Progression of Cardiovascular Autonomic Dysfunction in Patients with Type 2 Diabetes Mellitus: a Seven-Year Follow-up Study

Abstract

Objective We investigated whether cardiovascular autonomic dysfunction was associated with glycemic control status over time in patients with Type 2 diabetes.

Research Design And Methods From 1999 to 2000, cardiovascular autonomic nerve function testing (AFT) was conducted on patients with Type 2 diabetes (n = 1,021) and followed-up in 2006 and Feb 2008. Tests for cardiovascular autonomic functions measured heart rate variability parameters (expiration-to-inspiration ratio (E/I), responses to the Valsalva maneuver and standing). AFT scores were determined from the results of the each test as follows: 0 = normal, 1 = abnormal. We began with those who had a score of zero and assessed the changes in total score along with biannual A1C levels.

Results At follow-up, the development of cardiovascular autonomic dysfunction was 34.5% (E/I 21.9%, Valsalva 77.8%, posture 58.9%; n = 783). The development of cardiovascular autonomic dysfunction was higher in older patients (P < 0.001) and those with longer duration of diabetes (P < 0.001), of hypertension (P = 0.005), of diabetic retinopathy (P < 0.001), and had higher levels of microalbuminuria (P = 0.002). Logistic regression analysis revealed that the development of cardiovascular autonomic dysfunction was strongly associated with the mean A1C level during the follow-up period (mean A1C > 9.0% vs. ≤ 7.0%, odds ratio 2.984, 95% CI 1.177–7.561; P = 0.021).

Conclusions The development of cardiovascular autonomic dysfunction was independently associated with microvascular complications and glycemic control status during this 7.5 year follow-up in patients with Type 2 diabetes.