Cultural adaptation and validation of a German version of the Arthritis Impact Measurement Scales (AIMS2).

OBJECTIVE: To validate a translated and culturally adapted version of the Arthritis Impact Measurement Scale (AIMS) 2 in primary care patients with osteoarthritis (OA) of the hip and knee. METHOD: The AIMS2 was translated into German and culturally adapted. The questionnaire then was administered to 220 primary care patients with OA of the knee or hip. Two hundred and nine questionnaires were returned and analysed. Test-retest reliability was tested in 50 randomly selected patients, of those 42 completed the questionnaire after 2 weeks for a second time. RESULTS: Item-scale correlations were reasonably good as well as the discriminative power of separate scales. The assessment of internal consistency reliability also revealed satisfactory values; Cronbach's alpha was 0.77 or higher for all scales. The test-retest reliability, estimated in an intraclass correlation coefficient (ICC), exceeded 0.90, except the "social activities" scale (0.87). Since only patients with OA of the lower limb were enrolled, substantial floor effects occurred in the "arm function" (28.2%) and the "hand and finger function" scale (29.2%). The principal factor analysis confirmed the postulated three-factor structure with a physical, physiological and social dimension, explaining 48.5%, 13.9% and 6.8% of the variation, respectively. External validity was assessed by calculating correlations to the Western Ontario and MacMaster (WOMAC) osteoarthritis questionnaire a pain visual analogue scale (VAS) and the Kellgren score as well as to disease duration. Spearman's "R" achieved satisfactory values for the corresponding WOMAC scales and the pain-VAS. Correlations with disease duration as well as with the radiological grading were low. CONCLUSION: The GERMAN-AIMS2 is a reliable and valid instrument to assess the quality of life (QoL) in primary care patients suffering from OA