4-OR: Diabetes Duration and the Relative Importance of Cardiovascular Risk Factors in Type 1 Diabetes

Abstract

Based on a Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) report and their own findings, Pittsburgh Epidemiology of Diabetes Complications investigators concluded that the relative impact of HbA1c and kidney disease in type 1 diabetes (T1D) on cardiovascular disease (CVD) varies according to T1D duration. We investigate the relative importance of HbA1c and other CVD risk factors during ∼ 30 years of DCCT/EDIC follow-up within the primary (RET-: subjects with a mean T1D duration of 2.6 years and without retinopathy at baseline) and within the secondary DCCT cohort (RET+: subjects with a mean T1D duration of 8.6 years and with mild to moderate retinopathy at baseline). CVD included fatal/nonfatal myocardial infarction (MI) or stroke, silent MI, revascularization, confirmed angina, or congestive heart failure. Cox regression models with robust error variances were used to find the most significant CVD risk factors (p<0.05) within RET- and within RET+. The importance of risk factors was determined by evaluating the z value, a measure of association strength between risk factor and CVD. In case of hazard assumption violation, time by covariate interaction was included in model. DCCT enrolled 1441 subjects (age 13-39); 115 of 715 RET+ subjects and 69 of 726 RET- subjects had a CVD event. For RET+, the most important risk factors were baseline (B) age (z ∼4.2), time dependent (T) mean (M) systolic blood pressure (SBP) (z ∼4.0), any severe hypoglycemia (z ∼3.7), and TM HbA1c (z ∼3.2). Other significant risk factors included B autonomic neuropathy, TM insulin dose, TM LDL, T current (C) ACE inhibitor use, TC insulin regimen and B severity of retinopathy but not T1D duration. For RET-, B age, TM HbA1c, TC triglycerides and TM SBP with an increasing CVD effect over follow-up time were significant. The relative importance of CVD risk factors in a young T1D cohort varies according to microvascular complications, which correlate with T1D duration. Disclosure E.R. Fahrmann: None. H. Driscoll: None.