ObjectivesTo explore the clinical characteristics and risk factors for 30-day mortality of community-acquired pneumonia (CAP) patients with chronic obstructive pulmonary disease (COPD).MethodsThis was a multicentre, retrospective study. Data of patients hospitalized with CAP from four tertiary hospitals in Beijing, Shandong and Yunnan from January 1, 2013 to December 31, 2015 were reviewed. Patients with (COPD-CAP) and without (non COPD-CAP) COPD were compared, including demographic and clinical features, treatment and outcomes. Univariate analysis and multivariate Logistic regression analysis were performed to identify risk factors for 30-day mortality in COPD-CAP patients.ResultsThree thousand three hundred and sixty-six CAP patients were entered into final analysis, COPD-CAP accounted for 12.9% (435/3 366). Compared to non COPD-CAP patients, COPD-CAP patients were more male and more frequent with CURB-65 score 2 and pneumonia severity index (PSI) risk class Ⅲ to Ⅴ. Pseudomonas aeruginosa was the most common etiology and more common in COPD-CAP patients than non COPD-CAP patients. Though the proportion of respiratory failure and heart failure were higher in COPD-CAP patients, there was no significant difference in the 30-day mortality. The 30-day mortality of COPD-CAP patients was 5.7% (25/435). Logistic regression analysis confirmed aspiration (OR 9.505, 95%CI 1.483 - 60.983, P=0.018), blood procalcitonin ≥2.0 ng/mL (OR 5.934, 95%CI 1.162 - 30.304, P=0.032) and PSI risk class (OR 2.533, 95%CI 1.156 - 5.547, P=0.020) were independent risk factors for 30-day mortality in COPD-CAP patients.ConclusionsCOPD-CAP patients present specific characteristics. Besides PSI risk class, clinicians should pay high attention to the aspiration and blood procalcitonin, which could increase the 30-day mortality in COPD-CAP patients.