Elevated cardiac troponin levels predict the risk of adverse outcome in patients with acute coronary syndromes

Background: Elevations of cardiac troponin T or I are predictive of adverse outcomes in patients with acute coronary syndromes. However, odds ratios (ORs) vary substantially between studies. This investigation refines these values by means of a meta-analysis. Methods: Twenty-one studies were suitable. ORs were calculated for short-term (30 days) and long-term (5 months to 3 years) follow-up in patients with ST-segment elevation (ST↑), in those without ST-segment elevation (no ST↑), and in patients with unstable angina. The primary end point was a composite of death or nonfatal myocardial infarction. Results: A total of 18,982 patients were included. At 30 days, the OR for death or myocardial infarction was 3.44 (95% confidence interval [Cl], 2.94-4.03; P< .00001) for patients with positive troponin. In the ST↑ group, troponin elevations carried a 2.86-fold (95% Cl, 2.35-3.47; P < .0001) higher risk during short-term follow-up, which was maintained long term. The no-ST↑ patients with troponin elevations manifested a 4.93-fold (95% Cl, 3.77-6.45; P < .0001) increase of adverse outcomes. The OR for patients with unstable angina and positive troponin was 9.39 (95% Cl, 6.46-13.67; P < .0001). For cardiac death alone, the results were similar. Conclusions: Patients with acute coronary syndromes who have troponin elevations show a substantial increase in risk during short and long-term follow-up.