ObjectivesTo analyze the effect of bronchiectasis (BE) on the clinical characteristics and prognosis of hospitalized patients with community acquired pneumonia (CAP), and to explore the independent risk factors affecting the 30-day mortality. MethodsA national multi-center retrospective study based on the CAP-China network platform. The clinical data of 6056 patients with CAP who were hospitalized in 13 tertiary teaching hospitals in Beijing, Shandong and Yunnan from January 1, 2014 to December 31, 2014 were collected. To compare the differences in clinical characteristics, etiological distribution and treatment prognosis of patients with CAP with bronchiectasis (BE-CAP) and patients without bronchiectasis (non-BE-CAP). Logistic regression analysis was performed to analyze independent risk factors affecting 30-day mortality in hospitalized patients with BE-CAP. ResultsIn the final analysis, 5880 CAP patients were included, and BE-CAP patients accounted for 10.8% (637/5880). Compared with non-BE-CAP patients, more BE-CAP patients were women, and a higher proportion of patients had chronic obstructive pulmonary disease, bronchial asthma, previous history of glucocorticoid inhalation, and a history of CAP within 1 year. BE-CAP patients had more dyspnea and cyanosis, lower arterial partial pressure of oxygen, longer median time to clinical stability (6 d vs. 4 d, P<0.001), and the incidence of respiratory failure was significantly higher than that of non-BE-CAP patients (27.8% vs. 19.7%, P<0.001). Pseudomonas aeruginosa is the most common bacterial infection in BE-CAP patients. Comorbid bronchiectasis has no significant effect on disease severity, total length of hospital stay, and mortality in CAP patients. The 30-day mortality rate of BE-CAP patients was 2.2%. Logistic regression analysis showed that initial treatment failure [odds ratio (OR) 6.675, 95% confidence interval (CI) 4.235-10.523, P<0.001], respiratory failure (OR 5.548, 95%CI 3.681-8.363, P<0.001), blood urea nitrogen>7.0 mmol/L (OR 2.490, 95%CI 1.625-3.815, P<0.001), albumin<35.0 g/L (OR 1.647, 95%CI 1.073-2.529, P=0.022) and CURB-65 score (OR 1.691, 95%CI 1.341-2.133, P<0.001) were independent risk factors for 30-day mortality in BE-CAP patients. ConclusionsBE-CAP patients have more serious hypoxia symptoms and higher incidence of respiratory failure. For BE-CAP patients with failure of initial treatment, complicated with respiratory failure, blood urea nitrogen>7.0 mmol/L, and albumin<35.0 g/L, treatment evaluation should be performed in time to reduce the mortality rate.