Fibromyalgia: The Fibromyalgia Impact Questionnaire (FIQ)

Authors


FIBROMYALGIA IMPACT QUESTIONNAIRE (FIQ)

General Description

Purpose.

This questionnaire was designed to assess the current health status of patients (predominantly women) with fibromyalgia (FM) (1).

Content.

The FIQ was developed based on information gathered from patient reports, functional status instruments, and clinical observations. The FIQ measures physical functioning, work status (missed days of work and job difficulty), depression, anxiety, morning tiredness, pain, stiffness, fatigue, and well-being over the past week.

Developer/contact information.

Carol S. Burckhardt, PhD, School of Nursing SN-4S, Oregon Health Sciences University, Portland, OR 97201-3098. E-mail: .

Versions.

The original FIQ reported in 1991 contained 10 items (10 subitems in the physical scale) (1). Modifications to the FIQ were made in 1997 (unpublished psychometrics). These modifications included the addition of 1 item to the physical function scale addressing stair climbing, addition of hashmarks to the visual analog scales, and addition of the words “including housework” to the two work-related items. The scoring mechanisms for the 1991 published version and the 1997 modified version differ and are reported in the scoring section.

This instrument has been translated into a number of languages including Korean (2), Swedish (3), Turkish (4), Hebrew (5), and German (6).

Number of items.

1991 version: 10 items (with 10 subitems in physical function). 1997 modified version: 20 items (11 items for physical functioning).

Subscales.

In the 1991 version, the subscales include: physical impairment (10 subitems), feel good (1 item), missed work (1 item) do job (1 item), pain (1 item), fatigue (1 item), rested (1 item), stiffness (1 item), anxiety (1 item), and depression (1 item). The modified version contains the same subscales with the additions and changes noted above.

Populations.

Developmental/target.

Patients with fibromyalgia. In 1991, tested psychometric properties on a sample of 89 women from two clinical sources.

Other uses.

A modified version of the FIQ has been used in patients with post-lyme disease syndrome (7). This version includes 2 new items that assess memory and concentration problems and problems with self-care.

Administration

Method.

Self-administered questionnaire. Easy to complete.

Training.

None required, self-explanatory.

Time to administer/complete.

Approximately 5 minutes.

Equipment needed.

Pen and paper.

Cost/availability.

Original instrument published in 1991 in the Journal of Rheumatology (1). The scoring rubric can be obtained as a.pdf file by contacting Dr. Bennett. Scoring rubric for the modified version can be obtained from Dr. Burckhardt. Modified version available at: http://www.myalgia.com/fiq.pdf.

Scoring

Responses.

Scale.

In the 1991 version, the physical impairment items use a 4-point Likert scale response set ranging from “always” to “never.” The “Feel Good” item response set is the number of days of the week. The “Work Missed” item response is the number of work days per week. The other symptom-based items use 100-mm anchored visual analog scales. In the modified version, the visual analog scales for the symptom-based items are scored in numerical increments from 0 to 10.

Score range.

Final score should range from 0 to 80 (if work-related items are not included). This format is recommended in the scoring rubric by authors.

Interpretation of scores.

Higher scores indicate greater impact of fibromyalgia on functioning.

Method of scoring.

For the 1991 version the final scores for each scale should range from 0 (no impairment) to 10 (maximum impairment).

Physical Impairment: (Questions 1 a–j) Sum all items and divide the sum by the number of questions answered; multiply this value by 3.33. Feel Good: (Question 2): Reverse scoring (so that a higher number indicates impairment). Then multiply new score by 1.43.

Work Missed: (Question 3) Multiply raw score by 2. Do Job: (Question 4) Raw score is final score. Pain: (Question 5) Raw score is final score. Fatigue: (Question 6) Raw score is final score. Rested: (Question 7) Raw score is final score. Stiffness: (Question 8) Raw score is final score. Anxiety: (Question 9) Raw score is final score. Depression: (Question 10) Raw score is final score.

Modified version scoring mechanism: Each scale should range from 0 (no impairment) to 10 (maximum impairment). Physical Impairment: The raw scores for each item range from 0 to 3. Questions 1–11 are scored. Sum all items and divide the sum by the number of questions answered; multiply this value by 3.33. Feel Good: (Question 12) Reverse scoring (so that a higher number indicates impairment). Then multiple new score by 1.43. Work Missed: (Question 13) Multiply raw score by 1.43.

For each symptom-based item (Questions 14–20) the raw score ranges from 0 to 10. If the patient marks between 2 hashmarks the item is given a score that includes 0.5. Do Job: (Question 14) Raw score is final score. Pain: (Question 15) Raw score is final score. Fatigue: (Question 16) Raw score is final score. Rested: (Question 17) Raw score is final score. Stiffness: (Question 18) Raw score is final score. Anxiety: (Question 19) Raw score is final score. Depression: (Question 20) Raw score is final score.

In each instance, the final score is the sum of the scores for the Physical Impairment, Feel Good, Pain, Fatigue, Rested, Stiffness, Anxiety, and Depression scales (does not include 2 work items.)

Time to score.

Brief; varies depending on use of computer to calculate final score.

Training to score.

Minimal.

Training to interpret.

Minimal.

Norms available.

There are no clear norms available. Means and standard deviations for each of the items are presented in Burckhardt et al (1). In the study by Pankoff et al, 28 patients with fibromyalgia (3 male, 25 female), mean age 51.3 years, were recruited from the community (8); the mean total FIQ score was 49.7 (SD 11.4). Goldenberg et al, (9) studied 332 patients with fibromyalgia recruited from a tertiary care center. These subjects were actively seeking employment (mean age 44.3 years, range 22–70) and reported mean total FIQ scores of 54.8 (SD 19.6). Martinez et al (10), in a study of 44 women with fibromyalgia with mean age 43 years and a mean duration of illness of 5.3 years, reported total mean total FIQ score of 47.28 (SD 13.9).Fitzcharles and Esdaile (11) reported mean FIQ scores of 57 (SD = 20.5) in a cross-sectional study of 82 patients with FM (mean age = 48 years, SD =10) recruited from a tertiary center and a community site.

Psychometric Information

Reliability.

Internal consistency.

Not reported in original study. In the study by Hedlin et al (3), a Cronbach's alpha of 0.83 was reported.

Test-retest/stability.

Test-retest correlations using (Pearson's r) ranged from 0.56 (pain) to 0.95 for physical function scale in the original version of the FIQ.

Validity.

Content/domain/face.

Items for the original FIQ were derived from information gathered from patient reports, functional status instruments and clinical observations. On initial testing, a criterion of ≥ 25% impairment on the Arthritis Impact Measurement Scale (AIMS) was used to assess content validity of each item. None of the 4 activity of daily living scale items met the criteria. Opening a jar (dexterity), doing own housework, 2 mobility items and 4 of 5 physical functioning qualified. Thirty-eight percent of the patients did not work so the 2 work items did not apply.

Construct validity.

Principal components analysis identified 5 factors. The first 10 sub-items of the FIQ loaded on physical function (loadings ranged from 0.50 to 0.95). Factor 2 consisted of work difficulty, feeling good, pain fatigue, rest and stiffness. The rest of the items were separate factors.

Concurrent validity.

Correlations with the subscales of the AIMS were as follows: the FIQ physical function correlated 0.65 with the AIMS lower extremity physical function scale. The FIQ pain, depression and anxiety scales correlated strongly with the respective AIMS scales (r = 0.69, 0.73, 0.76). The FIQ item were significantly correlated with AIMS items (range 0.28–0.83). Correlations between the FIQ subscales and the number of tender points ranged from 0.14 (morning tiredness) to 0.74 for work missed.

Responsiveness.

Dunkl et al (12) assessed the responsiveness of the modified FIQ in a sample of 99 patients (8 male, 91 female) with FM recruited from a university-based outpatient clinic, mean age 46.9 years (SD 7.9). The degree of correlation between change in FIQ scores and change in patient's global rating of symptoms was moderate (Spearman r = 0.51).

Comments and Critique

The FIQ appears to be a relatively useful measure of disease impact in patients with fibromyalgia. Difficulties with aggregating data on the psychometric characteristics of this instrument reflect the variable use of scoring mechanisms and versions of the instrument in the research literature. Wolfe et al (13) suggest there is no ideal functional assessment tool for use in this population. Specifically, Wolfe et al state that the FIQ “systematically underestimated impairment by its handling of activities not usually performed,” and express concerns about the non-linearity of the scales. They recommend use of a modified version of the Health assessment Questionnaire for patients with FM. Further examination is needed of the FIQ in clinical trials with specific mention by researchers as to the version used (modified versus original) and scoring rubric implemented.

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