Lifetime Cardiovascular Disease Risk by Coronary Artery Calcium Score in Individuals With and Without Diabetes: An Analysis From the Multi-Ethnic Study of Atherosclerosis

Objective

To assess lifetime cardiovascular disease (CVD) risks by coronary artery calcium (CAC) scores in individuals with diabetes from the Multi-Ethnic Study of Atherosclerosis (MESA) and compare risks with those without diabetes.

Research Design and Methods

We developed a microsimulation model with ‘Well’, ‘Diabetes’, ‘Post CVD’, and ‘Death’ health states using multivariable time-dependent Cox regression with age as time scale. We initially used 10-year follow-up data of 6769 MESA participants including coronary heart disease (N=272), heart failure (N=201), stroke (N=186), and competing death (N=272), and assessed predictive validity at 15 years. We externally validated the model in matched National Health and Nutrition Examination Survey (NHANES) participants. Subsequently we predicted CVD risk until age 100 by diabetes, 10-year Pooled Cohort Equations risk, and CAC score categories (0, 1-100, 100+).

Results

The model showed good calibration and discriminative performance at 15 years with discrimination indices 0.71-0.78 across outcomes. In the NHANES cohort, predicted 15-year mortality risk corresponded well with Kaplan-Meier risks, especially for those with diabetes: 29.6% (95% CI 24.9-34.8) vs 32.4% (95% CI 27.2-37.2), respectively. Diabetes increased lifetime CVD risk similar to shifting one CAC category upwards (from 0 to 1-100 or from 1-100 to 100+). Patients with diabetes and zero CAC scores had lifetime CVD risks that overlapped with those without diabetes who are at low 10-year Pooled Cohort Equations risk <7.5%.

Conclusions

Patients with diabetes carry a spectrum of CVD risk. CAC scoring may improve decisions for preventive interventions for patients with diabetes by better delineating lifetime CVD risks.