Development and Validation of the COPD Scale among the System of Quality of Life Instruments for Chronic Diseases QLICD-COPD (V2.0)

Background: Chronic obstructive pulmonary disease (COPD) is a chronic disease with high mortality and severe morbidity that keep increasing the burden of the health of the population. Chronic Obstructive Pulmonary Disease (QLICD-COPD) (V2.0) was used to measure the quality of life for patients with COPD. The study aimed to develop the instruments to evaluate a quality-of-life questionnaire for COPD. Methods: The questionnaires were developed after reviewing the literature and three hundred and twenty-one patients with COPD were evaluated by a series of statistical methods consisting of the paired t-test, correlation analysis, and factor analysis. Results: The overall Cronbach’s alpha coefficient was 0.889 (greater than the accepted reference value of 0.7), and the coefficients of most domains and facets were in the range 0.6 to 0.88, except some facets of psychological domain and social domain. The split-half reliability coefficients of the domains and the total scale is greater than 0.6 apart from the physiological domain. Intra-domain internal consistency coefficients were higher than inter-domain correlation coefficients and each item was more strongly correlated with its domain than with other domains. SF-36 domains with high reliability and validity closed linked with the scores of QLICD-COPD (2.0) except the general health and social domains. The paired t -test showed significant changes in the scores of most domains after treatment with P<0.001, and the domains and facets with significant score changes after treatment obtained relatively large standardized response mean(SRM). Conclusion: The QLICD-COPD (V2.0) questionnaire shows good reliability, validity, and responsiveness, and can serve as an instrument for evaluating the quality of life of patients with COPD in China.