In-hospital mortality after concomitant pneumonia in acute coronary syndrome

Abstract

Introduction
Pneumonia may complicate acute coronary syndrome (ACS), but its association with mortality during ACS hospitalization requires further characterization. This study evaluated the prevalence of concomitant pneumonia and its adjusted association with in-hospital all-cause mortality in patients with ACS.

Methods
This retrospective cohort study included 494 adults admitted with ACS between November 2022 and November 2023. Pneumonia was identified during the index hospitalization. Univariable and multivariable logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) for mortality. Exploratory analyses assessed pneumonia-by-ACS-subtype interactions and adjusted associations with log-transformed length of stay. Adjustment included demographic characteristics, ACS subtype, and recorded clinical conditions. A sensitivity analysis of hospitalization duration was restricted to patients who survived to discharge.

Results
Pneumonia was identified in 99 patients (20.0%); 171 patients (34.6%) died during hospitalization. Mortality was higher with pneumonia than without pneumonia (63.6% vs. 27.3%; crude OR 4.65, 95% CI 2.92–7.41; p<0.001). After adjustment, pneumonia remained associated with mortality (adjusted OR 9.69, 95% CI 5.18–18.13; p<0.001). There was no evidence of interaction with ACS subtype (p=0.787). Median hospital stay was longer with pneumonia (9 vs. 6 days; p<0.001), consistent with the adjusted analysis (geometric mean ratio 1.49, 95% CI 1.38–1.60; p<0.001).

Conclusions
Concomitant pneumonia affected one in five patients with ACS and was associated with substantially higher adjusted odds of in-hospital mortality and longer hospitalization. These findings support careful assessment for pneumonia during ACS care. Prospective studies recording infection onset and illness severity are needed to clarify the temporal relationship and evaluate management strategies.