Circulating cardiac biomarkers improve risk stratification for incident cardiovascular disease in community dwelling populations.

BACKGROUND: Plasma cardiac markers may assist in prediction of incident cardiovascular disease. METHODS: The incremental value of cardiac Troponins (T and I) and NT-proBNP added to risk factors in the PREDICT score for incident cardiovascular disease (CVD) in primary care, was assessed in 4102 asymptomatic participants in a randomised controlled trial of Vitamin D (ViDA). Findings were corroborated in 2528 participants in a separate community-based observational registry of CVD-free volunteers (HVOLS). FINDINGS: Hazard ratios for first cardiovascular events adjusted for PREDICT risk factors, comparing fifth to first quintiles of marker plasma concentrations, were 2.57 (95% CI 1.47-4.49); 3.01 (1.66-5.48) and 3.38 (2.04-5.60) for hs-cTnI, hs-cTnT and NT-proBNP respectively. The C statistic for discrimination of the primary endpoint increased from 0.755 to 0.771 (+0.016, p = 0.01). Cardiac marker data correctly reclassified risk upwards in 6.7% of patients and downwards in 3.3%. These findings were corroborated by results from HVOLS. INTERPRETATION: Increments in plasma cardiac biomarkers robustly and reproducibly predicted increased hazard of incident CVD, independent of established risk factors, in two community-dwelling populations. Cardiac markers may augment risk assessment for onset of CVD in primary care. FUNDING: ViDA was funded by the Health Research Council of New Zealand (grant 10/400) and the Accident Compensation Corporation. HVOLS was funded by the Health Research Council of NZ Programme Grants (grants 02/152 and 08/070) and by grants from the Heart Foundation of NZ and the Christchurch Heart Institute Trust. Roche Diagnostics provided in-kind support for NT-proBNP and hs-cTnT assays and Abbott Laboratories for hs-cTnI assays.