To validate a translated and adapted version of the Fibromyalgia Impact Questionnaire (FIQ) for use in French-speaking populations.
The FIQ was translated into French by 2 independent translators and then back-translated into English to assess the conceptual equivalence. The translated version was tested and adapted by an expert committee to obtain the Questionnaire de mesure d'Impact de la Fibromyalgie (QIF), the French version of the FIQ. We administered the QIF to 102 women with fibromyalgia (FM): 71 women who consulted once, and 31 women who were follow for 3 visits (D0, M1, and M3). The patients were also asked to answer 4 other questionnaires: the McGill Pain Questionnaire, the Medical Outcome Study Short Form-36 (SF-36), the short form of the Arthritis Impact Measurement Scale 2 (AIMS2), and the General Health Questionnaire (GHQ) (for psychiatric assessment). To ensure test-retest reliability, the patients were asked to complete the QIF 7 days after the first visit and to send it back to the investigators by mail. During each visit, all patients were asked about pain intensity. A tender point count was obtained by thumb palpation and the tenderness threshold of each specific point was assessed by a 4-point scale score to determine the global tender point index.
No major cultural adaptation was needed to obtain the French version of the FIQ. Test-retest reliability coefficients (intraclass correlation coefficient) for each question ranged from 0.04 to 0.84. Two items from the QIF (number of days when the patient felt good and visual analog scale stiffness) did not reach significant levels of test-retest reliability. Internal validity was good. The QIF score correlated well with the SF-36 and AIMS2 scores. The psychological aspects of the QIF were well correlated with those of GHQ-28. None of the items from the McGill Pain Questionnaire was correlated with QIF items. Similarly the clinical data concerning pain assessment were not correlated with QIF items.
QIF is a valid instrument for measuring functional disability and health status in French women with FM. Some of the items were of a limited reliability, perhaps due to the variability of the multiple aspects of this syndrome.