Being hospitalized for ACS worsens long-term risk of pneumonia

Hospitalization for acute coronary syndrome (ACS) appears to exacerbate the long-term risk of pneumonia, a recent South Korea study has found.

Drawing from a nationally representative database, the researchers conducted a matched-cohort study including 5,469 patients admitted for ACS without a history of either ACS or pneumonia. Each enrolled case was matched to three randomly selected controls, who were also free of ACS and pneumonia, matched by age and sex.

Log-rank analysis revealed that the primary outcome of first pneumonia event occurred significantly more frequently in the ACS hospitalization group than in controls. Cox-regression analysis confirmed that exposure to ACS significantly increased the risk of first-incidence pneumonia by 25 percent (hazard ratio [HR], 1.25, 95 percent confidence interval [CI], 1.09–1.42; p=0.001).

To account for the multiple times that pneumonia can develop in an individual and for death, the researchers constructed two additional statistical models: a shared frailty model factoring multiple recurrences and a joint frailty model that accounts for recurrences and deaths due to pneumonia.

In both additional models, ACS hospitalization associated significantly with an increased long-term risk of pneumonia (HR, 1.35, 95 percent CI, 1.15–1.58; p<0.001 and HR, 1.24, 95 percent CI, 1.10–1.39; p<0.001, respectively).

Other potential predictors of long-term pneumonia risk were age, sex, body mass index, smoking, and comorbidities like stroke, heart failure, and chronic obstructive pulmonary disease.

Findings in the present study “should be considered when formulating postdischarge care plans and preventive vaccination strategies in patients with ACS,” said the researchers.