OBJECTIVE: To develop a cross-cultural validation of the Fibromyalgia Impact Questionnaire (FIQ) to the Brazilian population and to analyze its validity and efficacy when applied to fibromyalgia patients. PATIENTS AND METHODS: Forty-four fibromyalgia patients classified following the 1990 American College Rheumatology (ACR) criteria. According to the 1993 Guillemin et al(22) guidelines, four English teachers, one rheumatologist and two physical therapist were invited to participate. The procedure was established according to the following steps: initial translation by two English teachers, evaluation of these two translations to a unique version, back translation to English by two native teachers, a consensus meeting where there were two English teachers, one rheumatologist and physiotherapists for the test-translation, evaluation of cultural equivalency, final version, reliability and reproducibility. The test-translation has been applied to 20 fibromyalgia patients, having in all questions the item "not applicable". Questions answered as "not applicable" by 15% or more patients were reformulated, resulting in the final version. Application of the final version to 24 fibromyalgia patients by two different interviewers who applied the final questionnaire in the same day, with one hour interval and seven days after the first interview, the questionnaire was re-applied by the first interviewer. RESULTS: During the application of the test-version none of the questions were answered as "not applicable" for 15% or more. Consequently, the text was not reformulated. However, there were some difficulty for understanding the visual analogic scales (questions 4 to 10). As a result, "small faces" were added in both ends: a "happy face" to the left and a "sad face" to the right. The evaluation of reliability and reproducibility obtained by the first interviewer (between the first and second application) as well as results obtained by the second interviewer were compared. Both showed no difference among the two interviewers in what concerns the questionnaire application. The p values were above 10% indicating no significant difference between questionnaires application. CONCLUSION: The FIQ Brazilian version, QIF, showed to be a reliable and valid instrument to measure the functional ability and the health state of Brazilian fibromyalgia patients.
fibromyalgia; validation; questionnaire; FIQ
