Psychometric properties of the Chinese quality of life instrument (HK version) in Chinese and Western medicine primary care settings

BACKGROUND: The Chinese Quality of Life Measure (ChQOL) had only been validated on a small number of selected subjects in Hong Kong and had never been tested in the Western medicine (WM) primary care setting. AIMS AND OBJECTIVES: To test the psychometrics properties of ChQOL(HK version) in both TCM and WM general outpatient clinics. METHODS: Three samples of Chinese adult patients [(1) 569 consulting TCM clinics for episodic illnesses; (2) 524 consulting WM clinics for episodic illnesses; (3) 205 consulting WM clinics for chronic disease follow-up] in Hong Kong were invited to complete the ChQOL(HK version) and the SF-36 Health Survey during their consultations and 2 weeks after consultations. The scaling assumptions, factor structure, convergent construct validity, reliability, responsiveness, and discriminatory power of the ChQOL were evaluated. RESULTS: Majority of items satisfied the scaling assumptions. A two instead of 3-factor structure was found with physical form and emotion facets loading on one factor. Convergent construct validity was confirmed with moderate correlations with SF-36 scores. Internal consistency and test–retest reliability were satisfactory. The ChQOL(HK version) was able to detect significant improvements 2 weeks after consultations, and it was able to discriminate between groups with different illness severity, age, and sex. CONCLUSION: The ChQOL(HK version) was shown to have satisfactory validity, reliability, discriminatory power, and responsiveness in both TCM and Western medicine primary care settings. The validity of the 3-domain scaling structure needs further evaluation.