The validity and reliability of the Persian version of the Revised Fibromyalgia Impact Questionnaire

The Revised Fibromyalgia Impact Questionnaire (FIQR), an updated version of the Fibromyalgia Impact Questionnaire (FIQ) achieved a better balance among different domains (i.e., function, overall impact, and symptom severity) and attempts to address the limitations of FIQ. As there is no Persian version of the FIQR available, we aimed to investigate the validity and reliability of a Persian translation of the FIQR in Iranian patients. After translating the FIQR into Persian, it was administered to 77 female patients with fibromyalgia syndrome. All of the patients filled out the questionnaire together with a Persian version of the FIQ, short form-12 (SF-12). The tender-point count was also calculated. One week later, FM patients filled out the Persian FIQR at their second visit. Reliability was analyzed by internal consistency and reproducibility including Cronbach’s α coefficient and intra-class correlation coefficient. Construct validity was evaluated by Spearman’s correlation coefficient and Pearson’s correlation coefficient. Statistical analysis was performed using SPSS for Windows version 17.0. All patients included in this study were female, and the mean age was 38.23 ± 10.68 years. The total scores of the FIQR and FIQ were 49.77 ± 18.27 and 54.05 ± 14.00 that were closely correlated (r = 0.63, p < 0.01), and each of the three domains of the Persian FIQR was also correlated well with the three related FIQ domains (r = 0.36–0.63, p < 0.01). Also some significant inverse correlations of FIQR with quality-of-life (assessed by SF-12) domains and items were found. Cronbach’s α was 0.87 for FIQR in the first visit. The Persian FIQR showed adequate reliability and validity. This instrument can be used in the clinical evaluation of Iranian patients with fibromyalgia.