ObjectiveTo compare the predictive value of the BAP-65 score, the DECAF score, the CURB-65 score, and the Pneumonia Severity Index (PSI) on short-term mortality and adverse outcomes in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with community-acquired pneumonia (CAP). MethodsThis study enrolled patients hospitalized for AECOPD and CAP from ten hospitals in China from September 2017 to July 2021. All-cause mortality within 30 days was investigated. Patients were divided into the death and the survival groups according to their survival status. The differences in basic conditions, complications, symptoms, signs and auxiliary examination results between the two groups were compared, and the independent risk factors of all-cause mortality were analyzed. The included patients were scored and graded according to the 4 scales, respectively, and the validity of the four scales in predicting short-term mortality and adverse outcomes was compared based on the receiver operating charateristic (ROC) curve analysis. ResultsA total of 3375 patients including 2545 males and 830 females with a mean age of (73.66 ±10.73) years were enrolled in this study. Within 30 days, 129 (3.82%) patients died and 614 (18.19%) patients had an adverse outcome (including all-cause death, invasive mechanical ventilation and admission into intensive care unit). Altered state of consciousness, diabetes mellitus, atrial fibrillation, chronic pulmonary heart disease, age, pulse rate, serum albumin, diastolic blood pressure, and pH value were independent risk factors for 30-day mortality in AECOPD patients with CAP. The area under the ROC curve (AUC) of the CURB-65 score, BAP-65 score, DECAF score, and PSI score for predicting all-cause mortality were 0.780, 0.782, 0.614, and 0.816, and these AUCs for predicting adverse outcomes were 0.694, 0.687, 0.564 and 0.705, respectively. PSI score had the best predictive efficacy for all-cause mortality and adverse outcomes, and the DECAF score had the worst predictive efficacy. ConclusionsAECOPD patients with CAP have a relatively high incidence of all-cause mortality and adverse outcomes within 30 days. Altered state of consciousness, diabetes mellitus, atrial fibrillation, chronic pulmonary heart disease, age, pulse rate, serum albumin, diastolic blood pressure, and pH value are independent risk factors for 30-day mortality. PSI score has the best performance in predicting all-cause mortality and adverse outcomes, while the DECAF score has the worst performance.