Despite its shortcomings, the Fibromyalgia Impact Questionnaire (FIQ) is widely used to assess clinical symptoms and measure therapeutic changes in patients with fibromyalgia (FM). Recently, the revised version of the FIQ (FIQR) was released. In this study, we validated the Korean version of the FIQR and evaluated whether the revised version is superior to the original version in reflecting the physical function and quality of life of these patients.
Seventy-nine patients with FM were invited to complete a questionnaire that included the original FIQ, FIQR, Multidimensional Health Assessment Questionnaire (MDHAQ), Rheumatology Attitudes Index (RAI), and Medical Outcome Study Short-Form 36 (SF-36).
The test-retest reliability was assessed in 55 patients after 1 week, and the Spearman coefficients were 0.604-0.825 and Cronbach's alpha was 0.948 (95% confidence interval 0.930-0.964). The FIQR was significantly correlated with the pain visual analogue scale (VAS), fatigue VAS, RAI, MDHAQ, and physical and mental component summary scores of the SF-36. The FIQR was more strongly associated with the MDHAQ and SF-36 scores than with the original FIQ.
Our study showed that the FIQR is a reliable, valid instrument for assessing patients with FM and performs better in the prediction of physical function and health status than the original version.