Glycemia and cardiovascular disease in type 1 diabetes mellitus

To evaluate the role of glycemic control in the development of cardiovascular disease (CVD) in type 1 diabetes mellitus (DM).

We review the literature regarding coronary atherosclerosis, coronary artery calcification, and the epidemiologic studies related to the role of glycemia and the classic risk factors for coronary artery disease (CAD) in type 1 DM.

Four prospective studies (Wisconsin Epidemiologic Study of Diabetic Retinopathy, EURODIAB, Steno Diabetes Center Study of Adults With Type 1 DM, and Pittsburgh Epidemiology of Diabetes Complications study) do not show that glycemic control predicts CAD occurrence. Findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study show that compared with conventional insulin therapy, intensive insulin therapy reduces CVD among patients with type 1 DM and is associated with lower prevalence of coronary artery calcification. The discrepancies between the findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study and the Pittsburgh Epidemiology of Diabetes Complication study are likely due to differences between the study populations and the lower prevalence of renal disease in the former study. Besides duration of DM and albuminuria/overt nephropathy, insulin resistance is a major determinant of CAD associated with type 1 DM.

Discrepant study results regarding the relationship between glycemia and CAD/coronary artery calcification may be related to the prevalence of renal disease and the presence of the metabolic syndrome. Published data suggest that addressing traditional risk factors including albuminuria, the metabolic syndrome, and inflammatory markers is better for preventing and treating CAD than focusing exclusively on glycemic control, which is still necessary for preventing microvascular complications. Furthermore, there is a synergistic effect of glycemic control and albuminuria on the development of CVD.