Brazilian-Portuguese version of the Health Assessment Questionnaire for Spondyloarthropathies (HAQ-S) in patients with ankylosing spondylitis:: a translation, cross-cultural adaptation, and validation

To translate and cross-culturally adapt to the Brazilian-Portuguese language (BP), five items were added to Health Assessment Questionnaire (HAQ) to validate the resulting HAQ-S BP version for ankylosing spondylitis (AS). The items were translated into BP following translation and back-translation. To assess validity, 25 patients were evaluated using the HAQ, Bath AS Functional Index (BASFI), Bath AS Disease Activity Index (BASDAI), Bath AS Metrology Index (BASMI), and laboratory variables (erythrocyte sedimentation rate, C-reactive protein). One question required modification to adapt culturally to Brazilian conditions. The test-retest and interobserver correlation coefficients were 0.990 (p < 0.05) and 0.993 (p < 0.05), respectively. HAQ-S BP correlated to BASFI (r=0.574; p < 0.05) and to HAQ (r=0.963; p < 0.05), but not to BASDAI (r=0.282), BASMI (r=0.194), and laboratory variable. Individually, the fifth item referring to driving correlated highly to neck rotation (r=0.900; p < 0.05), while the HAQ-S BP correlated to the neck rotation component (r=0.303), but did not reach statistical significance. The HAQ-S BP version demonstrated adequate reproducibility, internal consistency and validity, confirming its utility in the research of AS in Brazil.