The Risk of Adverse Cardiac Events Following Pneumonia in Patients with Coronary Artery Disease.

Abstract

Rationale: Pneumonia triggers an inflammatory response that can persist beyond resolution of infection. This may increase the risk of major adverse cardiac events (MACE) in people with known coronary artery disease (CAD).

Objectives: To assess the impact of pneumonia on MACE in individuals with pre-existing CAD.

Methods: We identified patients who had coronary artery revascularisation procedures in 7 major hospitals in Western Australia between 2000-2005. Multivariable Cox regression models assessed the association between time-dependent pneumonia and MACE [composite of all-cause death + myocardial infarction (MI) + unstable angina + ischemic stroke + heart failure (HF)] and component outcomes separately, over 30 days, 1 year, and full follow-up.

Measurements: There were 14,425 patients in the study cohort (mean age 64.4, 23.6% female). Over a maximum of 13-years follow-up, 988 patients experienced ≥1 pneumonia hospitalisation.

Main results: The risk of MACE increased over time, with adjusted hazard ratios (aHR) of 4.91 (95% CI 1.21-20.00) and 4.91 (CI 2.62-9.19) over 30-day and 1-year intervals, respectively, and an aHR of 11.41 (CI 9.22-14.11) over the entire follow-up. MI risk was highest during the first 30 days (aHR 11.34) and reduced over the 1-year interval and remainder of follow-up (aHR 2.27 and 2.63, respectively). Risk of HF and cardiovascular death were also high over the entire follow-up period (aHR 10.39 and 12.25, respectively).

Conclusions: Pneumonia hospitalisation significantly increases short- and long-term risk of MACE in CAD patients. Underlying mechanisms should be better understood to develop targeted interventions to reduce MACE in this already high-risk population.