Development of a valid simplified Chinese version of the Osteoarthritis of Knee and Hip Quality of Life (OAKHQOL) in patients with knee or hip osteoarthritis

Rationale, aims and objectives As the first specific questionnaire for knee or hip osteoarthritis (OA) patients' condition assessment, the Osteoarthritis of Knee and Hip Quality of Life (OAKHQOL) questionnaire is widely used and its original version is French. Although it has already been translated into multiple languages, a Chinese version is still unpublished, despite the fact that China has the largest population of OA patients in the world. The objectives of our study were to adapt the OAKHQOL questionnaire into simplified Chinese and to assess its psychometric properties in Chinese patients with knee or hip OA. Methods First, we developed the simplified Chinese version of OAKHQOL (SC-OAKHOQL) in a five-step procedure of translation and cross-cultural adaptation. Next, we calculated the Cronbach's alpha, intraclass correlation coefficient (ICC), Pearson's correlation coefficient (r), effect size (ES) and standardized response mean (SRM) to evaluate the reliability, validity and responsiveness of the SC-OAKHQOL, respectively. Unidimensionality of subscales was assessed by the principal component analysis (PCA) of residuals. Results Overall, 144 knee or hip OA patients successfully completed all of the questionnaires. Excellent or good internal consistency (alpha=0.826-0.964) was found in the SC-OAKHQOL, as well as excellent test-retest reliability (ICC=0.888-0.944). Good correlations were also obtained among physical subscales (r=0.646-0.934), as well as mental subscales (r=0.786-0.874) in the SC-OAKHQOL and other questionnaires, on which excellent or good validity of the SC-OAKHQOL shall be based. With the exception of the social support subscale, all others contained excellent or good responsiveness (ES, SRM=1.02-2.92). The unidimensionality of five subscales was respected according to the PCA of residuals. Conclusion The SC-OAKHQOL questionnaire is reliable, valid and responsive for the evaluation of Chinese osteoarthritis patients of the knee or hip, and it would be an effective instrument.