Relationship between cardiovascular autonomic neuropathy and coronary artery calcification in patients with type 2 diabetes

To test the hypothesis that cardiovascular autonomic neuropathy (CAN) in Type 2 diabetes is a risk factor of coronary artery calcification (CAC), in this cross-sectional study, 118 patients (60 males, 58 females) with type 2 diabetes mellitus were randomly selected from the diabetes clinic of Kyungpook National University Hospital, Daegu, Korea, between January, 2008 and September, 2008. The subjects, whose mean age was 56.9±1.1 years, were tested for CAN by Ewing's method which employs five non-invasive tests of autonomic function. The coronary calcium score (CCS) was determined by Multi Detector-row Computed Tomography (MDCT). Statistical analysis was performed by using SPSS 13.0 (SPSS, Inc., Chicago, Illinois). CAN was found in 31/118 (26.3%) patients. Compared to the patients without CAN, the patients with CAN were significantly older and had significantly higher triglyceride levels, blood pressure, pulse pressure, fasting c-peptide levels, CAN scores, and log-transformed coronary calcium scores [ln(CCS+1)]. The CAN scores correlated positively with ln(CCS+1) values (r = 0.214; P = 0.028). Multiple regression analysis using ln(CCS+1) as a dependent variable showed that CAN score (β coefficient 0.623, 95% CI 0.059~1.188, P = 0.031) associated independently with ln(CCS+1). In conclusion, CAN was associated independently with CAC, which suggests that CAN is a risk factor of coronary atherosclerosis in patients with type 2 diabetes. This may help to explain the excess cardiovascular mortality seen in diabetic patients with CAN.