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