Development and validation of the French ASQoL questionnaire.

OBJECTIVES Ankylosing spondylitis (AS) is a chronic condition with significant impact on quality of life. The objective was to cross-culturally adapt into French and validate the ASQoL, an 18-item disease-specific self-report questionnaire. METHODS Cross-cultural adaptation according to published guidelines used forward and backward translations, with an emphasis on expert committee informed decision making. A sample of active AS French patients answered the questionnaire twice, two weeks apart. A transition question helped identify those with no or some change over time. RESULTS Cross-cultural adaptation resulted in rewording outcome categories from yes/no into true/false to better suit the French context. In 139 patients (mean age 40.9 years, 54.6% males) with active disease (mean BASDAI 4.8), the mean ASQoL score was 10.0. A 2-parameter Rasch model confirmed unidimensionality (chi-square fit p=0.86) with good item discrimination. Internal consistency was high (Cronbach's alpha 0.9). Convergent validity was ascertained by high correlation of ASQoL score with disease activity measures (r=0.57 to 0.79). Test-retest reproducibility was satisfactory (ICC 0.89). Responsiveness was moderate (SRM 0.44) in patients improving and good (SRM 0.68) in patients worsening over the period. CONCLUSIONS These results show equivalence in content and validity of the cross-culturally adapted ASQoL for French speaking settings.