Progression of Cardiovascular Autonomic Neuropathy and Cardiovascular Events in Type 2 Diabetic Patients.

Diabetic autonomic neuropathy has a significantly negative impact on survival and quality of life in type 2 diabetic patients. Especially, cardiovascular autonomic neuropathy (CAN) is clinically important, because of its association with cardiovascular death. We investigated whether the progression of CAN is related to the cardiovascular events in type 2 diabetic patients. Total 683 type 2 diabetic patients, 244 males and 439 females, visited Diabetes Clinic. Autonomic function test at baseline was conducted from January 2000 to December 2000, and was followed from January 2006 to December 2006. Standard tests for CAN were composed of heart rate variability (E/I ratio, response to the Valsalva maneuver and standing). CAN score was determined by the results of each test as following: 0=normal, 1 =abnormal (total score 3). Progress was defined when the total score at follow was higher than the baseline score. Total 425 patients were evaluated after six years. Mean age and duration of diabetes were 58.1 ± 10.3, and 8.3 ± 7.0 years, respectively. Among the total number of patients, 106 patients (24.9%) were the group in progress. 53 patients (12.5%) developed cerebral infarction (CVA), and 46 patients (10.8%) experienced ischemic heart attack (CAD; angina, myocardial infarction) during the observation period. There were no differences in body mass index, postprandial hyperglycemia, and HbA1c level between two groups. Compared to group in non-progress, both CAD and CVA were developed more frequently in 'progress' group (21.7 vs. 14.7%, P<0.05). The incidence of vascular events were higher in patients with older age (P=0.008), longer diabetic duration (P=0.003), hypertension (P<0.001), and diabetic retinopathy (p=0.0013). Patients with CVA or CHD had lower HDL cholesterol level (39.1 ± 10.7 vs. 42.1 ± 10.8 mg/dl, p < 0.05), and higher fasting insulin (14.0 ± 14.2 vs. 9.6 ± 10.1 µIU/ml, p < 0.05) than patients without CVA or CHD. Logistic regression analysis revealed the progress of CAN score to be deeply related to the development of vascular event (OR 2.487, CI 1.134-5.458, P=0.023). These results suggest that cardiovascular autonomic function could predict the development of CVA or CAD, therefore, it could be a good screening method for the cardiovascular events in type 2 diabetic patients. [ABSTRACT FROM AUTHOR]