The short version of the World Health Organization's Quality of Life Instrument (WHOQOL-BREF) is widely validated and popularly used in assessing the subjective quality of life (QOL) of patients and the general public. We examined its psychometric properties in a large sample of community residents in mainland China.
The WHOQOL-BREF was administered to 1052 adult community residents in a major metropolitan city in southern China. The structural integrity of the 4-factor model in confirmatory factor analyses (CFA) and the relationship of QOL with demographic variables were examined. Validity was assessed using the known-group comparison (229 with vs. 823 without chronic illness), item-domain correlations, and CFA using the ML estimation in LISREL.
Internal consistency reliability of the whole instrument (26 items) was 0.89, and the psychological, social, and environment domains had acceptable reliability (alpha = 0.76, 0.72, 0.78 respectively), while that of the physical domain was slightly lower (α = 0.67). The respective mean scores of these domains were 13.69, 14.11, 12.33 and 14.56. Item-domain correlations were much higher for corresponding domains than for non-corresponding domains, indicating good convergent validity. CFA provided a marginally acceptable fit to the a priori four-factor model when two matching content item pairs were allowed to be correlated; χ2 (244) = 1836, RMSEA = 0.088, NNFI = 0.898, CFI = 0.909. This factorial structure was shown to be equivalent between the participants with and without chronic illness. The differences in means between these two groups were significant but small in some domains; effect size = 0.55, 0.15, 0.18 in the physical, psychological, and social relationship domains respectively. Furthermore, males had significantly higher QOL scores than females in the psychological domain, while individuals with a younger age, higher income, and higher education levels also had significantly higher QOL. Compared with the international data, the Chinese in this study had relatively low QOL scores with about 5% of males and 16% of females being at risk for poor QOL.
This study has provided psychometric properties of the WHOQOL-BREF as used in China and should definitely be useful for researchers who would like to use or further refine the instrument.