Abstract 15200: Improvement in Discrimination and Risk Reclassification in Asymptomatic Individuals with Diabetes by Coronary Computed Tomographic Angiography
Introduction: Asymptomatic diabetics have heightened risk for coronary artery disease (CAD) events, and coronary artery calcium scoring (CACS) has been proposed to improve risk stratification. Whether coronary computed tomography angiography (CCTA) augments discrimination and reclassification beyond clinical risk assessment and CACS remains unexplored.
Methods: From a prospective 12-center registry of 24,775 individuals undergoing CCTA, we identified 400 asymptomatic diabetics without known CAD for whom risk factors, CACS, and adverse events were available. CCTAs were graded for maximal stenosis severity (0%, 1-49%, 50-69%, and >70%). We assessed adverse events (all-cause mortality, myocardial infarction [MI], late revascularization ≥90 days [REV]), and evaluated CACS and CCTA for risk assessment, discrimination and reclassification.
Results: Mean age was 60.8±9.8 years; 62.6% were male. At a mean follow-up 2.3±1.1 years, 33 events occurred (13 deaths, 8 MI, 12 REV). On univariate analysis, increased maximal stenosis severity was associated with greater adverse events [hazards ratio (HR) 2.35 per +grade, 95% confidence interval (CI) 1.68-3.28, p<0.001). After adjustment for CAD risk factors and CACS, maximal stenosis severity was independently and positively associated with adverse events (HR 1.80 per +grade, 95% CI 1.18-2.75, p=0.006). CACS improved discrimination beyond clinical risk factors (C-index 0.74 vs. 0.64), and CCTA further improved discrimination (C-index 0.78)[Figure 1]. Addition of CCTA stenosis severity to CAD risk factors and CACS also improved risk reclassification (integrated discrimination improvement=0.19, p=0.01).
Conclusion: In asymptomatic individuals with diabetes, maximal stenosis severity by CCTA is associated with increased risk of adverse events, and improves discriminatory ability and risk reclassification above and beyond CAD risk factors and CACS.Figure 1. Receiver-Operator Curve for Adverse Events
- © 2011 by American Heart Association, Inc.