The Modified Back Beliefs Questionnaire as a tool to screen for incorrect beliefs regarding back pain: Cross-cultural adaptation and measurement properties

Abstract

BackgroundThe Modified Back Beliefs Questionnaire (MBBQ) evaluates and screens for incorrect beliefs about low back pain (LBP). Although the MBBQ has been used to assess, its measurement properties remain unknown therefore, a rigorous cross-cultural validation is necessary. ObjectiveTo translate and cross-culturally adapt the MBBQ into Brazilian Portuguese and investigate its measurement properties. MethodsThe MBBQ was translated and cross-culturally adapted into Brazilian Portuguese. In the final stage of the cross-cultural adaptation process, the translated version was tested with 30 physical therapists to check the understanding of each item. Then, we evaluated the measurement properties in a sample of 100 physical therapists. We calculated test-retest reliability, internal consistency, standard error of the measurement (SEM) and minimal detectable change (MDC). The Pain Attitudes and Beliefs Scale for Physiotherapists (PABS.PT) was used in the construct validity analysis. ResultsThe reliability analysis showed high internal consistency, good to excellent test-retest reproducibility. Cronbach alpha coefficient for the MBBQ inevitability score was 0.80 and for the composite score 0.89. Intraclass correlation coefficient (ICC) for the Inevitability score was 0.67 (95%CI: 0.55 to 0.77) and 0.79 (95%CI: 0.70 to 0.86) for the composite score. The MBBQ inevitability and composite scores showed SEM of 1.9 and 2.4 points and minimal detectable change (MDC) of 5.1 and 6.7 points, respectively. Construct validity analyses showed moderate to excellent correlation of the MBBQ scores and the biomedical subscale of the PABS.PT. ConclusionsMBBQ showed acceptable measurement properties and may be considered a reliable and valid tool to assess physical therapists' beliefs about low back pain.