Long-term Predictions of Incident Coronary Artery Calcium to 85 Years of Age for Asymptomatic Individuals with and without Type 2 Diabetes

<b>Objective</b> <p>To examine the utility of repeated computed tomography (CT) coronary artery calcium (CAC) testing, we assessed risks of detectable CAC and its cardiovascular consequences in individuals with and without type 2 diabetes from ages 45 to 85 years.</p> <p><b>Research Design and Methods</b></p> <p>We included 5836 individuals (618 with type 2 diabetes, 2972 without baseline CAC) from the Multi-Ethnic Study of Atherosclerosis. Logistic and Cox regression evaluated the impact of type 2 diabetes, diabetes treatment duration and other predictors on prevalent and incident CAC. We used time-dependent Cox modeling of follow-up data (median 15.9 years) for two repeat CT exams and cardiovascular events to assess the association of CAC at follow-up CT with cardiovascular events.</p> <p><b>Results</b></p> <p>For 45-year-olds with type 2 diabetes, the likelihood of CAC at baseline was 23% versus 17% for those without. Median age at incident CAC was 52.2 versus 62.3 years for those with and without diabetes. Each 5 years of diabetes treatment increased the odds and hazard rate of CAC by 19% (95% confidence interval [CI] 8-33%) and 22% (95% CI 6-41%). Male gender, white ethnicity/race, hypertension, hypercholesterolemia, obesity, and low serum creatinine also increased CAC. CAC at follow-up CT independently increased coronary heart disease rates. </p> <p><b>Conclusions </b></p> <p>We estimated cumulative CAC incidence to age 85. Patients with type 2 diabetes develop CAC at a younger age than those without diabetes. Because incident CAC is associated with increased coronary heart disease risk, the value of periodic CAC-based risk assessment in type 2 diabetes should be evaluated.</p>