Computed Tomography Angiography Images of Coronary Artery Stenosis Provide a Better Prediction of Risk Than Traditional Risk Factors in Asymptomatic Individuals With Type 2 Diabetes: A Long-term Study of Clinical Outcomes.

Abstract

We investigated the efficacy of coronary computed tomography angiography (CCTA) in predicting the long-term risks in asymptomatic patients with type 2 diabetes and compared it with traditional risk factors. We analyzed 933 patients with asymptomatic type 2 diabetes who underwent CCTA. Stenosis was considered obstructive (≥50%) in each coronary artery segment using CCTA. The extent and severity scores for coronary artery disease (CAD) were evaluated. The primary end point was major adverse cardiovascular events (MACE), including all-cause mortality, nonfatal myocardial infarction, and late coronary revascularization during a mean follow-up period of 5.5 ± 2.1 years. Ninety-four patients with MACE exhibited obstructive CAD with a greater extent and higher severity scores (<i>P</i> < 0.001 for all). After adjusting for confounding risk factors, obstructive CAD remained an independent predictor of MACE (hazard ratio 3.11 [95% CI 2.00-4.86]; <i>P</i> < 0.001]). The performance of a risk prediction model based on C-statistics was significantly improved (C-index 0.788 [95% CI 0.747-0.829]; <i>P</i> = 0.0349) upon the addition of a finding of obstructive CAD using CCTA to traditional risk factors, including age, male, hypertension, hyperlipidemia, smoking, estimated glomerular filtration rate, and HbA_1c. Both integrated discrimination improvement (IDI) and net reclassification improvement (NRI) analyses further supported this finding (IDI 0.046 [95% CI 0.020-0.072], <i>P</i> < 0.001, and NRI 0.55 [95% CI 0.343-0.757], <i>P</i> < 0.001). In contrast, the risk prediction power of the coronary artery calcium score remained unimproved (C-index 0.740, <i>P</i> = 0.547). Based on our data, the addition of CCTA-detected obstructive CAD to models that include traditional risk factors improves the predictions of MACE in asymptomatic patients with type 2 diabetes.