Evaluation of coronary plaque burden in type 2 diabetes: insights from a propensity-matched CCTA study

Background Coronary Computed Tomography Angiography (CCTA) is the first-line diagnostic tool for suspected stable Coronary Artery Disease (CAD) to rule out obstructive CAD and is recommended for risk stratification. Both obstructive CAD and total plaque burden on CCTA predict cardiovascular (CV) risk. Prior studies demonstrated that type 2 diabetes (T2D) patients exhibit greater plaque burden and higher CV event risk. Purpose This study evaluates whether T2D patients undergoing CCTA for stable CAD symptoms, when matched for traditional cardiovascular risk factors, have a higher prevalence of CAD and greater atherosclerotic plaque burden. Methods A total of 568 patients were included: 284 T2D patients were 1:1 propensity-matched to 284 non-T2D patients based on age, sex, and CV risk factors. All underwent diagnostic CCTA between January 2022 and November 2023. CCTA parameters included CAD-Reporting and Data System (RADS) classification, segment involvement score (SIS), coronary artery calcium (CAC) score, and plaque composition. SIS was defined as the number of segments with at least mild plaque. Coronary segmentation followed the 16-segment model (SCCT). Plaque burden was classified as P1 (mild), P2 (moderate), P3 (severe), and P4 (extensive) per CAD-RADS 2.0, based on SIS, CAC score, and the number and severity of affected vessels. Results The mean age was 60.8 ± 9.97 years (T2D) vs. 61.2 ± 9.80 years (non-T2D), with similar gender distribution (48.6% vs. 48.9% female). BMI was significantly higher in T2D patients (29.2 vs. 26.5, p < 0.05). Smoking was less frequent in T2D patients (56.0% vs. 60.9%, p = 0.03). Other CV risk factors were similar. T2D patients were more likely to use antiplatelet and lipid-lowering agents. CAD prevalence was higher in T2D patients (83.1% vs. 76.4%, p < 0.05), while obstructive CAD was not significantly higher in T2D (33.5% vs. 27.5%, p = 0.13). No significant differences were observed in 1-, 2-, or 3-vessel disease. The SIS was significantly higher in T2D patients (3.85 vs. 3.37, p = 0.03). CAC scores were higher in T2D patients (median 60 [6–369] vs. 31 [0–224]), though not statistically significant. For plaque burden classification, P2 (moderate plaque burden) was more common in non-T2D patients (23.6% vs. 15.5%, p = 0.02), while P4 (extensive plaque burden) was significantly higher in T2D patients (21.1% vs. 14.1%, p = 0.03). Conclusion When matched for cardiovascular risk factors, T2D patients more frequently exhibited CAD on CCTA, with higher SIS scores and a greater prevalence of extensive plaque burden (P4 classification). Despite greater use of preventive medication and a lower smoking prevalence in the T2D group, plaque burden remained higher in these patients. These findings emphasize the need for improved risk stratification and preventive strategies in individuals with T2D.