Cross-cultural adaptation and validation of the Brazilian version of the Wisconsin Brief Pain Questionnaire.

CONTEXT

Chronic pain is a common complaint among patients with muscular disease. The Wisconsin Brief Pain Questionnaire (WBPQ) has been used to quantify pain severity and pain interference with daily functions.

OBJECTIVES

To translate the WBPQ for use with Brazilian patients and to evaluate the psychometric properties of the adaptation.

METHODS

We conducted a cross-cultural adaptation of the original English version of the WBPQ for use in Brazil (WBPQ-B) and evaluated the psychometric properties of the adapted version. The original questionnaire was translated, evaluated by an expert panel, pilot tested in 40 patients, and back-translated. Subsequently, the tool was administered, in a cross-sectional study, to 100 adult patients who had muscular disease and were being attended to at our university hospital.

RESULTS

We performed a confirmatory factor analysis and assessed the reliability and validity of the questionnaire (Appendix). The two-factor structure (pain intensity and pain interference) was confirmed satisfactorily. Internal consistency for both scales was adequate (Cronbach's alpha = 0.74 and 0.79, respectively), as was the interrater stability (intraclass correlation coefficients = 0.88 and 0.92, respectively). Convergent validity with the 36-Item Short Form Health Survey was supported by confirmation of a priori hypotheses of negative and satisfactory correlations between the WBPQ-B and some of the 36-Item Short Form Health Survey domains. The pain interference scale correlated higher with the mental summary component. Known-group validity analysis showed that the pain intensity items and scale of the WBPQ-B were higher in the groups where patients with exercise intolerance were concentrated.

CONCLUSION

We found the WBPQ-B to be a reliable and valid instrument for pain assessment of Brazilians who have muscular disease. The survey presents similar psychometric properties to the original version.