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INTRODUCTION

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Outcome measurement in spondylarthritis, particularly ankylosing spondylitis (AS) has been a rapidly growing field over the last decade, with enormous progress being made in patient-reported outcomes, clinical assessments, physical measurements and composite scoring of disease state, and response to treatment. Many of these advances arose out of need, when anti–tumor necrosis factor therapies were found to have a role in the treatment of AS patients and therefore required appropriate clinical assessment. The Assessment of SpondyloArthritis international Society (ASAS) was first formed in 1995 as a group of clinicians and methodologists with a shared interest in outcome measurement in AS patients, and has grown to incorporate early diagnosis, classification, development and validation of outcome measures, and evaluation of therapeutic modalities.

The instruments reviewed here include those recommended in the ASAS core sets for clinical record keeping (in daily clinical practice) and for clinical research, as over time these have been extensively validated and implemented across different clinical settings. The core sets describe those health-related domains that “should” be measured in AS patients in different settings, and recommend appropriate instruments that can be used for that domain. Additional measures included are the AS Quality of Life scale and the Health Assessment Questionnaire for the Spondylarthropathies, which cover health domains not included in the original core sets but have been shown to be important to AS patients through the World Health Organization International Classification of Functioning, Disability and Health projects (1). Finally, the AS Disease Activity Score has also been presented, as an alternative to the Bath Ankylosing Spondylitis Disease Activity Index, as one of the newest measures constructed to assess disease activity.

ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To measure disease activity in ankylosing spondylitis (AS) based on a composite score of domains relevant to patients and clinicians, including both self-reported items and objective measures. The ASDAS was first published in 4 draft forms in 2008 (2), and 2 final working versions for use in patients with AS were selected by the Assessment of SpondyloArthritis international Society (ASAS) membership (2, 3).

Content.

The score includes patient-reported assessments of back pain, duration of morning stiffness, peripheral joint pain and/or swelling, general well-being, and a serologic marker of inflammation (erythrocyte sedimentation rate [ESR] or C-reactive protein [CRP]). The ASDAS including CRP has been presented as the preferred version and the one including ESR as the alternative version.

Number of items.

Five items are combined to give a single disease activity score.

Response options/scale.

Continuous scale from zero with no defined upper end.

Endorsements.

The ASDAS has been endorsed by the ASAS and by Outcome Measures in Rheumatology (4).

Examples of use.

The ASDAS has been validated in several observational cohorts and trial populations (5) and is now being used regularly in clinical trials, including longitudinal studies of spondylarthritis patients receiving tumor necrosis factor (TNF) inhibitors (6, 7).

Practical Application

How to obtain.

The ASDAS and aids for its calculation are available online at http://www.asas-group.org.

Method of administration.

Patient response items and a serologic measure of inflammation are mathematically combined to give the ASDAS.

Scoring.

The score is most easily calculated using an online calculator or a hand-held calculator, although it is possible to calculate longhand or using a quick ASDAS calculation form available online.

Score interpretation.

Score ranges from zero (reflecting no disease activity) with the upper end of the scale being determined by the level of the CRP or ESR.

Respondent burden.

The time for the patient to complete the items is very short (estimated at <1 minute) with only 4 single-item questions.

Administrative burden.

Scoring is fast with access to the online calculator, hand-held calculator, or quick assessment forms, but is unwieldy without such a tool.

Translations/adaptations.

The ASDAS has been used in axial spondylarthritis (7) and psoriatic arthritis (8) to date. Since the questions used are taken from the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), there are similar translations available.

Psychometric Information

Method of development.

Items were generated by the 60 ASAS members using a 3-round Delphi process. There were no patients directly involved in item generation. The refined score was then derived using a 3-step statistical approach (principal component analysis, discriminant function analysis, and linear regression analysis) using data from the International Study on Starting TNF Blocking Agents in AS (9). Cross-validation was carried out in the independent Outcome in Ankylosing Spondylitis International Study database.

Acceptability.

The ASDAS is easy to understand, but requires availability of both patient-reported outcomes and serologic values.

Reliability.

Not reported.

Validity.

Regarding content validity, the score items were generated by an international expert group of rheumatologists (ASAS) interested in AS, and the inclusion of serologic markers of inflammation improves the face validity over solely patient-reported domains. Extensive statistical analysis has minimized redundancy between items. Regarding construct validity, Pearson's correlations between the ASDAS-CRP (ASDAS-ESR) and patient global assessment was 0.74 (0.71), and with physician global assessment 0.47 (0.54). The ASDAS shows excellent discrimination between high and low disease activity states as defined by the physician global assessment (standardized mean difference [SMD] at baseline 1.33 for ASDAS-CRP and SMD 1.55 for ASDAS-ESR) based on the Norwegian disease-modifying antirheumatic drug (NOR-DMARD) database (10), and between patients treated with TNF blockers and with placebo (SMD 1.50 for ASDAS-CRP and SMD 1.51 for ASDAS-ESR) based on participants in randomized controlled trials of TNF blockers for AS (3).

Ability to detect change.

The ASDAS was sensitive to improvement with TNF inhibitors in patients with axial spondylarthritis, with an effect size (ES) of 2.04 and a standardized response mean (SRM) of 1.45, and was more responsive than BASDAI (ES 1.86, SRM 1.36) (7). The ASAS group defined 4 important disease states by consensus: inactive disease, moderate, high, and very high disease activity, and relevant cut offs between these states were calculated from the NOR-DMARD database at 1.3, 2.1, and 3.5 units, respectively. Clinically important improvement was found to be 1.1 units or greater and major improvement was defined as a change of 2.0 units or more (11).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The ASDAS is still being validated, but is emerging as the best measure of disease activity in AS on the basis of including both patient-generated items and objective measures of inflammation and on having, to date, equivalent or superior performance when compared to the BASDAI.

Caveats and cautions.

Further validation is required both in AS and in other patient groups to better understand the ASDAS and how it performs as a measure of disease activity, particularly with regard to reproducibility. Although endorsed by ASAS, it is not yet included in any of the ASAS measurement core sets (12, 13).

Clinical usability.

The ASDAS is simple enough to use in the clinical setting, but more evaluation is required as to its psychometric properties.

Research usability.

Initial psychometric evaluation supports the use of the ASDAS in a research setting, without appreciable burden on either respondent or administrator.

ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To measure the impact of ankylosing spondylitis (AS) on health-related quality of life from the patient's perspective. The original instrument was published in 2003 for use in AS patients, and has not been updated (14).

Content.

The questionnaire includes items related to the impact of disease on sleep, mood, motivation, coping, activities of daily living, independence, relationships, and social life.

Number of items.

18.

Response options/scale.

Yes/no responses.

Endorsements.

None.

Examples of use.

The ASQOL is the most frequently used disease-specific measure of health-related quality of life in AS studies. It has recently been used in population studies (15) and to assess the effect of anti–tumor necrosis factor therapy in AS patients (16).

Practical Application

How to obtain.

Available online at http://www.asas-group.org.

Method of administration.

Self-report.

Scoring.

Dichotomous responses, with 0 scored for a “no” and 1 scored for a “yes” for each item. Total score is the sum of the individual responses.

Score interpretation.

Score range is 0–18, with higher scores reflecting greater impairment of health-related quality of life.

Respondent burden.

Between 2 and 16 minutes (median 4 minutes) to complete.

Administrative burden.

Less than a minute to score.

Translations/adaptations.

The original UK English ASQOL continues to be translated and validated in other languages, including US English, Canadian French and English, German, Italian, Spanish, Swedish (17), French (17, 18), Chinese (19), Hungarian (20) and Turkish (17, 21). It has also been validated in patients with axial spondylarthritis (22).

Psychometric Information

Method of development.

Items were generated from patient interviews in the UK and the Netherlands, and scaling properties were tested using Rasch analyses. Conceptually, the ASQOL is based on a needs-based model of health.

Acceptability.

The ASQOL is readable and simple to complete.

Reliability.

Regarding internal consistency, Cronbach's α is reported between 0.89–0.92 in the different study groups (UK, Netherlands, time 1 or time 2). Test–retest reliability was r = 0.91–0.92, and intraclass correlation coefficients were 0.91 (Netherlands) and 0.92 (UK).

Validity.

For content validity, the measure was derived from patient interviews, imparting high relevance to AS patients. Regarding construct validity, the ASQOL correlates moderately well with other AS-specific health outcome measures, including the Nottingham Health Profile components (Spearman's rank correlation coefficient for physical mobility 0.78–0.79, energy 0.73–0.74, pain 0.79–0.81, emotional reactions 0.72–0.73, sleep 0.54 –0.59, and social isolation 0.50–0.53), Bath Ankylosing Spondylitis Functional Index (correlation coefficient 0.72–0.75), Leeds Disability Questionnaire (0.70), Dougados Functional Index (0.80) (14), and the Bath Ankylosing Spondylitis Disease Activity Index (0.79) (23).

Ability to detect change.

The modified standardized response mean measured against AS health transition is reported as −0.35 for improvement and 0.57 for deterioration in health (P < 0.01) and, measured against general health transition, is −0.73 for improvement and 0.48 for deterioration (23). Minimum clinically important difference (MCID) has not been reported for ASQOL, but patient acceptable symptom state has been calculated at 8.0 (24).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The ASQOL is a validated disease-specific health-related quality of life measure for patients with AS, which captures important information on limitation of activities and participation that are not covered in other outcome measures.

Caveats and cautions.

Information on cut offs and MCID is currently lacking.

Clinical usability.

Psychometric evaluation supports the use of the ASQOL in a clinical setting.

Research usability.

Psychometric evaluation supports research use, with minimal administrative or respondent burden.

BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To measure patient-reported disease activity in patients with ankylosing spondylitis (AS). The instrument was first published in 1994 (25) using visual analog scales.

Content.

The index includes patient-reported levels of back pain, fatigue, peripheral joint pain and swelling, localized tenderness, and the duration and severity of morning stiffness.

Number of items.

6 items.

Response options/scale.

Numeric response scale (0–10) or visual analog scale (VAS, 0–10 cm) anchored by adjectival descriptors “none” and “very severe.” Duration of morning stiffness is anchored by a time scale (0–2 or more hours).

Endorsements.

The BASDAI has been endorsed by the Assessment of SpondyloArthritis international Society (ASAS) for the measurement of disease activity (13).

Examples of use.

The BASDAI has been the most frequently used measure of disease activity in clinical trials (26–28) and is recommended to assess response to anti–tumor necrosis factor therapies in AS patients (29, 30). Many regulatory bodies require the BASDAI to be reported for prescribing purposes.

Practical Application

How to obtain.

Available online (in multiple translations) at http://www.asas-group.org.

Method of administration.

Patient self-report questionnaire.

Scoring.

The scores for questions 5 and 6 (severity and duration of morning stiffness) are averaged, the result is then averaged with the remaining 4 question scores to give a final score out of 10.

Score interpretation.

Ranges from 0 (no disease activity) to 10 (maximal disease activity). A cut off of 4 is used to define active disease (29–31). Reference percentile charts have been published (32).

Respondent burden.

Time to complete is between 30 seconds and 2 minutes (mean 67 seconds).

Administrative burden.

Scoring requires less than a minute.

Translations/adaptations.

There are validated translations available in more than 20 languages, including English (25), French (33), Swedish (34), Dutch (35), Turkish (36), German (37, 38), Arabic (39), Spanish (40), and Portuguese (41).

Psychometric Information

Method of development.

Items were generated based on the expert opinion of a group of physiotherapists, researchers, rheumatologists, and patient input.

Acceptability.

The BASDAI is understandable, but missing data have been reported in up to 20% of completions (23). There have been no floor or ceiling effects reported.

Reliability.

Internal consistency is good with a Cronbach's α of 0.84–0.87 (23, 42). Test–retest reliability was good when assessed for inpatients over a 24-hour period (r = 0.93, P < 0.001) (25), and when assessed by postal survey in 162 AS patients who reported no change on an AS-specific health transition question over a 1-week period (intraclass correlation coefficient of 0.87 (95% confidence interval [95% CI] 0.83–0.91) (23).

Validity.

Regarding content validity, the measure was developed by experts in the field with patient input, reflecting items relevant to both patients and clinicians. For construct validity, the BASDAI correlated well with the earlier Bath Disease Activity Index with no significant differences in score distribution, reproducibility, or sensitivity. There is good correlation with the Ankylosing Spondylitis Quality of Life questionnaire (Pearson's correlation coefficient 0.79) and BASDAI is significantly higher in AS patients unable to work due to ill health (P < 0.01) (23). Although largely validated using the VAS, it should be noted that ASAS prefers the use of numeric rating scales (NRS), and there is evidence supporting the replacement of the original VAS answer modalities with NRS (43) in patient self-report instruments in AS.

Ability to detect change.

The modified standardized response mean measured against AS health transition is reported as −0.74 for improvement and 0.60 for deterioration in health (P < 0.01), and measured against general health transition is −1.02 for improvement and 0.74 for deterioration (23). The minimum clinically important difference from the patient's perspective has been reported as 10 mm or 22.5% with a sensitivity of 0.65 and specificity of 0.82, determined using receiver operating characteristic curves analyses (44). A 50% improvement in BASDAI with an intervention (BASDAI50) has been defined as a response to that intervention. Initial evaluation of the patient acceptable symptom state (PASS) in AS patients (45) found the mean change in BASDAI over 12 weeks for the patient to feel well was −3.5 (SD 2.3), and there was significant correlation between the BASDAI 50% responders and patients achieving PASS. Tubach et al described a PASS cut off for BASDAI of 34.5 mm (95% CI 30.9–38.9 mm) (46).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The BASDAI has been the preferred instrument for measuring disease activity in AS patients since its development, and has become the gold standard measure in clinical trials and in daily patient care, specifically in regard to prescribing anti–tumor necrosis factor therapies. It is responsive, easy to administer, and easy to interpret.

Caveats and cautions.

As a patient-generated index, the BASDAI does not include any objective measures that might relate to disease activity, and it does not include the clinician's perspective. Scores are dependent on what the patient perceives as being related to their AS.

Clinical usability.

The BASDAI is easy to use and has found its way into daily clinical practice, although internal consistency (Cronbach's α = 0.87) is a little lower than the 0.90 considered important for an instrument's use in individual patients.

Research usability.

The ease of use, the reproducibility, and the sensitivity to change seen with the BASDAI make it a useful instrument for research purposes.

BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To define and monitor physical functioning in patients with ankylosing spondylitis (AS). The index was developed in 1994 (47) using visual analog scales.

Content.

Eight items concerning activities referring to the functional anatomy of the patients (bending, reaching, changing position, standing, turning, and climbing steps), and 2 items assessing the patients' ability to cope with everyday life.

Number of items.

10 items.

Response options/scale.

Numeric response scale (0–10) or visual analog scale (0–10 cm) anchored by adjectival descriptors “easy” and “impossible.”

Endorsements.

Endorsed by the Assessment of SpondyloArthritis international Society.

Examples of use.

The BASFI is the most widely used functional index for assessment of AS patients, primarily in studies of disease impact (48, 49) and in clinical trials (26, 27).

Practical Application

How to obtain.

Available online at http://www.asas-group.org.

Method of administration.

Patient self-report questionnaire.

Scoring.

The mean of the individual scores is calculated to give the overall index score.

Score interpretation.

Score range is 0–10, with 0 reflecting no functional impairments and 10 reflecting maximal impairment. Reference percentile charts have been published (32).

Respondent burden.

The instrument takes <3 minutes to complete.

Administrative burden.

Scoring is simple and quick.

Translations/adaptations.

The BASFI has been translated and validated in over 18 languages, including English (47), French, German, Dutch, Spanish (40), Portuguese (41), and Chinese (50).

Psychometric Information

Method of development.

Items were generated by an expert group of physiotherapists, researchers, rheumatologists, and patients. No factor analysis or principal component analysis was performed.

Acceptability.

The questions are easy to comprehend. The median score has been reported as 2.0, with clustering at the lower end of the scale (51); studies with item-response theory have indicated that the BASFI is not a linear scale (51, 52).

Reliability.

Internal consistency is excellent, with Cronbach's α reported at 0.936 (53). Test–retest reliability was good when scores were repeated after a 24-hour interval (r = 0.89, P < 0.001) (47), and in patients stable on anti–tumor necrosis factor treatment (r = 0.92, P < 0.0001) (54). Interobserver reliability measured between patient self-report and the score given by a physiotherapist after observing the tasks being performed has also been reported (r = 0.87–0.89, P < 0.001).

Validity.

Regarding content validity, the BASFI was developed by a multidisciplinary group of experts in AS, with input from AS patients. For construct validity, there is good evidence of validity through comparison with instruments that measure similar or related constructs, and with measures of mobility (55). The BASFI is highly correlated with the Dougados Functional Index (Spearman's correlation coefficient 0.89) (35). Correlations are less strong with patient-reported disease activity (r = 0.33) or physician-reported disease activity (r = 0.33) (35).

Ability to detect change.

Responsiveness statistics for the BASFI have been published as an effect size (ES) of 0.36 (moderate) and standardized response mean (SRM) of 0.46 for improvement, and an ES of 0.70 and SRM of 0.72 for deterioration in the setting of a trial of nonsteroidal antiinflammatory drugs. Although responsive in placebo-controlled trials of active drugs (56, 57), the BASFI is less responsive in the setting of physical therapy interventions (58, 59). The minimum clinically important difference from the patient's perspective has been reported as 7 mm or 17.5% with a sensitivity of 0.60 and specificity of 0.85, determined using receiver operating characteristic curves analyses (44). In assessing patient acceptable symptom state (PASS), Dougados et al found the mean change in BASFI over 12 weeks for the patient to feel well was somewhat larger at −2.4 (SD 2.0) (45), with a PASS cut off reported by Tubach et al of 31.4 mm (95% confidence interval 26.9–37.0 mm) (46), and slightly higher by Maksymowych et al using the numeric rating scale of 4.0 cm (24).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The BASFI is a valid measure of physical function in AS patients and has good discrimination between groups and interventions. It is simple and easy to use and score. The tool was designed for use in AS, but can also be used in the other spondylarthritides.

Caveats and cautions.

The BASFI may not be sufficiently sensitive to detect subtle changes in functioning in the relatively well AS patient, or in trials of physical therapies.

Clinical usability.

Psychometric evaluation supports its use in a clinical setting.

Research usability.

Psychometric evaluation supports its use in a research setting, being short, easy to complete, reproducible, and sensitive to change at a group level.

BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To give a global assessment of the well-being of the person with ankylosing spondylitis (AS) over a given time period. It was first introduced by Jones et al in 1996 (60).

Content.

Two visual analog scales to measure the effect of AS on the respondent's well-being, the first estimated over the last week, the second over the last 6 months.

Number of items.

Two items.

Response options/scale.

Scale between 0 (none) to 10 (very severe effect).

Endorsements.

Endorsed by Assessment of SpondyloArthritis international Society (ASAS).

Examples of use.

Relevant references in which instrument has been used.

Practical Application

How to obtain.

Available online at http://www.asas-group.org.

Method of administration.

Patient-completed.

Scoring.

There are no specific scoring instructions.

Score interpretation.

Higher scores reflect a more severe effect of the disease on general well-being.

Respondent burden.

Less than a minute required to complete.

Administrative burden.

Minimal.

Translations/adaptations.

Few published translations have been validated; Dutch and Norwegian translations are available on the ASAS web site.

Psychometric Information

Method of development.

Not reported.

Acceptability.

Very simple to understand and complete.

Reliability.

There is no evidence for internal consistency. Test–retest reliability was good when scores were repeated after a 24-hour interval (r = 0.84 for 1 week, r = 0.93 for 6 months) in the original study of 329 AS patients (60), and in patients stable on anti–tumor necrosis factor treatment over 1 week (r = 0.74, P < 0.0001) (54).

Validity.

Regarding construct validity, the BAS-G correlated better with other patient-reported health measures (r = 0.73 for Bath Ankylosing Spondylitis Disease Activity Index and r = 0.30–0.59 for Bath Ankylosing Spondylitis Functional Index) than it did with objective physical measures (r = −0.16 for Bath Ankylosing Spondylitis Metrology Index).

Ability to detect change.

Satisfactory sensitivity to change was reported, with a mean difference between pre- and postglobal scores of 1.54, SEM 0.31, P = 0.001 (60). The minimal clinically important difference from the patient's perspective has been reported as 15 mm or 27.5% with a sensitivity of 0.61 and specificity of 0.74, determined using receiver operating characteristic curve analyses (44).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The BAS-G is the simplest of the patient-reported outcome measures in AS and a good indicator of the patient's perspective on the overall effect of their health on well-being. It is appropriate for assessing interventions aiming to improve overall disease impact, and likely reflects many constructs that are implicitly relevant for patients including fatigue, emotions, fears and anxiety, side effects of medications, and restrictions in social roles. The BAS-G is easily applied to all spondylarthritis groups.

Caveats and cautions.

Being unidimensional, the BAS-G is entirely reliant on the patient's perception of their disease and how it affects the aspects of their life that are important to them. Patients with similar physical functioning may express the impact of disease differently. The BAS-G has not been as well evaluated as the other Bath AS indices.

Clinical usability.

The BAS-G is simple to use, simple to evaluate, and appropriate for use in the clinical setting.

Research usability.

There is insufficient psychometric evidence to support widespread research use.

BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To quantify the mobility of the axial skeleton in ankylosing spondylitis (AS) patients and allow objective assessment of clinically significant changes in spinal movement. The BASMI was first published in 1994 (61) as a 2-point scale, was adapted a year later into a 10-point scale, and has more recently been proposed and validated as a linear construct (62).

Content.

Clinical measures of cervical rotation, tragus to wall distance, lumbar flexion, lumbar side flexion, and intermalleolar distance.

Number of items.

5 items.

Response options/scale.

Each item is scored from 0–10 based on individually defined cut points. Ranges are given as cervical rotation (>85.0° to ≤8.5°), tragus to wall (<10 cm to ≥38 cm), lumbar flexion (>7.0 cm to ≤0.7 cm), lumbar side flexion (>20.0 cm to <1.2 cm), and intermalleolar distance (≥120 cm to <30 cm).

Endorsements.

Endorsed by the Assessment of SpondyloArthritis international Society (ASAS).

Examples of use.

The BASMI is included in the ASAS core sets as the preferred measure of spinal mobility. It has been used in clinical trials of anti–tumor necrosis factor agents in AS patients (63, 26), and more recently was the outcome measure used to show that spinal mobility is determined by both spinal inflammation and by structural damage (64).

Practical Application

How to obtain.

The BASMI10 is available at http://www.asif.rheumanet.org/basmi-10-e.pdf, and the linear version is available at http://www.asif.rheumanet.org/basmi-lin-e.pdf. Translations into Norwegian, German, and Danish are also available at http://www.asas-group.org and http://www.asif.rheumanet.org/assessment.htm.

Method of administration.

Measurements are performed by health care providers who have been trained to perform the clinical examinations required.

Scoring.

In the original instrument (BASMI2) (61), each continuous assessment was converted into a nominal score of 0, 1, or 2. The next year a second nominal version was published (BASMI10) (65), with individual assessments scored between 0 and 10. More recently a linear version has been proposed (BASMIlin) (62), with scoring ranges similar to the BASMI10.

Score interpretation.

Individual scores are summed for the BASMI2 or averaged for the BASMI10 to give a final score between 0 and 10, where a higher score reflects more significant impairment of spinal mobility. Normative values have been published previously (32) using the BASMI10.

Respondent burden.

The BASMI takes ∼5–10 minutes to complete, depending on the experience of the clinician.

Administrative burden.

Scoring is straightforward and takes less than a minute to complete.

Translations/adaptations.

Multiple languages are available, including English (61, 65), Finnish (66), Portuguese (67), German, Danish, and Norwegian.

Psychometric Information

Method of development.

Measurements were chosen by a group of rheumatologists, physiotherapists, and research associates with a special interest in AS, based on an extensive literature review and clinical experience. The chosen measurements were found to be most reliable and clinically useful to reflect axial “status.”

Acceptability.

The instrument is easily understood and is published with step-by-step instructions as to how one should perform the clinical measures. Most of the measures are easy to carry out, although appropriate measurement of intermalleolar distance can be difficult in a small clinic room. The BASMI2 does not perform as well as the BASMI10 or the BASMIlin, scoring lower at the lower end of the scale and higher at the higher end, with different magnitude of changes at different ends of the scale. The BASMI10 and BASMIlin both behave in a more linear fashion, making them more suitable for monitoring AS patients over time (62).

Reliability.

Interrater reliability has been shown to be good; comparisons between 3 physiotherapists revealed the following: cervical rotation (r = 0.98, P < 0.001), tragus to wall (r = 0.99, P < 0.001), lumbar side flexion (r = 0.94, P < 0.001), lumbar flexion as measured by the modified Schober's method (r = 0.99, P < 0.001), and intermalleolar distance (r = 0.98, P < 0.001). Intraobserver reliability for the same 3 physiotherapists on consecutive days showed similar high values: cervical rotation (r = 0.99, P < 0.001), tragus to wall (r = 0.99, P < 0.001), lumbar side flexion (r = 0.98, P < 0.001), lumbar flexion as measured by the modified Schober's method (r = 0.99, P < 0.001), and intermalleolar distance (r = 0.99, P < 0.001).

Validity.

Content validity is fair, with the initial instrument development based on an extensive literature review and a panel of clinicians and research associates with a special interest in AS. Thoracic spinal mobility is under-represented in this instrument as indicated by the lack of association between the BASMI and thoraco-abdominal motion in AS patients (68), and the ASAS group recommends the addition of chest expansion to the core set for clinical evaluation in AS patients to address this limitation. Regarding construct validity, the BASMI has been shown to discriminate between patients with and without radiographic change due to AS (69). The BASMI does not correlate strongly with changes in functional outcomes as measured by the Bath Ankylosing Spondylitis Functional Index (r = 0.44 for BASMI2, r = 0.46 for BASMI10, P < 0.001) (70). Spinal mobility, as measured by the BASMIlin, correlates with radiographic change as measured by the Stoke Ankylosing Spondylitis Spine Score (Spearman's ρ = 0.6) and less strongly with inflammation as measured on magnetic resonance imaging (ρ = 0.3), with both contributing independently to spinal mobility (64). For criterion validity, the comparison between the 5 BASMI measures and total scores of 20 clinical measurements (total metrology score) was good (r = 0.92, P < 0.001).

Ability to detect change.

Jenkinson et al (61) reported a 30% improvement in BASMI scores over a 3-week period of inpatient treatment in 56 patients. Clinimetric properties of the 3 versions of BASMI were tested in 187 patients from the Outcomes in Ankylosing Spondylitis International Study, giving calculated Guyatt's effect sizes of 0.66 for BASMI2, 0.95 for BASMI10, and 1.04 for the BASMIlin (62).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The BASMI is valid, reproducible, and easy to perform with minimal training, giving valuable information about spinal mobility due to inflammation or structural damage. It is the measure of choice put forward by ASAS to measure spinal mobility in clinical trials. It is an appropriate measure for assessing the effect of interventions in patients with AS and spondylarthritis. On the strength of our current understanding of these measures, both the BASMI10 and the BASMIlin perform well for the assessment of spinal mobility.

Caveats and cautions.

The instrument does not assess thoracic mobility in isolation, and it is recommended that the BASMI be used in conjunction with chest expansion or another measure of thoracic mobility for more accurate assessment of spinal mobility. Many of the earlier published studies that refer to the BASMI do not specify if it is the BASMI2 or the BASMI10 that is being carried out, which may have implications on the interpretation of results.

Clinical usability.

The BASMI10 and BASMIlin are sufficiently sensitive and reliable for use in clinical practice; however, the administrative burden of up to 10 minutes to carry out the physical measures may limit its use in this setting.

Research usability.

The BASMI lends itself well to use in clinical trials, is sensitive enough to detect change between treatment groups, and adds important information not obtained with other outcome measures.

DOUGADOS FUNCTIONAL INDEX (DFI)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To assess the functional abilities of persons with ankylosing spondylitis (AS). The DFI was first published as the Ankylosing Spondylitis Functional Index in 1988 (71). A more recent modification uses a 5-point Likert response scale in place of the original 3-point scale described below.

Content.

Items cover activities of daily living including dressing, bathing, standing, climbing stairs, changing position, bending, doing housework or usual job, coughing or sneezing, and breathing deeply. Each question begins with “Can you … .”

Number of items.

20.

Response options/scale.

The Likert scale is 0 = yes, with no difficulty; 1 = yes, but with difficulty; and 2 = impossible to do. Item scores are added to give a total functional index.

Endorsements.

Endorsed by the Assessment of SpondyloArthritis international Society as an alternative to the Bath Ankylosing Spondylitis Functional Index (BASFI) for measuring the core concept of physical function in AS.

Examples of use.

The DFI continues to be used to measure physical function in studies of disease outcome (72) and to measure change in physical function due to treatment with antiinflammatory drugs in randomized controlled trials (57, 73).

Practical Application

How to obtain.

French, Finnish, and Russian versions are available online at www.asas-group.org.

Method of administration.

Self-report questionnaire.

Scoring.

The individual scores for each item are summed for a final index score.

Score interpretation.

Score ranges from 0–40, with higher values reflecting higher functional impairment (worse physical functioning).

Respondent burden.

Time to complete not given. Considerably longer than the BASFI.

Administrative burden.

Hand-scored, time to score minimal.

Translations/adaptations.

The original French version has been translated into multiple languages including English, German (74), Italian (75), Spanish (40) and Turkish (76). The DFI has been used (but not validated) in other spondylarthritis subgroups including reactive arthritis and psoriatic arthritis patients.

Psychometric Information

Method of development.

Items were generated in an expert group of 3 rheumatologists experienced in the management of patients with AS. Patients were not involved in the development process. Preliminary component analysis was used to refine items.

Acceptability.

The questions are easily understandable. There is clustering at the low (normal) end of the scale, and the response “yes, but with difficulty” covers a very wide range of functional restriction.

Reliability.

Cronbach's alpha was not given. Interrater reliability has been reported as high between 2 independent observers (rheumatologists, not patient-scored) with an intraclass correlation coefficient (ICC) of 0.99. Intrarater reliability of an independent observer scoring the index on 2 occasions 1 week apart gave an ICC of 0.86. Test–retest reliability was good when scores were repeated after a 24-hour interval (r = 0.96, P < 0.001) in inpatients with AS (47).

Validity.

Regarding content validity, the initial item pool was generated by 3 rheumatologists and refined using principal component analysis. Regarding construct validity, the DFI discriminates between AS inpatients and outpatients (47), AS patients with high and low disease activity (77), and AS smokers and nonsmokers (78). The DFI is highly correlated with the BASFI (Spearman's correlation coefficient 0.89) (35), and moderately correlated with the Health Assessment Questionnaire (HAQ) disability index (r = 0.66), the HAQ for the Spondylarthropathies (r = 64), and the Arthritis Impact Measurement Scales 2 (r = 0.55) (79). Correlations are less strong with patient-reported disease activity (r = 0.32), physician-reported disease activity (r = 0.36) (35), or physical limitations (including cervical rotation, r = −0.23; Schober's test, r = −0.13) (79). Criterion validity was assessed using a multiple regression model, including the DFI score, and clinically measured morning stiffness, number of nocturnal awakenings, chest expansion, Schober's test, hand-ground distance, self-physiotherapy, and pain. The correlation coefficient between the independent variables and the functional index (dependent variable) was R2 = 0.41.

Ability to detect change.

Responsiveness statistics for the DFI include an effect size (ES) of 0.30 (moderate) and standardized response mean (SRM) of 0.33 for improvement, and an ES of 0.47 and SRM of 0.59 for deterioration (51).

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The DFI is a valid instrument for measuring physical functioning in AS and is responsive to change. It is most appropriate in patients with predominantly axial involvement.

Caveats and cautions.

The concepts included in the DFI are centered on axial and large joint functioning, which may limit its use in individuals with significant peripheral joint or extraarticular involvement. There is a significant floor effect with clustering of responses toward the lower end of the scale, and the 3-response Likert scale is overly simplistic to capture subtle changes in functioning.

Clinical usability.

There is insufficient evidence to support the use of the DFI for clinical practice. The time required to complete the measure may limit clinical use.

Research usability.

The DFI is an appropriate measure for research use; however, respondent burden may limit its feasibility. Shorter, equally valid instruments (e.g., the BASFI) are likely to be favored in this setting.

HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES

Description

Purpose.

To assess the physical functioning of an individual with ankylosing spondylitis (AS). The HAQ-S was adapted from the original HAQ in 1990, incorporating issues of physical functioning and impairment specific to patients with AS (80).

Content.

The measure includes items concerning dressing, arising, eating, walking, hygiene, reaching, gripping, and errands and chores taken from the disability index (DI) of the HAQ (81), and an additional 5 specific items concerning neck function and static posture (driving a car, using a rear-vision mirror, carrying heavy groceries, sitting for long periods, and working at a desk).

Number of items.

There are 25 items (20 from the HAQ-DI and 5 unique to the HAQ-S).

Response options/scale.

Responses are 0 = able to do with no difficulty; 1 = able to do with some difficulty; 2 = able to do with much difficulty; and 3 = unable to do. The final score range is 0–3.

Endorsements.

No formal endorsements.

Practical Application

How to obtain.

The original, more generic HAQ and its shorter form, the HAQ-DI, are available at http://aramis.stanford.edu/HAQ.html. The 5 extra questions are outlined in the original HAQ-S manuscript (80).

Method of administration.

Self-report questionnaire.

Scoring.

The responses are hand-scored, and the 10 individual subscale scores are averaged to give a summary HAQ-S score.

Score interpretation.

The range of the final calculated summary score is 0–3, where a higher score indicates higher impairment or worse function.

Respondent burden.

Time to complete is not given. Normative values are available for the original HAQ-DI (82), but not for the spondylarthritis-specific instrument.

Administrative burden.

Minimal time is required for scoring.

Translations/adaptations.

Multiple translations of the original English version are available, including Dutch (83, 84), Finnish (85), Spanish (86), Brazilian-Portuguese (87), and Turkish (88). The HAQ-S has also been used to assess functioning in patients with psoriatic arthritis (7).

Psychometric Information

Method of development.

The existing HAQ-DI was adapted for use in spondylarthritis patients by adding 5 disease-specific items, determined by the investigators (methods not given).

Acceptability.

The instrument is readable and understandable. There is a floor effect with score clustering at the normal (0) end of the scale described.

Reliability.

Test–retest showed stability between time 1 and time 3, with Pearson's correlation coefficient given as r = 0.92.

Validity.

For content validity, the original HAQ was felt to show good face validity related to the difficulties with activities of daily living reported by a group of 300 British AS patients (80, 89). Additional spondylitis-specific items were developed by the investigators. Regarding construct validity, the HAQ-S is highly correlated with the original HAQ-DI (Spearman's correlation coefficient 0.96), and moderately correlated with other measures of physical functioning, the Dougados Functional Index (r = 0.64) and the generic instrument, Arthritis Impact Measurement Scales (r = 0.80) (79). For criterion validity, correlations are less strong with physical limitations (including cervical rotation, r = −0.50; Schober's test, r = −0.36) (79).

Ability to detect change.

Responsiveness statistics for the HAQ-S show an effect size (ES) of 0.20 (moderate) and standardized response mean (SRM) of 0.28 for improvement, and an ES of 0.28 and SRM of 0.72 for deterioration (51) in a cohort of AS patients treated with nonsteroidal antiinflammatory drugs.

Critical Appraisal of Overall Value to the Rheumatology Community

Strengths.

The instrument measures aspects of physical function and impairments in activities of daily living in patients with AS. It is sensitive in early disease as well as in advanced disease. It can be applied to all the spondylarthritides (not only AS patients).

Caveats and cautions.

The HAQ-S is longer than other disease-specific measures of physical functioning and does not perform a great deal better than the alternatives. Information relating to minimum clinically important difference, relevant cut offs and patient acceptable symptom state is lacking.

Clinical usability.

There is insufficient evidence to support the use of the HAQ-S in individual patient care. Respondent burden may also limit clinical use.

Research usability.

There is good evidence to support the use of the HAQ-S for research use, as a valid easily administered tool to measure physical function.

Table  . Summary Table for Ankylosing Spondylitis Measures*
ScalePurpose/contentMethod of administrationRespondent burdenAdministrative burdenScore interpretationReliability evidenceValidity evidenceAbility to detect changeStrengthsCautions
  • *

    ASDAS = Ankylosing Spondylitis Disease Activity Score; ES = effect size; SRM = standardized response mean; TNF = tumor necrosis factor; BASDAI = Bath Ankylosing Spondylitis Disease Activity Index; ASQOL = Ankylosing Spondylitis Quality of Life scale; MCID = minimum clinically important difference; PASS = patient acceptable symptom state; BASFI = Bath Ankylosing Spondylitis Functional Index; AS = ankylosing spondylitis; BAS-G = Bath Ankylosing Spondylitis Global Score; BASMI = Bath Ankylosing Spondylitis Metrology Index; DFI = Dougados Functional Index; HAQ-S = Health Assessment Questionnaire for the Spondylarthropathies.

ASDASMeasures disease activitySelf-report<2 minutesHand/computer scoreScore from 0 (no disease activity), higher values reflecting higher disease activityNot reportedContent, construct validityES 2.04, SRM 1.45 for improvement with anti-TNF therapy Clinically important improvement 1.1 units, major improvement 2.0 unitsMeasures important concept with stronger content validity than the BASDAI, extensive validity evidence Appropriate for research useStill being validated Reliability evidence not reported Use in a clinical setting requiring further assessment
ASQOLMeasures quality of lifeSelf-reportMedian 4 minutes (range 2–16 minutes)Hand score0–18, higher scores reflecting greater impairment of quality of lifeInternal consistency, test–retest stabilityContent, construct validity
  • mSRM 0.35 (improvement)

  • mSRM 0.57 (deterioration)

Measures important concept, psychometric properties sound, appropriate for clinical and research useInformation on MCID and PASS is lacking
BASDAIMeasures disease activitySelf-reportMean 67 seconds (range 30 seconds–2 minutes)Hand score0 (none or no symptoms) to 10 (very severe symptoms)Internal consistency, test–retest stabilityContent, construct validity
  • mSRM 0.74 (improvement)

  • mSRM 0.60 (deterioration)

  • ES 1.86, SRM 1.36 for improvement with anti-TNF therapy

  • MCID 10 mm (22.5%)

  • PASS cut off 34.5 mm

Measures important concept, psychometric properties sound, appropriate for clinical and research useScore based solely on patient-report may omit important objective elements of disease activity
BASFIMeasures functional statusSelf-report<3 minutesHand score0 (no functional impairments) to 10 (maximal impairment)Internal consistency, test–retest stability, interrater reliabilityContent, construct, and criterion validity
  • ES 0.36, SRM 0.46 (improvement)

  • ES 0.70, SRM 0.72 (deterioration)

  • MCID 7 mm (17.5 %)

Measures important concept, psychometric properties sound, appropriate for clinical and research useLess sensitive in the well AS patient
BAS-GEffect of AS on well-beingSelf-report<1 minuteHand score0 (no effect on well-being) to 10 (very severe effect on well-being)Test–retest stabilityConstruct validityMCID 15 mm (27.5%)Measures important concept, psychometric properties sound, appropriate for use in a clinical settingLess well evaluated than other scales
BASMISpinal mobilityPhysical measures5–10 minutesHand score0 (normal spinal mobility) to 10 (severely restricted spinal mobility)Interrater reliability, Intrarater reliability, test–retest stabilityContent, construct, and criterion validity
  • ES 0.66 (BASMI2)

  • ES 0.95 (BASMI10)

  • ES 1.04 (BASMIlin)

Measures important concept, appropriate for use in a research settingLimited by the lack of thoracic spine measures
DFIMeasures functional statusSelf-reportNot statedHand score0–40, higher values reflecting higher functional impairmentInterrater reliability, Intrarater reliability, test–retest stabilityContent, construct, and criterion validity
  • ES 0.30, SRM 0.33 (improvement)

  • ES 0.47, SRM 0.59 (deterioration)

Measures important concept, psychometric properties sound, appropriate for research use5-point Likert scale likely better than original 3-point, but less well validated Information on use in clinical care is lacking
HAQ-SMeasures functional statusSelf-reportNot statedHand score0–3, higher values reflect higher impairmentTest–retest stabilityContent, construct, and criterion validity
  • ES 0.20, SRM 0.28 (improvement)

  • ES 0.28, SRM 0.72 (deterioration)

Measures important concept, psychometric properties sound, appropriate for research useInformation on MCID, PASS, and use in clinical care is lacking

REFERENCES

  1. Top of page
  2. INTRODUCTION
  3. ANKYLOSING SPONDYLITIS DISEASE ACTIVITY SCORE (ASDAS)
  4. ANKYLOSING SPONDYLITIS QUALITY OF LIFE SCALE (ASQOL)
  5. BATH ANKYLOSING SPONDYLITIS DISEASE ACTIVITY INDEX (BASDAI)
  6. BATH ANKYLOSING SPONDYLITIS FUNCTIONAL INDEX (BASFI)
  7. BATH ANKYLOSING SPONDYLITIS GLOBAL SCORE (BAS-G)
  8. BATH ANKYLOSING SPONDYLITIS METROLOGY INDEX (BASMI)
  9. DOUGADOS FUNCTIONAL INDEX (DFI)
  10. HEALTH ASSESSMENT QUESTIONNAIRE FOR THE SPONDYLARTHROPATHIES (HAQ-S)
  11. AUTHOR CONTRIBUTIONS
  12. REFERENCES
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