Coronary Artery Disease Events and Carotid Intima-Media Thickness in Type 1 Diabetes in the DCCT/EDIC Cohort

BACKGROUND: Carotid artery intima-media thickness (IMT) is associated with the risk of subsequent cardiovascular events in the general population. This association has not been established in type 1 diabetes. METHODS AND RESULTS: We studied if carotid IMT is associated with the risk of a first coronary artery disease event in participants with type 1 diabetes in the EDIC (Epidemiology of Diabetes Interventions and Complications) study, the long-term observational follow-up of the DCCT (Diabetes Control and Complications Trial). Between 1994 and 1996, common carotid artery and internal carotid artery IMT were measured with high-resolution ultrasound in 1309 study participants with a mean age of 35 years and diabetes duration of 13.8 years; 52% were men. Cox proportional hazards models evaluated the association of standardized common carotid artery IMT and internal carotid artery IMT with subsequent cardiovascular events over the next 17 years. Models were adjusted for age, sex, mean hemoglobin A1c levels, and traditional cardiovascular risk factors. Associations of common carotid artery IMT with subsequent CAD were significant after adjustment for imaging device, sex, and age (hazard ratio [HR], 1.23 per 0.09 mm [95% CI, [1.04-1.45]; P=0.0141), but did not remain significant after further adjustment for traditional risk factors and hemoglobin A1c (HR, 1.14 per 0.09 mm [95% CI, 0.97-1.33]; P=0.1206). No significant associations with subsequent coronary artery disease events were seen for internal carotid artery IMT. CONCLUSIONS: In the DCCT/EDIC cohort with type 1 diabetes, common carotid artery IMT, but not internal carotid artery IMT, is weakly associated with subsequent coronary artery events, an association eliminated after adjusting for coexistent traditional cardiovascular risk factors.