Elevated cardiac troponin is an independent risk factor for short- and long-term mortality in medical intensive care unit patients

Abstract

Background: Troponin elevations are common in critically ill patients. Whether they are predictors of mortality independent of the severity of the underlying disease is unclear.

Objective: To determine whether troponin elevations predict in-hospital, short-term, and long-term mortality in medical intensive care unit patients independent of the severity of the underlying disease as measured by Acute Physiology and Chronic Health Evaluation III prognostic system.

Design: Retrospective study.

Setting: We examined the Acute Physiology and Chronic Health Evaluation III database and cardiac troponin T levels of medical intensive care unit patients at Mayo Clinic, Rochester, MN.

Patients: In all, 1,657 patients consecutively admitted to medical intensive care units between August 2000 and December 2001.

Measurements: In-hospital, short-term (30-day), and long-term all-cause mortality.

Results: During hospitalization, 12.5% of patients with a cardiac troponin T < 0.01 microg/L suffered deaths compared with 29.5% among those with cardiac troponin T > or = 0.01 microg/L (p < .001). At 30 days, mortality was 13.7% without and 34.6% with elevations (p < .001). The expected probability of survival at 1-, 2-, and 3-yr follow-up was 43.7%, 33.8%, and 25.7% among patients with cardiac troponin T > or = 0.01 microg/L and 75.3%, 67.6%, and 62.9% in those with cardiac troponin T < 0.01 microg/L, respectively (p < .001). After adjustment for the severity of disease and baseline characteristics, cardiac troponin levels were still associated with in-hospital, short-term, and long-term mortality (p = .006, p = .007, and p = .001, respectively).

Limitations: This is a single-site retrospective study that included only patients in whom a troponin level was obtained on admission.

Conclusions: In medical intensive care unit patients, admission troponin levels are independently associated with short- and long-term mortality, even after adjustment for severity of disease.