Coronary Artery Calcium Score Predicts Long-Term Cardiovascular Outcomes in Asymptomatic Patients with Type 2 Diabetes

Aims: Type 2 diabetes mellitus (T2DM) is no longer regarded as a coronary risk equivalent, and heterogeneity of cardiovascular risk exists, suggesting that further risk stratification should be mandatory. This study aimed to determine the prevalence and clinical predictors of coronary artery calcium (CAC) score, and evaluate the CAC score as a predictor of cardiovascular outcome in a large asymptomatic T2DM cohort. Methods: A total of 2,162 T2DM patients were recruited from a Diabetes Shared Care Network and the CAC score was measured. Cardiovascular outcomes were obtained for 1,928 patients after a follow-up of 8.4 years. Multiple regression analysis and Cox proportional hazard regression were applied to identify clinical predictors of CAC and calculate the incidence and hazard ratios (HRs) for all-cause mortality and cardiovascular events by CAC category. Results: Of the recruited patients, 96.8% had one or more risk factors. The distribution of CAC scores was as follows: CAC= 0 in 24.2% of the patients, 0 <CAC > 100 in 41.5%, 100 < CAC > 400 in 20.3%, CAC >400 in 14.7%. The multivariable predictor of increased CAC included age (years) (odds ratio, 1.07; 95% confidence interval, 1.06-1.08), male sex (1.82; 1.54-2.17), duration (years) of T2DM (1.07; 1.05-1.09), and multiple risk factors (1.94; 1.28-2.95). Increasing severity of CAC was associated with higher all-cause or cardiac mortality and higher incident cardiovascular events. The HRs for cardiac death or major cardiac events in CAC > 400 vs CAC= 0 were 8.67 and 10.52, respectively (p<0.001) Conclusion: CAC scoring provides better prognostication of cardiovascular outcome than traditional risk factors in asymptomatic T2DM patients, and may allow identifying a high-risk subset for enhancing primary prevention.