Impact of Elevated Troponins on Mortality of ICU Patients

Abstract

Introduction: Myocardial injury as evidenced by elevated cardiac troponin levels may occur in 7-36% of hospitalized patients with coronavirus 2019 (COVID-19). Studies have shown that COVID-19 patients with elevated cardiac troponin are more likely to require the intensive care unit (ICU) and mechanical ventilation and have a higher risk of death. However, studies on the impact of elevated troponins at the time of hospital admission on mortality of ICU patients are limited. Here we aim to characterize, compare, and analyze COVID-19 patients in our institution's ICUs who had elevated troponins. Methods:This study is a retrospective analysis of adult patients with COVID-19 admitted to the ICUs of a tertiary care hospital between 03/01/2020 and 05/31/2020. Myocardial injury was defined as troponin ≥ 0.04 ng/mL. Only patients who had troponins measured within 24 hours of hospital admission were included. We excluded patients with a past medical history of chronic kidney disease (CKD) or end-stage renal disease (ESRD). We also excluded those patients who were transferred to our ICU from another hospital and where admission labs from the transferring institution were not available for our review. We compared the clinical characteristics and outcomes of critically ill COVID-19 patients who had elevated troponins with those who did not.Results: Of the 210 patients admitted with COVID-related Acute Respiratory Distress Syndrome, 178 had troponin measured within 24 hours of hospital admission. 25 patients had a past medical history of CKD or ESRD and 11 patients were transferred from another hospital with no labs available from their day of admission. Of the 142 remaining patients, 72 (50.7%) had an elevated troponin while 70 (49.9%) had a normal troponin at presentation. Patients with elevated troponins were older (67.5 ± 15.1 vs 60.2 ± 14.2), and predominantly male (72.2% vs. 54.3%). Inflammatory markers were significantly elevated in both groups but not statistically different. Therapies provided were similar in both groups. Most importantly, patients with an elevated troponin had significantly increased risk of mortality compared to those with a normal troponin at admission (55.6% vs. 34.3%).Conclusion: Our results suggest that myocardial injury is a common occurrence in COVID-19 patients requiring ICU admission. Additionally, mortality in this population is significantly higher further indicating myocardial injury as a predictor of mortality. To determine if elevated troponin levels are independent of other risk factors for mortality in COVID-19 such as age, and gender will need to be determined in future studies.