermatomyositis skin disease reported a mean of 5 minutes (7). The aCAT takes less time due to the removal of detailed scoring.

Administrative burden.

The time it takes to administer the CAT may be a limitation in a busy clinic. Scoring takes <1 minute and can be done by hand. Training in the administration of the CAT is preferred.

Translations/adaptations.

None available at present. The CAT has been studied and partially validated in juvenile polymyositis/dermatomyositis (DM) patients and adult DM patients.

Psychometric Information

Values of psychometric evaluations for the aCAT were nearly identical to those for the CAT (89).

Method of development.

The development of the CAT was undertaken by a group of adult and pediatric rheumatologists and a pediatric dermatologist (88). Items were chosen based on expert opinion regarding the important cutaneous lesions of IIM. Twenty-eight lesions were considered candidates, including 16 activity lesions, 5 damage lesions, and 7 lesions that represented a combination of activity and damage. This list was reviewed by a larger group of rheumatologists and dermatologists, resulting in the deletion of 5 lesions (purpura, Raynaud's phenomenon, urticaria, mucinous papules, and acanthosis nigricans) and the combination of 4 other lesions into 2 lesions (Gottron's papules with Gottron's sign, malar erythema with facial erythema). Scoring was determined by the investigators based on consensus expert opinion (88).

Acceptability.

Given that the tool is administered by the clinician, missing data are not common. Missing data are scored as 0 or absent. The length of the tool has been criticized (hence development of the aCAT).

Reliability.
Internal consistency.

When juvenile IIM patients were assessed by pediatric rheumatologists, the standardized Cronbach's α for the CAT activity score was 0.79. Individual standardized Cronbach's α scores ranged from 0.77–0.81 when each item was removed from the activity score. The standardized Cronbach's α for the CAT damage score was 0.74. Individual standardized Cronbach's α scores ranged from 0.67–0.76 when each item was removed from the damage score (90). Item-total correlations for the CAT ranged from 0.02–0.67 for the activity items and from 0.001–0.29 for the damage items. The items with low correlations were generally those present in few patients, and they improved to a minimum of 0.27 (P ≤ 0.05) for lesions with >10% endorsement. Item to domain correlations for the activity items ranged from 0.25–0.99 and increased to a minimum of 0.42 (P ≤ 0.05) for lesions with ≥10% endorsement (90). Internal consistency of the aCAT was comparable to the full CAT, with Cronbach's α of 0.76 for the aCAT activity score and 0.70 for the aCAT damage score (89).

Test–retest reliability.

In adult patients with IIM assessed by dermatologists, the CAT activity score had an intraclass correlation coefficient (ICC) of 0.74 (95% confidence interval [95% CI] 0.50–0.95), and the CAT damage score had an ICC of 0.58 (95% CI 0.27–0.89) (7).

Interrater reliability.

This was assessed by having assessors review images of typical IIM lesions. ICCs for each lesion ranged from 0.33–0.90 (90). In juvenile IIM patients seen by 2 assessors, ICCs for the total activity and total damage scores were 0.71 and 0.81, respectively. ICCs for the individual items ranged from 0.11–1.0 (88). ICCs for the aCAT were comparable (0.60 for the total aCAT activity and 0.65 for total aCAT damage) (89). In a study of adults with DM assessed by dermatologists experienced in DM, the CAT activity score had an ICC of 0.60 (95% CI 0.40–0.79), and the CAT damage score had an ICC of 0.43 (95% CI 0.22–0.64) (7). The ICC for the aCAT was 0.55 (87).

Validity.
Content validity.

This has not been formally reassessed in IIM since the original development of this tool.

Construct validity.

For children with juvenile IIM assessed by pediatric rheumatologists, the CAT activity score correlated highly with the 10-cm visual analog scale (VAS) for physician skin disease activity (Spearman's r = 0.83, P < 0.0001) and physician global disease activity (Spearman's r = 0.77, P < 0.0001), and moderately with measures of muscle strength and function (correlation with Childhood Myositis Assessment Scale = −0.48, with Childhood Health Assessment Questionnaire = 0.40, and with total Manual Muscle Testing = −0.36) (90). As expected, the CAT activity and damage scores correlated poorly with serum levels of muscle enzymes (Spearman's r = 0.03–0.13), but the CAT activity score correlated mildly but significantly with lactate dehydrogenase (0.37) (90). The CAT damage score correlated moderately with the 10-cm VAS for physician skin disease damage (Spearman's r = 0.53, P < 0.0001) and for physician global disease damage (Spearman's r = 0.52, P < 0.0001) (90).

In adult patients with DM assessed by dermatologists, the CAT activity score had a Spearman's r of −0.69 with the physician global disease activity and a Spearman's r of −0.53 with 10-cm VAS for patient global disease activity. Correlation with the global itch score was moderate (Spearman's r = 0.59). The CAT damage score had a Spearman's r of −0.47 with 10-cm VAS for physician disease damage and a Spearman's r of −0.13 for 10-cm VAS for patient disease damage (7). The aCAT was also found to correlate significantly with the physician global activity VAS in a study of adult DM patients (87).

When the scores were evaluated in relation to levels of physician global activity in adult DM patients, the patients with mild global disease activity had mean ± SD CAT scores of 8.3 ± 5.1, patients with moderate global activity had mean ± SD CAT scores of 15.2 ± 6.9, and patients with severe disease activity had mean ± SD CAT scores of 22.5 ± 7.4 (7).

Criterion validity.

There is no gold standard by which to establish criterion validity.

Ability to detect change.

In children with juvenile IIM assessed 7–9 months apart, the standardized response mean (SRM) of the CAT activity score was 0.52 (95% CI 0.32–0.72). In children with a >0.8-cm improvement in physician skin disease activity, the SRM was 0.67 (95% CI 0.42–0.92) (90). SRM values for the CAT damage score were not relevant over the duration of this study. In adult DM patients, the SRM was 0.93 in a group of patients who had exhibited change based on a physician's rating (87).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The CAT and aCAT are comprehensive measures that assess the full range of cutaneous lesions in IIM. The requirement that the patient being assessed is observed reduces the likelihood of biases in reporting. The CAT and aCAT have good reliability, construct validity, and responsiveness in patients with juvenile (ages 2–18 years) and adult DM.

Caveats and cautions.

Appropriate training is preferred to reduce variability in assessments. There are some concerns about the reliability of some items. The tool has been partially validated in juvenile IIM and adult DM, but not examined in other myositis subgroups.

Clinical usability.

Based on available psychometric data, the CAT and aCAT should be useful measures in the clinical context. The time needed to administer the full CAT may be a limitation for clinicians.

Research usability.

The CAT and aCAT should be useful in research assessments. The lack of information concerning change over time in the CAT damage score should lead to some caution if used for this purpose.

DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The DSSI assesses disease activity in skin of dermatomyositis (DM) patients. The tool is patterned after the Psoriasis Area and Severity Index (PASI) (91).

Content.

The DSSI assesses disease activity based on involved body surface area (BSA) and severity. Body area is divided into 4 parts (head, trunk, upper extremity, and lower extremity) and scored by percentage of involvement. Severity of involvement is scored for the 4 anatomic locations with 3 symptom scores (redness, induration, and scaliness). The DSSI is calculated based on the percentage BSA involved (92).

Number of items and subscales.

Each of these 4 body areas is assessed by visual inspection for redness, induration, and scaliness.

Response options/scale.

The areas involved in each of the 4 main body areas are measured on the following 0–6-point scale: 0 = no involvement, 1 = <10% involvement, 2 = 10–30% involvement, 3 = 31–50% involvement, 4 = 51–70% involvement, 5 = 71–90% involvement, and 6 = 91–100% involvement. The average redness, induration, and scaliness of the lesions in each of the body areas are scored on a 0–4-point scale (91).

Recall period for items.

Current examination. There is no recall period.

Endorsements.

None.

Practical Application

How to obtain.

This tool is available at no cost and is published (91). E-mail Dr. Joseph Jorizzo (jjorizzo@wfubmc.edu) for permission to use.

Method of administration.

The DSSI is administered by a trained clinician while examining the patient.

Scoring.

The sum of the redness, induration, and scaliness scores (maximum of 12) is multiplied by the area score for each body area (maximum of 6). These totals are normalized (10%, 20%, 30%, and 40% for the head, upper extremities, trunk, and lower extremities, respectively) and summed. The total DSSI score can range from 0–72, with higher scores representing more severe disease activity (92). There are no instructions for missing values, but these are presumably scored as 0.

Score interpretation.

When compared to the global physician activity score, the mean ± SD DSSI scores were 1.3 ± 1.5 for mild global activity, 5.4 ± 4.0 for moderate global activity, and 14.9 ± 14.1 for severe global disease activity (7).

Respondent burden.

Not applicable.

Administrative burden.

Completion takes ∼2–3 minutes for experienced dermatologists who are familiar with the tool. Training is needed, as done for the PASI in psoriasis, and can be accessed on the following web site: http://www.pasitraining.com/index.html.

Translations/adaptations.

The DSSI is available in English. It has been validated and studied in patients with adult DM, but not other myositis subgroups.

Psychometric Information

Method of development.

Initial content of the scale was validated for content by a panel of experts that included board-certified dermatologists and rheumatologists. This score is mirrored after the PASI.

Acceptability.

Given that the tool is administered by a clinician, missing data are not common. The tool is rapid to use.

Reliability.
Internal consistency.

Internal consistency has not been statistically evaluated.

Stability.

Test–retest stability has been evaluated, with intraclass correlation coefficients (ICCs) between examinations by the same observers ranging from 0.79 (95% confidence interval [95% CI] 0.34–0.95) to 0.93 (95% CI 0.87–0.99) (91, 92).

Intrarater reliability.

Intrarater reliability has been completed in adult DM or amyopathic DM, ranging from 0.79 (95% CI 0.34–0.95) to 0.89 (95% CI 0.76–0.95) (7, 92).

Interrater reliability.

The DSSI has been tested at 3 institutions, with ICCs ranging from 0.44 (95% CI 0.23–0.65) to 0.94 (95% CI 0.84–0.97) in patients with adult DM or amyopathic DM (7, 92).

Validity.
Content validity.

Content validity was evaluated by a panel of expert dermatologists and rheumatologists and found to be adequate (91).

Construct validity.

The DSSI correlates moderately with physician global disease activity (Spearman's r = 0.51–0.83) and also with pruritis (Spearman's r = 0.41–0.61) in adult DM patients (7, 92). The DSSI was also found to correlate moderately with the presence of poikiloderma (Spearman's r = 0.61–0.70) (91), although the DSSI is supposed to measure activity, and poikiloderma is typically associated with damage. In evaluation of quality of life relative to the DSSI, the Spearman's correlations were also moderate (Spearman's r = 0.41 with the Skindex-16 and 0.38 with the Dermatology Life Quality Index) in adult DM patients (92). There was no significant correlation between the DSSI and periungual capillary nailfold changes, cutaneous ulceration, calcinosis, muscle enzyme levels, or muscle strength (92).

Criterion validity.

There is no gold standard upon which to assess criterion validity.

Responsiveness to change.

In 1 study of adult DM patients who received a variety of treatments, the DSSI showed a mean change of 3.9 units after treatment (95% CI 1.0–6.9). The Spearman's correlation coefficient between the change in DSSI scores and the change in physician global activity was 0.28 (92). Additional evaluation of the responsiveness of the DSSI is not available.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

This tool is a measure of skin disease activity in DM and is based on another scale, the PASI, which has been used widely in psoriasis therapeutic trials. The measure is quick to use by experienced dermatologists. The measure has acceptable reliability and limited but moderate construct validity in patients with adult DM and amyopathic DM.

Caveats and cautions.

The DSSI is a disease activity measure that depends on assessment of BSA based on the rule of 9s. BSA can be difficult to assess reliably, particularly when only small areas are involved, as can occur in DM (93). Responsiveness to change when small areas of skin are involved will likely be difficult using a measure that depends on BSA. The DSSI does not include an assessment of damage. The tool has been used in patients with adult amyopathic and classic DM, but not in other subgroups of myositis.

Clinical usability.

The DSSI is easy to use, but psychometric properties suggest that it might be difficult to use accurately. There are no measurements of damage.

Research usability.

The usability for research depends on how extensive the disease process is. It may be difficult to demonstrate change in patients with limited BSA involvement. There is no measurement of damage.

SKINDEX

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

To measure quality of life (QOL) in different populations and detect changes over time. This is a clinically responsive measure for the effect of skin disease on patients' QOL (94–96). It has been used in acne, psoriasis, atopic dermatitis, seborrheic dermatitis, alopecia areata, vitiligo, nevi, skin cancer, cutaneous lupus, and dermatomyositis (DM), among other skin conditions (97). There are several versions, with the Skindex-29 the most utilized and validated. Initially, the Skindex was a 61-item self-administered survey that measured cognitive effects, social effects, depression, fear, embarrassment, anger, physical discomfort, and physical limitations (94). It has been modified and refined several times. The tool was shortened to 29 items, with the same reliability and validity, but with more discriminative and evaluative features (95). In 2001, the Skindex-16 was published (98). It is a sensitive, accurate, single-page survey and has 2 additional advantages compared with the Skindex-29 (98). It evaluates the most bothersome rather than the most frequent symptoms, and it has fewer items, due to less duplication of questions where most patients choose the same response. A Skindex-17 is also available, developed using Rasch analysis (99). There is experience with the Skindex-16 and Skindex-29 in patients with DM.

Content.

For the Skindex-29, each item is scored on a 5-point Likert scale: 0 = never, 1 = rarely, 2 = sometimes, 3 = often, and 4 = all the time. For the Skindex-16, each item is scored on a scale of 1 (never bothered) to 7 (always bothered). Both tools have 3 subscales (emotion, symptoms, and functioning).

Number of items and subscales.

The Skindex-29 has 30 items, 29 of which are used for scoring. Three questions were added to represent DM-specific effects, specifically 2 questions for photosensitivity and 1 question for alopecia. All responses are transformed to a linear scale of 100, varying from 0 (no effect) to 100 (effect experienced all the time). Each question and subscale ranges from 0–100 points, with higher scores indicating worse QOL.

Recall period for items.

4 weeks.

Endorsements.

None.

Practical Application

How to obtain.

There is no cost; e-mail Dr. Mary-Margaret Chren (mchren@orca.ucsf.edu) for permission to use and guidance about scoring (95).

Method of administration.

Self-administered questionnaire.

Scoring.

Individual items (1–5) are added to yield a total score for each subscale; higher scores indicate worse QOL. A composite score has not been formally studied, has no face validity, and did not fit the Rasch model (99).

Score interpretation.

Norms, as well as correlation with QOL burden in a number of different skin diseases, are available (100). For the Skindex-29, an additional study evaluated patients with a mix of diseases, with >60% of the patients having an inflammatory skin disease such as acne, psoriasis, or seborrheic dermatitis, and almost one-half of the patients graded as having at least moderate disease severity, to determine the clinical meaning of scores according to symptom severity for each of the subscales (100). This study demonstrated that the emotions subscale had a mean of 3.2 (cut point of <5) for very little disease, a mean of 16 (cut points of 6–24) for mild impact on emotions, a mean of 36.6 (cut points of 25–49) for moderate, and a mean of 62.6 (cut point of >50) for severe emotional impact. The symptoms subscale had a mean of 0.0 (cut points of 0–3) for very little symptoms, a mean of 6.6 (cut points of 4–10) for mild, a mean of 17.6 (cut points of 11–25) for moderate, a mean of 37.3 (cut points of 26–49) for severe, and a mean of 62.2 (cut point of >50) for extremely severe symptoms. The function subscale showed a mean of 0.0 (cut point of <3) for very little functional impairment, a mean of 5.3 (cut points of 4–10) for mild, a mean of 20.6 (cut points of 11–32) for moderate, and a mean of 48.6 (cut point of >33) for severe functional impairment (100).

Respondent burden.

It takes ∼5 minutes for patients to complete the questionnaire.

Administrative burden.

Time for scoring is <1 minute.

Translations/adaptations.

The Skindex is available in English, Spanish, Dutch, German, French, Italian, Arabic, and Turkish. To date, it has been studied in patients with many different skin diseases, including adult DM and amyopathic DM, as well as inflammatory, autoimmune, and other skin conditions (97, 101).

Psychometric Information

Method of scoring.

All responses are transformed to a linear scale of 100, varying from 0 (no effect) to 100 (effect experienced all the time). Therefore, each item can have a minimum score of 0 and a maximum score of 100. A scale score is the mean of a patient's responses to the items in a given scale. If responses to >25% of items are missing, the questionnaire is eliminated in research settings. If any scale has >25% of the responses missing, the scale is eliminated. Scale scores are the average of items in a given scale (no imputation). A composite score is defined as the average of all items in the instrument. Any patient for whom all 3 scales are missing should be eliminated from the analytic data set.

Acceptability.

This is easy to read, missing data are not common, and there have not been floor or ceiling effects with the diseases studied.

Reliability.
Internal consistency.

For the Skindex-29, the Cronbach's α was 0.87–0.96 for dermatology patients with a mix of inflammatory skin diseases (52%), skin cancers, and benign lesions (95). The Skindex-16 exhibited good internal consistency for each of the scales (Cronbach's α = 0.86, 0.93, and 0.92 for the symptoms, emotions, and functioning scales, respectively) in patients with adult DM (101).

Test–retest reliability.

Skindex scale scores were reproducible after 72 hours (r = 0.88–0.92) when tested in a subset of dermatology outpatients (95). The Skindex-16 shows similar reliability in patients with DM and amyopathic DM (101).

Interrater reliability.

This has not been evaluated for patients with DM.

Validity.
Content validity.

The initial Skindex-61 items and scales were generated from literature review and focus sessions with dermatology patients, physicians, and nurses. The Skindex-29 items and scales were derived from the Skindex-61 by means of psychometric analysis (95). Three additional items related to photosensitivity and alopecia were added to the Skindex-29. Content validity has not been formally assessed for DM.

Criterion validity.

In a study of a variety of dermatology patients, this scale differentiated between skin diseases presumed to have high impact and skin diseases presumed to have a low impact (95). When the Skindex-29 subscores were used to compare adult DM with other dermatologic diseases, DM had among the highest mean subscores, with the emotional subscore being among the most severely affected in patients with DM. DM also showed a higher mean symptom subscore than most compared groups and had a significantly higher score compared to patients with other inflammatory skin conditions, as well as those with normal skin.

Concurrent validity.

Evidence of convergent validity is provided by the pattern of correlation between the Skindex and Short Form 36 (SF-36) comparative scales. For each comparative scale, patients in tertiles classified by low, medium, or high responses to Skindex differed according to scores in the corresponding SF-36 comparative scales (96). In adult DM, the emotional subscale of the Skindex correlated moderately well with 3 emotional subscales of the SF-36.

Construct validity.

Skindex scores correlated more highly than SF-36 scores with patients' self-reports of the condition of their skin and their perceived disfigurement from their skin disease (96). Each of the Skindex-29 subscores significantly correlated with the Dermatology Life Quality Index scores (Skindex-29 symptom r = 0.63–0.86) (101). Skindex subscores correlated mildly to moderately with Cutaneous Dermatomyositis Disease Area and Severity Index scores (r = 0.32–0.46) in adult DM and amyopathic DM patients. A global pruritus visual analog scale (VAS) correlated moderately with Skindex symptoms and function (Spearman's r = 0.46–0.60) and poorly with Skindex emotion (Spearman's r = 0.19). In evaluation of QOL relative to the Dermatomyositis Skin Severity Index, the correlation was moderate (Spearman's r = 0.41) in adult DM and amyopathic DM patients (92). Pruritus VAS correlated moderately (Spearman's r = 0.60) in patients with adult DM (101). Three emotional subscores of the SF-36 moderately correlated with the emotional subscore of the Skindex. As expected, the Health Assessment Questionnaire, a measure of general physical disability, does not correlate well with the emotional scale of the Skindex.

Responsiveness to change.

Mean scale scores remained stable or changed appropriately in patients with a variety of dermatologic conditions over a 3-month period (97). Responsiveness is not available for patients with DM.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The Skindex-29 captures skin-specific QOL issues and corresponds to the severity of skin disease in DM, as well as other skin diseases. A general QOL measure like the SF-36 correlates more highly with increasing degrees of comorbidity and worse self-reported health status, but focuses on functional limitations and emotional state regardless of cause. The Skindex correlates more highly than the SF-36 scores with patients' reports of the condition of their skin. The Skindex is particularly good for evaluating the emotional component of QOL relative to some other measures available. The Skindex (−16 and −29) has internal consistency, test–retest reliability data, and moderate construct validity in patients with adult DM and amyopathic DM.

Caveats and cautions.

This questionnaire is longer than some other skin-specific QOL measures. The meaning of the composite score is less clear than the subscale scores, and scores for subscales are used most frequently. Several items show item bias across sex, age, disease severity, and diagnosis (99). The tool to date has no data on responsiveness, and has not been studied in other myositis subgroups.

Clinical usability.

Based on available psychometric data, the Skindex should be a useful measure in the clinical context. It has been used in many different skin diseases and has been carefully validated, but validity in myositis is limited.

Research usability.

The Skindex has been useful in research assessments of skin diseases, including in 1 study of patients with DM. Further studies of the validity in patients with myositis are needed.

DERMATOLOGY LIFE QUALITY INDEX (DLQI)

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES

Description

Purpose.

The DLQI, developed in 1994, was the first dermatology-specific quality of life (QOL) instrument (102). It is a simple, compact, and practical questionnaire for use in dermatology clinical settings to assess QOL in skin disease. Although the DLQI covers a wide range of life impairments, it is not a multiple-scale questionnaire; its scoring system is restricted to an overall score. There are 2 versions of the DLQI for adults and 2 versions for children: a text-only version and an illustrated version. The illustrated version of the DLQI has been shown to correlate with the text-only version (103). The text version has been used in numerous studies, including the assessment of cutaneous disease as part of other autoimmune diseases, as well as in the evaluation of inflammatory and noninflammatory skin conditions (102, 104–106) There is a children's version of the DLQI, the Children's DLQI, with a text and cartoon version, the latter of which is preferred by children (107, 108).

Content.

The measure consists of 10 questions encompassing skin symptoms and feelings, daily activities, leisure, work or school, personal relationships, and the side effects of treatment.

Number of items and subscales.

10 items, no subscales.

Response options/scale.

Each item is scored on a Likert scale, where 0 = not at all/not relevant, 1 = a little, 2 = a lot, and 3 = very much.

Recall period for items.

1 week.

Endorsements.

None.

Practical Application

How to obtain.

The DLQI has been published (102, 103); the developer was Dr. Andrew Y. Finlay, Department of Dermatology, Cardiff University School of Medicine, Wales, UK (e-mail: FinlayAY@cf.ac.uk). The DLQI may be used by any clinician worldwide for routine clinical practice without seeking permission and without charge. For details of other uses of the DLQI, including research studies, see http://www.dermatology.org.uk/quality/quality-life.html.

Method of administration.

Self-administered questionnaire. The cartoon version has been used for children as young as age 4 years. Parents may complete a parent version of the questionnaire.

Scoring.

Scores of individual items (0–3) are added to yield a total score (0–30); higher scores mean greater impairment of patients' QOL as impacted by their skin disease.

Score interpretation.

Cut points have been determined for scores, corresponding to 0 (score of 0–1, no effect), 1 (score of 2–5, small effect), 2 (score of 6–10, moderate effect), 3 (score of 11–20, very large effect), and 4 (score of 21–30, extremely large effect) in a questionnaire study involving a number of different inflammatory, malignant, and other skin conditions (107).

Respondent burden.

Time for answering the questionnaire is an average of ∼2 minutes.

Administrative burden.

Scoring takes <1 minute. No training is needed for scoring.

Translations/adaptations.

The DLQI is available in 55 languages (104). The DLQI has been studied in the diseases mentioned in the descriptive section above. To date, it has undergone limited study in adults with amyopathic and classic dermatomyositis (DM), but not in other myositis subgroups.

Psychometric Information

Method of development.

Initially, 120 patients generated a list of the ways in which their lives were affected by their skin diseases. This led to identification of 49 aspects of QOL impairments, generating a 10-item questionnaire that was subsequently modified slightly, followed by pilot testing in additional patients (102, 104). This instrument was developed in the UK with patients visiting a university clinic; it focused on patients' ability to function in their daily activities and does not fully capture emotions and mental health (97).

Acceptability.

The DLQI is very readable and easy to complete. Missing data are uncommon. Floor effects have been seen with certain items related to everyday activities and the work/study dimension (109). There are also substantial ceiling effects, with 2 items contributing to most of the variability of the DLQI (109–111).

Reliability.
Internal consistency.

Cronbach's α for the DLQI was assessed in patients with a variety of skin conditions, and ranged from 0.75–0.92 (104). This has not been assessed in DM.

Test–retest reliability.

Test–retest reliability of the DLQI has ranged from 0.56–0.99 in patients with a variety of skin conditions. Most studies showed values >0.90 (104). This has not been assessed in DM.

Validity.
Content validity.

Content validity was established by examining the ability of the instrument to discriminate between patients with skin disease and normal healthy subjects (P < 0.001) (109). There is a question of content related to emotion in adult DM, where the emotional component of QOL is extremely important. Specifically, the correlation between DLQI and Skindex-29 function scores were significantly higher than the correlation between DLQI and Skindex-29 emotion scores in adult DM patients (P = 0.004).

Construct validity.

The DLQI has been used in many studies that have shown significant correlation between the DLQI and generic, dermatology-specific, and disease-specific measures (104). There is low to moderate correlation (Spearman's r = 0.36–0.38) of the DLQI with the Dermatomyositis Skin Severity Index in DM and amyopathic DM patients (92). There is moderate to excellent correlation of the DLQI with Skindex-29 subscores (Pearson's r = 0.63–0.86) in DM and amyopathic DM patients (111). The DLQI exhibited significant but poor correlation with the Cutaneous Dermatomyositis Disease Area and Severity Index (Pearson's r = 0.35) and with a global pruritus visual analog scale (VAS; Pearson's r = 0.27). However, in a second study of adult DM patients, there was moderate correlation of the DLQI with a global pruritus VAS (Spearman's r = 0.58) (101).

Correlations between the DLQI and other dermatology-specific health-related QOL measures were high (r = 0.6–0.86), were moderate for general health-related QOL measures (r = 0.3–0.62), and were in the expected directions except that the DLQI correlates less with mental and emotional aspects (97, 105). Concurrent correlation with the Short Form 36 was demonstrated in an acne study (r = −0.44 to −0.33) (104). In adult DM patients, the DLQI correlated better with the Skindex function subscale (r = 0.86) relative to the Skindex symptoms subscale (r = 0.63) or emotion subscale (r = 0.67).

Criterion validity.

The cut points of the DLQI using global questions show a κ of 0.489 (112). This has not been assessed in DM.

Responsiveness to change.

The ability to detect small impairments may be difficult because of substantial ceiling effects (109–111). However, many studies have demonstrated responsiveness to change (104). The minimum clinically important difference of the DLQI in specific skin diseases has been estimated to range from 2.2–6.9, based on data from 5 studies in other skin diseases (104). Information on the responsiveness and minimum clinically important difference does not exist for DM.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The DLQI focuses on the impact of skin diseas on patients' ability to function in their daily activities and might not fully capture emotions and mental health (106, 111). The strength of the DLQI is its simplicity and broad use for clinical investigation in dermatology, with application to a number of skin conditions (104, 105). The DLQI has limited moderate construct validity in adult DM and amyopathic DM.

Caveats and cautions.

There has been concern that emotions and mental health can be very important in inflammatory skin diseases such as DM. One study found that in DM the correlations between DLQI and Skindex-29 function scores were significantly higher than the correlation between DLQI and Skindex-29 emotion scores (P = 0.004), suggesting that the DLQI might not capture the full range of emotional QOL. There are several limitations related to the focus on disability, response distribution, and dimensionality and item bias. To date, there are no studies of its reliability or responsiveness in adult DM, and no studies in other subgroups of myositis.

Clinical usability.

The DLQI has been used in numerous studies and trials of a number of skin conditions, although it is limited in its study in adult DM patients. It is clinically easy to use.

Research usability.

The DLQI has been well evaluated for a variety of skin diseases and works well for research, with the caveat that the emotional aspect of QOL may be captured better with other instruments. It is thought to be unidimensional, with scoring restricted to an overall score. Validation data in adult DM are limited.

Table  . Summary Table for Measures of Disease Activity in Myositis*
ScalePurpose/contentMethod of administrationRespondent burdenAdministrative burdenScore interpretationReliability evidenceValidity evidenceAbility to detect changeStrengthsCautions
  • *

    N/A = not applicable; VAS = visual analog scale; PM = polymyositis; DM = dermatomyositis; IBM = inclusion body myositis; MMT = manual muscle testing; MRC = Medical Research Council; IIM = idiopathic inflammatory myopathy; HAQ = Health Assessment Questionnaire; C-HAQ = Childhood Health Assessment Questionnaire; CMAS = Childhood Myositis Assessment Scale; MDAAT = Myositis Disease Activity Assessment Tool; MYOACT = Myositis Disease Activity Assessment VAS; MITAX = Myositis Intention to Treat Activities Index; DAS = Disease Activity Score; SF-36 = Short Form 36; HRQOL = health-related quality of life; CHQ = Childhood Health Questionnaire; MDI = Myositis Damage Index; QMT = Quantitative Muscle Testing; ALS = amyotrophic lateral sclerosis; DMD = Duchenne's muscular dystrophy; IBMFRS = Inclusion Body Myositis Functional Rating Scale; SRM = standardized response mean; FI-2 = Myositis Functional Index-2; MAP = Myositis Activities Profile; CDASI = Cutaneous Dermatomyositis Disease Area and Severity Index; CAT = Cutaneous Assessment Tool; DSSI = Dermatomyositis Skin Severity Index; PASI = Psoriasis Area and Severity Index; BSA = body surface area; QOL = quality of life; DLQI = Dermatology Life Quality Index.

Physician global activityOverall rating of myositis disease activity based on all clinical and laboratory measures available at the time of assessmentClinician completedN/A
  • <1 min, but time to assess the patient

  • Hand scored

  • On 10-cm VAS, 0 = inactive disease, 10 = extremely severe disease activity

  • On a Likert scale, 0 = inactive, 1 = mild activity, 2 = moderate activity, 3 = severe activity, 4 = extremely severe activity

Excellent internal consistency and interrater reliabilityExcellent content and construct validityExcellent responsiveness ≥20% improvement is consensus of clinically meaningful change
  • Measures important concept

  • Good psychometric properties

  • Appropriate for clinical and research use

  • Most validated in juvenile PM/DM with some validity in adult PM/DM

  • Somewhat subjective and based on the experience of the rater

  • Reliability of serial ratings dependent on examining previous scores

  • Not validated for IBM

Patient/parent global activityOverall rating of myositis disease activityPatient or parent self-report<1 min
  • <1 min

  • Hand scored

  • On 10-cm VAS, 0 = inactive disease, 10 = extremely severe disease activity

  • On a Likert scale, 0 = inactive, 1 = mild activity, 2 = moderate activity, 3 = severe activity, 4 = extremely severe activity

Ratings distinct from physician ratings. Reliability not available for patient/parent global activityGood construct validityExcellent responsiveness ≥20% improvement is consensus of clinically meaningful change
  • Measures important concept

  • Good psychometric properties

  • Appropriate for clinical and research use

  • Most validated in juvenile PM/DM with some validity in adult PM/DM

  • Somewhat subjective and based on the experience of the rater

  • Reliability of serial ratings dependent on examining previous scores

  • Not validated for IBM

MMTMeasures muscle strength by application of pressure to muscle groups tested against gravity or through a range of motion for muscle groups with less than antigravity strengthAdministered by a trained clinician/ physical therapist
  • Takes 30–60 min to assess 24–26 muscle groups

  • Takes <5 min to assess 8 key muscle groups

  • May be demanding for weak child or younger children with limited ability to cooperate

  • Takes 30–60 min to assess 24–26 muscle groups

  • Takes <5 min to assess 8 key muscle groups

  • Hand scoring <1 min

Modified MRC or Kendall's 0–10 scales used. Scores may be 0–260 for a total score of 12 proximal and distal muscle groups tested bilaterally + 2 axial muscle groups, 0–80 for MMT8Excellent internal consistency, test–retest reliability, very good intrarater reliability. Reliability of scores much better than of individual muscle groups
  • Good content validity for MMT8

  • Good construct validity

  • Excellent responsiveness

  • ≥15% improvement in MMT score in adult PM/DM and ≥18% improvement for juvenile IIM is consensus for clinically important improvement

  • Measures concept central to the assessment of myositis patients

  • Sound psychometric properties

  • Appropriate for clinical and research use

  • Validated in adult and juvenile PM/DM. Does not require special equipment

  • Requires training in administration of the test

  • Widely used but not validated in IBM

  • Total MMT is lengthy for clinical setting

  • Does not distinguish activity from damage Patients with muscle atrophy may not be sensitive to change

HAQ/C-HAQAssesses physical function in 9 (HAQ) or 8 (C-HAQ) domains of daily activitiesSelf- or proxy administeredMinimalMinimalRange 0–3: 0 = no or mild physical dysfunction, <0.125–0.25 = mild physical dysfunction, >1.0 = moderate to severe disability
  • Test–retest reliability excellent in children

  • Internal consistency acceptable for juvenile myositis

  • Intrarater reliability not available in myositis

  • Construct validity excellent in children. Some evidence supportive in adult PM/DM

  • No assessment of content validity in myositis

  • Limited criterion validity in adult PM/DM

  • Responsiveness good to excellent in children with recognized change

  • Data not available for adults

  • Brief and easy to use

  • Takes little time

  • Good psychometrics in children with myositis

  • Significant floor effect

  • Limited validity in adult PM/DM

  • No validity in IBM

CMASAssesses muscle strength, physical function, and enduranceObservational, performance based, administered by clinician or therapist
  • 15–20 min

  • May be demanding for weak child or younger children with limited ability to cooperate

15–20 min to administer, <1 min to score
  • Range 0–52

  • Higher scores indicate greater strength or physical function: <15 = severe weakness (consensus), >48 = normal, >45 = mild impairment, >39 = mild to moderate, >30 = moderate impairment (based on comparison with C-HAQ)

  • Test–retest and interrater reliability very good to excellent

  • Internal consistency not available

  • Strong evidence for construct validity

  • Content validity not assessed

Responsiveness strong in children with recognized change
  • Comprehensive assessment that specifically addresses endurance

  • Reduction in bias and noncompletion due to observational nature

  • Good psychometric properties in juvenile IIM

  • Requires training to administer

  • Time needed to administer may limit usefulness clinically

  • Significant ceiling effect

  • Currently validated only for juvenile IIM and not studied yet in adult myositis subgroups.

MDAATAssesses 6 extramuscular organs to produce a global extramuscular score, and the muscle score, which gives a total disease activity index scoreClinician completedN/A
  • Time to complete a history and physical examination (likely 15–30 min)

  • Hand or computer scored

For MYOACT organ system score scored on 10-cm VAS, 0 = inactive disease, 10 = extremely severe disease activity. For MYOACT each item is answered 0 = not present, 1= improving, 2 = same, 3 = worse, 4 = new, and converted to organ system scores of A–E based on the intent-to-treat. Scores range from 0–60 for the extramuscular MYOACT score and 0–70 for the total MYOACT score, and they range from 0–54 for the extramuscular MITAX score and 0–63 for the total MITAX scoreExcellent internal consistency, good interrater reliability
  • Excellent content validity

  • Good construct validity

  • Excellent responsiveness

  • ≥20% improvement in the extramuscular score is consensus of clinically meaningful change

  • Measures important concept

  • Good psychometric properties

  • Appropriate for clinical and research use

  • Most validated in adult and juvenile DM

  • Somewhat cumbersome to use/score (needs training)

  • MYOACT scores are somewhat subjective and based on the experience of the rater

  • For MYOACT scores, reliability of serial ratings dependent on examining previous scores

  • Not validated for IBM

DASEvaluates muscle and skin involvementClinician completed5 minHand calculated
  • Total score: 0–20, with higher scores meaning higher disease activity

  • Skin subscale 0–9 Weakness subscale 0–11

Good internal consistency, moderate to poor interrater reliabilityGood construct validityExcellent responsiveness
  • Simplicity and good psychometric properties

  • Validation studies in juvenile DM

  • Performance in clinical trials still to be evaluated

  • Not evaluated in other myositis subgroups

SF-36Assessment of the global HRQOL, functional health, and well-beingSelf-administeredMinimal
  • Minimal

  • Scoring is by computer

  • Consists of 36 items answered by marking from 2–6 options

  • Scoring ranges from 0–100, with 0 = maximum disability

Test–retest reliability and intrarater reliability are not available in myositis
  • Good construct and criterion validity in DM and PM, with limited data in IBM

  • Content validity is unavailable in myositis

Statistics on responsiveness not available in myositis
  • Widely used in other diseases

  • Easily administered

  • Available in multiple languages, with extensive normative data

  • Limited experience and validation in adult myositis

  • Costly license

CHQEvaluates physical and psychosocial well-beingParent or child administered10–15 minComputer score with proprietary algorithmSummary score standardNo information available in juvenile DMGood content validity, limited but good construct validityPhysical score moderately responsive
  • Measures important concept

  • Psychometric properties sound

  • Appropriate mainly for research use

  • Respondent burden

  • Complicated computer scoring system

  • Limited studies in juvenile DM

Physician global damageOverall rating of myositis disease damage based on all clinical and laboratory measures available at the time of assessmentClinician completedN/A
  • <1 min, but time to assess the patient

  • Hand scored

  • On 10-cm VAS, 0 = no damage, 10 = extremely severe damage

  • On a Likert scale, 0 = no damage, 1 = mild damage, 2 = moderate damage, 3 = severe damage, 4 = extremely severe damage

Excellent internal consistency and good interrater reliabilityGood content and moderate to excellent construct validityAs expected, little responsiveness in <1 year
  • Measures important concept

  • Good psychometric properties

  • Appropriate for clinical and research use

  • Most validated in juvenile PM/DM with limited validity in adult PM/DM

  • Somewhat subjective and based on the experience of the rater

  • Reliability of serial ratings dependent on examining previous scores

  • Not validated for IBM, and needs additional validation for adult PM/DM

MDIAssessment of damage (persistent or permanent changes) using both VAS and present–absent scoring to assess 9 organ systemsClinician completedN/A
  • Time to complete a history and physical examination (likely 15–30 min)

  • Hand or computer scored

For severity of damage, scores range from 0–110. For each organ system score, scored on 10-cm VAS, 0 = inactive disease, 10 = extremely severe disease activity. For the extent of damage, items are scored present or absent. Total score is 0–35 in children, 0–37 in adolescents, and 0–38 in adults. A higher score indicates more damage
  • Good interrater reliability

  • Severity and extent of damage highly correlate

Good construct and criterion validity
  • Severity of damage score increases slowly in adult PM/DM patients, as expected

  • Extent of damage score shows detectable mild increase

  • Measures important concept

  • Sound psychometric properties

  • Appropriate for research use in adult and juvenile PM/DM

  • Severity of damage scores are somewhat subjective and based on the experience of the rater

  • For severity of damage scores, reliability of serial ratings dependent on examining previous scores

  • Not validated for IBM

QMTMeasures amount of maximum isometric force using specialized equipmentRequires trained health care provider to conduct test1 hour1 hourValues for each muscle group dependent on devices used (kg). Typically measure 8 or 12 muscle groups; total individual score for megascoreGood reliability in ALS trials and DMD; limited but good reliability in adult PM/DMGood but very limited construct validity in IBM
  • Can detect changes in strength, correlated with MMT and IBMFRS

  • SRM not available

  • Quantitative measure

  • Might be sensitive to small changes in strength or in measuring mild weakness

  • Requires specialized training, special hardware and software; costly

  • Patients must have at least antigravity strength to perform

  • Very limited validation in IBM and adult PM/DM

FI-2Assesses dynamic muscle endurance in 7 muscle groupsObservation of functional testN/ATakes maximum of 33 min to assess both right/left sides. Requires maximum of 21 min to assess dominant side. Takes 5 min to score by handEach muscle group is scored as the number of correctly performed repetitions, varying from 0–60 or 0–120. No total scoreInter- and intrarater reliability good to excellent
  • Good content validity

  • Moderate construct validity

Variable; limited data from 1 therapeutic trial
  • Myositis-specific objective functional index that measures muscle endurance and repetition

  • Limited validation studies in adult DM and PM

  • Patients involved in the content validity process

  • Measures an important concept, muscle endurance

  • New instrument requiring a long time to perform

  • Further validation needed for sensitivity to change and in other myositis subgroups

  • A training session is needed to ensure reliability

  • Administrative burden might limit feasibility for use in clinical practice and research

MAP
  • Assesses activity limitation and activities of daily life

  • Contains 31 items divided into subscales

Self-reported questionnaire5–10 min5 min to score by hand
  • Subscales are scored as the median value of item responses within the subscale varying from 1 (no difficulty) to 7 (impossible)

  • Single items are scored as the actual item response, 1–7

  • Moderate test–retest reliability

  • Moderate to strong internal consistency

  • Good content validity

  • Moderate construct validity

Variable; limited data from 1 therapeutic trial
  • Myositis-specific measure of activities of daily living and functional disability

  • Limited validation studies in adult PM/DM

  • Patients involved in content validity process

  • Measures an important concept as to both difficulty and importance of activities

  • Low administrative and patient burden support use in clinical practice and research

  • New measure not yet published in languages other than Swedish.

  • Further validation needed, including sensitivity to change, construct validity, consistency of items, and performance of the tool in other myositis subgroups

IBMFRS10-point disease-specific functional rating scaleInterviewer patient; no special training required15 min15 min10 items, each 0–4 grade; add individual items for total score. 0 = several functional disabilities, 40 = no functional disability or normal functionNot available in myositisModerate construct validityVery responsive in 1 therapeutic trial
  • Measures important elements of daily life functions that are often affected by the disease

  • Quick, inexpensive, and easy to administer

  • IBM-specific measure

  • Responses based on function prior to start of disease; subjective measurements

  • Further validation needed

CDASIMeasures several key features of skin activity and damage in DMClinician completedNoneMean 4.8 minutes for experienced dermatologists, <1 min to hand scoreScores are divided into activity and damage, with scores ranging from 0–100 for activity and 0–32 for damage. Level of disease activity can be interpreted as low, moderate, or high. Mean ± SD CDASI activity for mild disease was 11.4 ± 7.0, moderate was 25.6 ± 8.9, and severe was >39.4Good to excellent inter- and intrarater reliability
  • Content validity adequate by participating dermatologists

  • Moderate to excellent construct validity

Responsiveness strong in a group of patients with recognized change
  • Measures important components of skin activity and damage

  • Psychometric properties sound

  • Appropriate for clinical and research use

  • Partially validated in adult DM, including amyopathic DM

  • Need appropriate training

  • Does not measure every aspect of DM disease, but focuses on elements in the skin likely to be responsive in the context of therapeutic interventions

  • Not validated in other myositis subgroups

CATAssesses skin disease in both activity and damage domainsExamination-based tool, administered by clinician
  • May take up to 15 min, depending on patient complexity and assessor's experience with DM skin disease

  • Abbreviated tool may be faster to complete

May take up to 15 min, but scoring takes <1 min
  • Activity score: range 0–96, ≤1 = no activity, 7 = mild, 13 = moderate, 18 = severe, 31= very severe.

  • Damage score: range 0–20, 0 = no damage, 1 = mild, 2 = moderate, 5 = severe or very severe

  • Total activity score has good internal consistency, test–retest and interrater reliability

  • Total damage score has fair to good internal consistency, test–retest and interrater reliability

  • Reliability of individual activity and damage items are more variable

  • Strong evidence for construct validity in juvenile IIM and more limited in adult DM

  • Content validity not assessed

Responsiveness moderate to strong in children with juvenile DM with recognized change
  • Comprehensive assessment of relevant cutaneous lesions, including both activity and damage

  • Partially validated in juvenile IIM and adult DM

  • Requires training to administer

  • Some concerns about reliability of some items

  • Not validated in other myositis subgroups

DSSIMeasures several key features of skin activity in DMClinician completedNone2–3 min to use by experienced dermatologists, <1 min to score
  • Total DSSI score can range from 0–72

  • Compared to global physician score on a 0–10 VAS, mean ± SD DSSI was 1.28 ± 1.5 for mild global activity, 5.4 ± 4.0 for moderate global activity, and 14.9 ± 14.1 for severe global activity

  • Good intrarater reliability

  • Moderate to good interrater reliability

  • Good to excellent test–retest stability

  • Content validity was evaluated by a panel of experts

  • Moderate but limited construct validity

SRM not available
  • Evaluates elements of skin disease activity of DM

  • Adapted from the PASI for psoriasis

  • Ease of use

  • Evaluated in adult DM and amyopathic DM

  • BSA may not be reliable or responsive to change

  • Does not assess skin damage

  • Not validated in other myositis subgroups

SkindexMeasure of skin-specific QOLPatient self-report 3 subscales: emotions, symptoms, function5 min
  • Scoring involves conversion to linear scale of 100, and then taking the mean of the patient's responses in a given scale

  • Computer scoring

Norms, as well as correlation with QOL burden in a number of different skin diseases, are available. Norms for disease severity are availableExcellent internal consistency and test–retest reliability in other skin diseases and adult DM
  • Moderate construct validity in DM and amyopathic DM

  • Content and criterion validity for other skin diseases, but not available for myositis

Not available for myositis
  • Widely used for autoimmune, inflammatory, and noninflammatory skin diseases

  • Correlates more highly than the SF-36 scores with the patients' reports of the condition of their skin

  • Captures emotional component of QOL well. Limited validity for adult DM and amyopathic DM

  • Longer than some other skin-specific QOL measures

  • No validation in other myositis subgroups

DLQIMeasure of skin-specific QOLPatient self-report2 minScoring takes <1 min
  • Score range 0–30

  • Interpretation can be done by cut points: 0 (score 0–1) = no effect, 1 (score 2–5) = small effect, 2 (score 6–10) = moderate effect, 3 (score 11–20) = very large effect, 4 (score 21–30) = extremely large effect

Not assessed in myositis
  • Moderate to low construct validity in DM and amyopathic DM

  • Content and criterion validity not established in myositis

Not established for myositis
  • Widely used for autoimmune, inflammatory, and noninflammatory skin diseases

  • Short

  • Limited data in adult DM and amyopathic DM

  • Focus on disability, response distribution has ceiling effects, and dimensionality and item bias are problems

  • Not yet studied in other myositis subgroups

REFERENCES

  1. Top of page
  2. INTRODUCTION
  3. PHYSICIAN AND PATIENT/PARENT GLOBAL ACTIVITY
  4. MANUAL MUSCLE TESTING (MMT)
  5. HEALTH ASSESSMENT QUESTIONNAIRE (HAQ)/CHILDHOOD HEALTH ASSESSMENT QUESTIONNAIRE (C-HAQ)
  6. CHILDHOOD MYOSITIS ASSESSMENT SCALE (CMAS)
  7. MYOSITIS DISEASE ACTIVITY ASSESSMENT TOOL (MDAAT)
  8. DISEASE ACTIVITY SCORE (DAS)
  9. SHORT FORM 36 (SF-36)
  10. CHILD HEALTH QUESTIONNAIRE (CHQ)
  11. PHYSICIAN GLOBAL DAMAGE
  12. MYOSITIS DAMAGE INDEX (MDI)
  13. QUANTITATIVE MUSCLE TESTING (QMT)
  14. MYOSITIS FUNCTIONAL INDEX-2 (FI-2)
  15. MYOSITIS ACTIVITIES PROFILE (MAP)
  16. INCLUSION BODY MYOSITIS FUNCTIONAL RATING SCALE (IBMFRS)
  17. CUTANEOUS DERMATOMYOSITIS DISEASE AREA AND SEVERITY INDEX (CDASI)
  18. CUTANEOUS ASSESSMENT TOOL (CAT)
  19. DERMATOMYOSITIS SKIN SEVERITY INDEX (DSSI)
  20. SKINDEX
  21. DERMATOLOGY LIFE QUALITY INDEX (DLQI)
  22. AUTHOR CONTRIBUTIONS
  23. REFERENCES
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