The risk of death or recurrent
myocardial infarction (MI) in patients with
chest pain and baseline isolated
troponin elevation is unclear. To determine the early and short-term risk of death or MI associated with isolated
troponin elevation across a spectrum of
chest pain syndromes, we used baseline
creatine kinase (CK)-MB and
troponin data from the Platelet IIb/IIIa Antagonism for the Reduction of
Acute Coronary Syndrome Events in a Global Organization Network (
PARAGON) B
troponin substudy, the Global Utilization of Strategies To Open Occluded Coronary Arteries (GUSTO) IIa
troponin substudy, and the
Chest Pain Evaluation by
Creatine Kinase-MB,
Myoglobin, and
Troponin I (CHECKMATE) study. Patients were grouped into 1 of 4 categories based on marker status (
troponin-positive/CK-MB-positive,
troponin-positive/CK-MB-negative,
troponin-negative/CK-MB-positive, or
troponin-negative/CK-MB-negative). The adjusted odds of death or MI occurring at 24 hours and 30 days was assessed by baseline marker status using multivariable logistic regression, with the group negative for both markers used as the reference. Patients who were positive for both markers had the highest odds of the 24-hour and 30-day end point. The adjusted odds of the 30-day end point for patients with isolated
troponin elevation were 1.3 (95% confidence interval 0.7 to 2.3) and 4.8 (95% confidence interval 1.4 to 16.0) for high- and low-risk patients, respectively. The risk for 24-hour and 30-day death or MI with isolated positive CK-MB results was lower than with isolated positive
troponin results, and it was not significantly greater than if the 2 markers were negative. For patients with high- and low-risk
chest pain, baseline
troponin elevation without CK-MB elevation was associated with increased risk for early and short-term adverse outcomes. This suggests that these patients should be admitted to the hospital and monitored in either an
intensive care or step-down unit.