Reduced Heart Rate Variability Predicts Progression of Coronary Artery Calcification in Adults with Type 1 Diabetes and Controls Without Diabetes

Abstract

Reduced heart rate variability (HRV) is a manifestation of cardiac autonomic neuropathy, a known complication of type 1 diabetes (T1D). We evaluated whether HRV predicted coronary artery calcium (CAC) progression. Subjects between 19 and 56 years of age with T1D or those without diabetes from the Coronary Artery Calcification in Type 1 Diabetes study underwent supine deep breathing 12-lead electrocardiograms. The SD of consecutive RR intervals was used as a measure of HRV. CAC was measured at two visits 6.0 ± 0.5 years apart. Progression of CAC was defined as an increase in square root transformed CAC volume of ≥ 2.5 mm(3), excluding patients who had cardiovascular events during follow-up. Reduced HRV was associated with older age, higher hemoglobin A1c, elevated albuminuria, CAC volume at baseline, and increased fibrinogen. Higher HRV at baseline was associated with lower likelihood CAC progression (odds ratio = 0.71, 95% confidence interval 0.56-0.90, P = 0.005), and the adjustment for known cardiovascular risk factors did not change this strong association, including adjustment for inflammatory markers. Reduced HRV predicted progression of CAC in adults with and without T1D. This association further supports the participation of autonomic neuropathy in the atherosclerosis process.