Background: Several biomarkers have been shown to improve risk stratification in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS); however, they have not been integrated into risk prediction tools.
Methods: C-reactive-protein, N-terminal-pro-brain natriuretic peptide (NT-proBNP), and haemoglobin A1C were measured in 6447 patients with NSTEACS who were enrolled in the Clopidogrel in Unstable Angina to Prevent Recurrent Events trial. A risk score to predict cardiovascular (CV) death, myocardial infarction (MI), or stroke at 1 year was developed by incorporating biomarkers that were independently predictive of events with traditional variables, electrocardiogram, and troponin-T. Model discrimination was evaluated using c-statistic, integrated discrimination improvement, and net reclassification index, and validated using bootstrap methods.
Results: During 1 year of follow-up, 686 patients experienced a CV event. Each biomarker predicted CV death, MI, or stroke; however, only NT-proBNP and haemoglobin A1C improved model discrimination, increasing the c-statistic (0.66-0.71), integrated discrimination improvement to 3.4%, and net reclassification index to 17.5% (P < 0.0001 for all measures). A risk score ranging from 0 to 20 points including variables for age, prior MI/stroke, sex, ST-segment deviation, troponin-T, NT-proBNP, and haemoglobin A1C classified individuals into low-, intermediate-, and high-risk groups with rates of CV death, MI, stroke of 3.7%, 9.1%, 17.8%, respectively. The absolute benefit of dual antiplatelet therapy vs aspirin alone was 1.0%, 4.7%, and 3.0% in low-, intermediate-, and high-risk groups, respectively.
Conclusions: The addition of NT-proBNP and haemoglobin A1C to 5 standard variables creates a 7-variable risk score that improves prediction of CV events at 1 year and aids in risk-based selection of patients with NSTEACS for dual antiplatelet therapy.
Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.