Fibromyalgia Health Assessment Questionnaire: sensitivity to change

To analyze the responsiveness of the Fibromyalgia Health Assessment Questionnaire (FHAQ) in a group of patients with fibromyalgia (FM).

Observational, prospective and longitudinal study related to the project ICAF was taken part in 15 Spanish centers. 232 patients were included and diagnosed of FM: 98.3% were women, the mean age was 47 years old, they were analyzed at a basal visit and 3 months visit, afterwards an appropriated treatment was prescribed. The statistical analysis was performed including: mean comparison, mean standardized response (RME), basal standard media (DE), intraclass correlation coefficient (R), standard error of the mean (EEM), minimal detectable difference (DMD) and percentage change in real.

The difference in mean comparison of the FHAQ in the baseline visit and the 3 months visit was of 0.098 (95% CI: 0.034–0.16), with a P<.003. Nevertheless the RME was 0.21, a slightly change, the DE=0.57, R=0.81, EEM=0.25, and the DMD=0.69. The percentage change in real was 17% (39 patients). But the sense of the change was positive in 28 cases (less punctuation in the 3 months visit) and negative in other 11 cases (higher punctuation in the 3 months visit).

The punctuation in the 3 months visit was significant better than the basal, but the results of this study do not let it to consider that the FHAQ have enough change susceptibility to recommend it in longitudinal studies. The well knowing fact, some patients can become worse with the treatment prescribed would be to the detriment of the FHAQ psychometric value.