Detailled Information

Burckhardt CS, Clark SR, Bennett RM. The fibromyalgia impact questionnaire: development and validation. J Rheumatol, 1991 May;18(5):728-33.

A review of the FIQ from 1991 to 2005

Validation of an Italian version of the Fibromyalgia Impact Questionnaire (FIQ-I)

Validation of a Persian version of the Fibromyalgia Impact Questionnaire (FIQ-P).

Assessing functional disability and health status of women with fibromyalgia: validation of a Hebrew version of the Fibromyalgia Impact Questionnaire.

It tests the ability to perform large muscle tasks, work difficulty, pain, fatigue, morning tiredness, stiffness, anxiety and depression.

Score Interpretation:

The FIQ is scored in such a way that a higher score indicates a greater impact of the syndrome on the person. Each of the 10 items has a maximum possible score of 10. Thus the maximum possible score is 100. The average fibromyalgia patient scores about 50; severely afflicted patients are usually 70 plus.

The questionnaire is scored in the following manner:

1. The first item consists of 11 questions that make up a physical function scale. The 11 questions are scored and added to yield one physical impairment score. Each item is rated on a 4 point Likert type scale. Raw scores on each item can range from 0 (always) to 3 (never) – thus  the highest total possible raw scores 33. Because some patients may not perform some of the tasks listed, they are given the option of deleting items from scoring. In order to obtain a valid summed score for questions 1 through 11, the scores for the items that the patient has rated are summed and divided by the number of items rated (e.g. if the patient completed only 9 items at a score of 2 for each, the final score would be 9x2/9 =2). An average raw score between 0 and 3 is obtained in this manner.

2. Item 2 is scored inversely, so that a higher number indicates impairment (i.e., 0=7, 1=6, 2=5, 3=4, 4=3, 5=2, 6=1 and 7=0, etc.). Raw scores can range from 0 to 7.

3. Item 3 is scored directly (i.e. 7=7 and 0=0). Raw scores can range from 0 to7.

4. Items 4 through 10 are scored in 10 increments. Raw scores can range from 0 to 10. If the patient marks the space between two vertical lines on any item, that item is given a score that includes 0.5.

5. Once the initial scoring has been completed, the resulting scores are subjected to a normalization procedure so that all scores are expressed in similar units. The range of normalized scores is 0 to 10, with 0 indicating no impairment and 10 indicating maximum impairment.

In order to maintain a maximum possible score of 100 it is necessary to employ an "equalization calculation" if a  patient does not answer all 10 items. If one or more items are missed, the final summative score needs to by multiplied by 10/x. (e.g. if one question is missed multiply by 10/9 [i.e. 1.111], if 2 questions are missed multiply by 10/8 [i.e. 1.25, etc.] )

Problems with the FIQ

The FIQ was developed originally from a fibromyalgia clinic population that was predominantly female. Thus it may have a gender bias, particularly in item 1, in which 4 out of the 11 sub-items are often considered to be more likely to be performed by women, besides one study that report on the physical functioning subscale of the FIQ (i.e. item 1) between men and women and found no difference (6.8 ± 1.9 and 5.5 ± 2.7).

Wolfe et al. performed a Rasch analysis on more than 2500 patients from 4 sites (3 US, 1 Israel) who had completed the FIQ, the SF 36 and 4 versions of the HAQ. In scoring the FIQ, items are either rated on a Likert scaling or on a 0-10 VAS, thus all items have the same weight in the final scoring.

The FIQ tends to underestimate function impairment by its use of activities not usually performed.