Troponin and C-reactive protein have different relations to subsequent mortality and myocardial infarction after acute coronary syndrome: a GUSTO-IV substudy.

OBJECTIVES: We sought to evaluate C-reactive protein (CRP) and troponin T (TnT) as predictors of risk of the individual end points of mortality and myocardial infarction (MI) in a large cohort of patients with acute coronary syndrome (ACS).
BACKGROUND: Both CRP and TnT predict risk of future coronary events in patients with ACS. However, the relationships between the levels of the markers and the individual end points are still unclear.
METHODS: Baseline levels of CRP and TnT were determined in 7,108 patients with ACS not undergoing early revascularization in the Global Use of Strategies To Open occluded arteries trial IV (GUSTO-IV) trial and related to outcome at 30 days.
RESULTS: Quartiles of TnT related to 30-day mortality, which was 1.1%, 3.7%, 3.7%, and 7.4% (p < 0.001) and to the rate of MI: 2.5%, 6.7%, 7.2%, and 5.6% (p < 0.001). Quartiles of CRP also related to 30-day mortality, which was 2.0%, 3.3%, 3.9%, and 6.3% (p < 0.001), whereas there was no relationship to the 30-day rate of MI: 5.6%, 4.7%, 5.2%, and 5.9% (p = 0.48). On multivariable analysis, both TnT and CRP were independent predictors of mortality, but only TnT was a predictor of MI. The combination of CRP and TnT provides an even better risk stratification of mortality, with 0.3% and 9.1% death rates, respectively, when both markers are in the bottom versus top quartiles.
CONCLUSIONS: In ACS, baseline levels of TnT and CRP are independently related to 30-day mortality. Any detectable elevation of TnT, but not of CRP, is also associated with an increased risk of subsequent MI. Regarding mortality, the combination of both markers provides a better risk stratification than either one alone.