Objective: The Animated Activity Questionnaire (AAQ) assesses activity limitations in patients with hip/knee osteoarthritis (HKOA), and consisting video animations of which patients choose the animation that best matches their own performance. The AAQ has shown good validity and reliability. This study aims to evaluate cross-cultural and construct validity of the AAQ.
Methods Cross-cultural validity was assessed using ordinal logistic regression analysis to evaluate Differential Item Functioning (DIF) across 7 languages. Construct validity was assessed by testing correlations between the AAQ, and a Patient Reported Outcome Measure (PROM) and performance-based tests.
Results: Data of 1239 patients were available. Compared to Dutch (n=279), none of the 17 items showed DIF in English (n=202), French (n=193), 1 item showed uniform DIF in Spanish (n=99) and Norwegian (n=62), and 2 items showed uniform DIF in Danish (n=201). In all these languages, the occurrence of DIF did not influence the total score, which remained comparable with the original Dutch version. For Italian (n=203) versus Dutch however, 6 items showed uniform DIF, and 1 item showed non-uniform DIF, indicating some problems with the cross-cultural validity between these countries. With regard to construct validity, the correlations with PROM (0.74) and performance-based tests (0.36-0.68) were partly as expected (> 0.60).
Conclusion: The AAQ, an innovative tool to measure activity limitations that can be placed on the continuum between PROMs and performance-based tests showed a good overall cross-cultural validity, and seems to have great potential for international use in research and daily clinical practice in many European countries.