Internal consistency, reproducibility, responsiveness, and construct validity of the Chinese (HK) version of the asthma quality of life questionnaire

Abstract

The purpose of this study was to test the acceptability, psychometric properties and construct validity of a Chinese translation of the Asthma Quality of Life Questionnaire (AQOL) and to determine whether it has any advantage over the Chinese (HK) version of the generic MOS SF-36 Health Survey that has been validated on Chinese in Hong Kong. Fifty-two patients with asthma were interviewed using the Chinese (HK) AQOL and the Chinese (HK) SF-36. Thirty-four of the 52 patients were interviewed a second time 6 months later using the same questionnaires. The Cronbach's α coefficients were above 0.7 for all four domains of the AQOL questionnaire. Significant correlations were found between the scores of each of the four domains of the Chinese (HK) AQOL and forced expiratory volume in 1 s (FEV1) (%predicted) during the initial visit and between changes in the mean scores of most of the domains of Chinese (HK) AQOL and changes in FEV1 between visits. The Chinese (HK) AQOL was found to be reproducible in those with stable asthma, and for those whose asthma severity changed between visits, there was significant change in one of the domains. It can detect differences in quality of life in asthma patients of varying severity. We conclude that the Chinese (HK) translation of the AQOL is reliable, valid, reproducible and discriminative and can be used to supplement generic instruments in evaluating the quality of life of patients with asthma.