Psychometric properties of a Chinese asthma quality of life questionnaire

To assess the acceptability, reliability, validity, and responsiveness of the Chinese Asthma Quality of Life Questionnaire (C-AQLQ) in a sample of Chinese asthma patients.

The C-AQLQ and Short Form 36 Health Survey (SF-36) scales were administered to patients at baseline and 3 months later. Asthma severity condition and lung function were evaluated. Necessary data were gathered to assess the psychometric properties such as the feasibility, internal consistency, test-retest reliability, structural validity, discriminant validity, convergent validity, and responsiveness of the C-AQLQ.

One hundred and thirty-seven patients completed the investigation. The Cronbach's alpha coefficient for the total scale was 0.96. Factor analysis yielded five factors that generally corresponded to the five proposed subscales. Patients with mild asthma reported higher scores than patients with moderate/severe asthma on all subscales other than environmental stimuli. Lung function measurement and the asthma severity score correlated significantly with domains of the C-AQOL but with fewer domains of the SF-36. The questionnaire detected within-subject changes in patients' asthma status during follow-up.

Results indicated preliminary support that the C-AQLQ is a reliable, valid, discriminating, and responsive measure of quality of life in Chinese asthma patients. It is more sensitive than the generic SF-36 in detecting differences in asthma severity.