Predictive Value of CCQ and its Subdomains for Hospitalized Exacerbations in Chronic Obstructive Pulmonary Disease: A 3-Year Observational Prospective Study

Background: The prediction capacity of the Clinical COPD Questionnaire (CCQ) and its functional, symptom, and mental subdomain for COPD hospitalized exacerbation were rarely studied. Objective: To examine the prognostic capacity of the total CCQ and its three subdomains for 3-year COPD hospitalized exacerbations. Methods: We analyzed the predictive ability of total CCQ score and its subdomains for hospitalized exacerbations in an observational cohort of 987 subjects with stable COPD from the RealDTC, an ongoing multicenter prospective study. Hospitalized exacerbations were prospectively collected every 6 month for a maximum of 3 years. Results: The total CCQ and its functional and symptom domain, but not the mental domain, were significantly associated with 3-year hospitalized exacerbations by multivariate Cox regression analysis. The predictive capacity of functional domain was similar to that of the total CCQ, but significantly stronger than the symptom and mental domain by ROC analysis (P < 0.05). ROC curves also showed that the AUC of exacerbation history combined with CCQ functional domain was larger than that of exacerbation history alone (P < 0.0001). Additionally, the predictive value of multivariable models that contains CCQ functional domain was significantly better than the corresponding model without CCQ functional domain (P < 0.05). Conclusions: The total CCQ and its functional and symptom domain were independent risk factors of 3-year hospitalized exacerbations. The prognostic capacity of the functional domain was similar to that of total CCQ, and was significantly stronger than the symptom and mental domain. The CCQ functional domain was able to increase the predictive power of exacerbation history and other multivariable prediction models, indicating it may have an important role in the multivariable prediction tool for hospitalized exacerbation, and its combination with other clinical variables might be used as a low-cost approach for assessments of the disease severity and severe exacerbation in COPD patients in the future.