Measurement Properties of Two Questionnaires Assessing Fear-Avoidance in Patients With Chronic Low Back Pain.

The Fear-Avoidance Components Scale (FACS) and the Fear of Daily Activities Questionnaire (FDAQ) assess fear-avoidance model components. However, the questionnaires are not available in Brazilian Portuguese. This study aimed to translate the original English FACS and FDAQ into Brazilian (Br) Portuguese and assess their measurement properties in patients with Chronic Low Back Pain (CLBP). One hundred thirty volunteers with CLBP participated in this study. Structural validity, internal consistency, test-retest reliability, and hypothesis testing for construct validity were analyzed. Results indicated a 2-factor solution for the FACS-Br, while the FDAQ-Br had a one-factor solution. Internal consistency showed acceptable Cronbach's alpha (alpha >.8). Suitable reliability was found for the FDAQ-Br (Intraclass Correlation Coefficient [ICC] = .98). For both FACS-Br factors, suitable reliability was found as well (ICC = .95 and .94). Hypothesis testing for construct validity confirmed more than 75% of the hypotheses proposed a priori for the FACS maladaptive pain/movement-related beliefs domain and the FDAQ-Br. In conclusion, the FACS-Br and FDAQ-Br demonstrated acceptable reliability, internal consistency, and structural validity measurement properties and their correlation (r < .50) suggests that the tools are not interchangeable measures.