Elevated troponin level as a predictor of inpatient mortality in patients with infective endocarditis in the Southeast United States

Abstract

Background: Despite recent improvement in management, infective endocarditis (IE) continues to be associated with considerable risk of morbidity and mortality. Early identification of predictors of inpatient mortality is key in improving patient outcomes in IE. The aim of our study was to evaluate the role of serum troponin levels measurements as a marker of increased mortality. Methods: A case-control study included adult patients with IE admitted to a tertiary care hospital in east Tennessee between December 2012 and July 2017. Cases were defined as patients with definitive IE who died in-hospital; controls were patients who did not die in hospital. First patient admission was included only. Data collected included the patients' demographic and baseline clinical information, microbiological data, injection drug use status, elevated serum troponins levels. Results: Two hundred eighty three patients with definitive IE were included; median (IQR) age was 41 (30-57) years, and 153 (54%) patients were men. One-hundred sixty-four (58%) were injection drug users. The most frequent IE type was: 167 (59%) right-sided, 86 (30%) left-sided, 24 (9%) both left and right-sided, and 10 (4%) device related. The most commonly isolated organism was Staphylococcus aureus (n = 141), and 64% were methicillin-resistant. Two-hundred twelve (75%) patients had a troponin level obtained, and 57 (27%) had an elevated troponin value. Thirty-six (13%) patients died in-hospital; in-hospital mortality was associated elevated troponin values (adjusted odds ratio [adjOR], 7.3; 95%CI, 3.3-15.9), and methicillin-resistant S. aureus IE (adjOR 2.6; 95%CI, 1.2-5.8). Forty-four (16%) patients received IE valve surgery, and none of these patients died in the hospital. Conclusion: Inpatient mortality was higher in patients with IE and elevated cardiac troponin levels compared to patients with normal levels.