Diabetes, Glucose, Insulin, and Heart Rate Variability

Abstract

OBJECTIVE—To describe the progression of autonomic impairment among individuals with diabetes and pre-diabetic metabolic impairments. RESEARCH DESIGN AND METHODS—We investigated the consequence of diabetes and pre-diabetic metabolic impairments on the 9-year change in heart rate variability (HRV) in a population-based cohort of 6,245 individuals aged 45–64 years at baseline and cross-sectional associations among 9,940 individuals. RESULTS—Diabetic subjects had a more rapid temporal decrease in HRV conditional on baseline HRV than nondiabetic subjects. Adjusted mean annual changes (95% CI) (ms/year) in the SD of all normal-to-normal R-R intervals were −0.65 (−0.69 to −0.61) for those with normal fasting glucose vs. −0.95 (−1.09 to −0.81) for diabetic subjects, in root mean square of successive differences in normal-to-normal R-R intervals −0.35 (−0.39 to −0.30) vs. −0.66 (−0.82 to −0.51), and in R-R interval 6.70 (6.37–7.04) vs. 3.89 (2.72–5.05). While we found cross-sectional associations between decreased HRV and diabetes and nondiabetic hyperinsulinemia and a weak inverse association with fasting glucose, neither impaired fasting glucose nor nondiabetic hyperinsulimenia was associated with a measurably more rapid decline in HRV than normal. CONCLUSIONS—Cardiac autonomic impairment appears to be present at early stages of diabetic metabolic impairment, and progressive worsening of autonomic cardiac function over 9 years was observed in diabetic subjects. The degree to which pre-diabetic metabolic impairments in insulin and glucose metabolism contribute to decreases in cardiac autonomic function remains to be determined.