Prognostic determinants in AECOPD differ by cardiovascular disease status: a two-center retrospective cohort study in China

Cardiovascular disease (CVD) comorbidity is common among patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and is associated with poor prognosis. However, whether the presence of CVD modifies the prognostic determinants in AECOPD remains unclear, and there is a lack of validated risk stratification tools that account for this heterogeneity, particularly in China. This retrospective cohort study enrolled 1584 patients hospitalized for AECOPD from two centers in China. Patients were classified as CVD or non-CVD based on prespecified cardiovascular conditions. Cause-specific mortality was analyzed using data linked to the National Mortality Surveillance System. The primary outcome was overall survival from index hospitalization (OS1). OS2 (from first symptom onset) was analyzed as an exploratory outcome. Hospitalization duration was modeled using negative binomial regression. The models were developed in the Beijing cohort (70% training/30% internal test) and externally validated in the Jilin cohort. Respiratory-related death was the predominant cause across all subgroups, accounting for approximately half of all deaths. Compared with non-CVD patients, those with CVD had significantly longer hospital stays (8.71 days vs 7.98 days, P < 0.001) and worse long-term survival (3-year OS1 rate: 76.6% vs. 85.4%, P < 0.001). External validation demonstrated moderate discrimination for the CVD model of OS1 ( C-index : 0.700, 95% CI 0.611–0.773) and non-CVD model of OS1 ( C-index : 0.662, 95%CI 0.565–0.744). Sensitivity analysis including hypertension in the CVD definition and filtering early death yielded consistent results. Our findings suggest that prognostic determinants differ substantially between CVD and non-CVD groups, supporting a hypothesis-generating framework for stratified risk assessment. A stratified prognostication framework in which CVD status dictates the use of different risk calculators was built and paved the way for more practical management strategies in China.