Psychometric properties of the Polish version of the 36-item WHODAS 2.0 in patients with hip and knee osteoarthritis.

Purpose To examine psychometric properties of the Polish version of the 36-item WHO Disability Assessment Schedule 2.0 (WHODAS 2.0) in the population with hip and knee osteoarthritis (OA). Methods This was a longitudinal study with repeated measures during retest examinations. Subjects from a Polish Specialist Hospital (age = 68.3 ± 9.2years, 71% female, 44.2% knee OA, 55.8% hip OA) were tested three times. They completed the Polish version of the 36-item WHODAS 2.0, the SF-36 Health Survey 2.0, the Western Ontario and Macmaster Universities Osteoarthritis Index 3.1, the Hospital Anxiety and Depression Scale, and the Numerical Rating Scale. Results The 36-item WHODAS 2.0-Polish version demonstrated high internal consistency (Cronbach's alpha for total = 0.94), and test-retest reliability (Total ICC2,1 = 0.98). High construct validity was found as 12 out of 15 a priori hypotheses (80%) were confirmed. Most domains and Total Scores in the 36-item WHODAS 2.0 (Total ES = - 0.62, SMR = - 1.09) showed a moderate degree of responsiveness. Minimal clinically important difference (MCID) for the Total WHODAS 2.0 was 3.29 in patients undergoing rehabilitation for knee or hip OA. Conclusions The Polish version of the 36-item WHODAS 2.0 assesses disability according to ICF in a reliable, valid and responsive way. Therefore, it provides considerable support in clinical practice and national and international scientific research of patients with hip or knee OA.