[Cultural adaptation and validation of the "Fibromyalgia Impact Questionnaire"--Portuguese version]

The aim of this study was to translate the Fibromyalgia Impact Questionnaire (FIQ) into Portuguese (Portugal) and to evaluate its reliability and validity by use with Portuguese--speaking patients with Fibromyalgia. After translating the FIQ into Portuguese we administered it to 68 patients with Fibromyalgia together with an informed consent, a Portuguese version of the Health Assessment Questionnaire (HAQ) and a formulary with the socio-demographic characteristics and duration of the complaints. The content validity was assessed with a panel of experts, with high consensus. In the concurrent validity, we obtained significant correlations between the FIQ first item and the HAQ [r = 0,531 (p = 0,001)]. Cronbach's alpha was 0,814, indicating an acceptable level of internal consistency. In conclusion, the Portuguese version of the FIQ is a reliable and valid instrument for measuring health status and physical functioning in Portuguese patients with Fibromyalgia. This instrument is available for use in the clinical practice.