Subclinical atherosclerosis and estimated glucose disposal rate as predictors of mortality in type 1 diabetes.

PURPOSE: To investigate the usefulness of ischemic resting electrocardiogram (ECG), ankle brachial index (ABI) <0.8, ankle brachial difference (ABD) > or = 75 mm Hg (a marker of peripheral medial arterial wall calcification), and estimated glucose disposal rate (eGDR) (a marker for insulin resistance) for predicting mortality risk in the context of standard risk factors.
METHODS: Data are from participants in the Pittsburgh Epidemiology of Diabetes Complications Study of 658 subjects with childhood onset Type 1 diabetes of mean age 28 years (range 8-48) and duration of diabetes 19 years (range 7-37) at baseline. Deaths were confirmed by death certificates.
RESULTS: There were 68 deaths from all causes during 10 years follow-up. In univariate analysis, the mortality hazard ratios and 95% confidence intervals associated with ischemic ECG (6.7, 3.7-12.1), the lowest quintile of eGDR (i.e., the most insulin resistant) (6.7, 4.1-10.9), ABI <0.8 (2.5, 1.1-5.9), and ABD > or = 75 mm Hg (6.7) were only marginally less than those conveyed by pre-existing coronary artery disease (8.4, 4.7-15.2) or overt nephropathy (7.6, 4.5-12.9). Ischemic ECG and eGDR were independent mortality predictors, together with duration of diabetes, coronary artery disease, overt nephropathy, nonhigh density lipoprotein cholesterol, and smoking history. If serum creatinine was available, it entered, and glycosylated hemoglobin replaced eGDR.
CONCLUSIONS: Estimated GDR and ECG ischemia are strong predictors of mortality in type 1 diabetes and may be useful in the identification of those at risk.