Astrup AS et al. (2006) Cardiac autonomic neuropathy predicts cardiovascular morbidity and mortality in type 1 diabetic patients with diabetic nephropathy. Diabetes Care 29: 334–339

Cardiovascular autonomic neuropathy, a severe complication of diabetes, results from damage to autonomic nerve fibers leading to the heart. The earliest sign of this condition is a decrease in heart-rate variation (HRV) during deep breathing. Cardiovascular autonomic neuropathy is common in patients with diabetic nephropathy. Astrup et al. have investigated whether an abnormal HRV of ≤10 beats/min can be used to predict cardiovascular morbidity and mortality in patients with and without diabetic nephropathy.

This study included 197 patients with type 1 diabetes and diabetic nephropathy, and a control group of 191 age-matched and sex-matched patients with type 1 diabetes and normoalbuminuria. During a mean follow-up of 10.1 years, significantly more patients with nephropathy reached the combined primary endpoint of cardiovascular morbidity and mortality than did those with normoalbuminuria (40% vs 10%; P <0.0001). In patients with diabetic nephropathy, abnormal HRV was significantly associated with development of cardiovascular disease or death even after adjustment for confounding factors (hazard ratio 6.4, 95% CI 1.5–26.3; P = 0.010). In normoalbuminuric patients, however, abnormal HRV was not a significant predictor of the primary endpoint.

The authors conclude that HRV could be used, along with other risk factors, to identify patients with diabetic nephropathy who are at risk of cardiovascular disease and death, thereby enabling early intervention.