Decreased -Cell Function is Associated with Cardiovascular Autonomic Neuropathy in Chinese Patients Newly Diagnosed with Type 2 Diabetes

The influence of -cell function on cardiovascular autonomic neuropathy (CAN), an important diabetes-related complication, is still unclear. In this study, we aimed to investigate the association between residual -cell function and CAN in patients newly diagnosed with type 2 diabetes. We enrolled 90 newly-diagnosed type 2 diabetic patients and 37 participants with normal glucose tolerance as controls. The patients were divided into a CAN+ group (diabetic patients with CAN, n=20) and a CAN- group (diabetic patients without CAN, n=70) according to the standard Ewing battery of tests. Fasting and postprandial plasma glucose, insulin, and C-peptide were measured. Homeostasis model assessment-beta cells (HOMA-B) and HOMA-insulin resistance (IR) were calculated. The prevalence of CAN in this population was 22.2%. Compared with the CAN- group, the CAN+ group had significantly lower fasting plasma insulin (6.60 +/- 4.39 vs 10.45 +/- 7.82 /L, P=0.029), fasting C-peptide (0.51 +/- 0.20 vs 0.82 +/- 0.51 nmol/L, P=0.004), and HOMA-B (21.44 +/- 17.06 vs 44.17 +/- 38.49, P=0.002). Fasting C-peptide was correlated with the Valsalva ratio (r=0.24, P=0.043) and the 30:15 test (r=0.26, P=0.023). Further analysis showed that fasting C-peptide (OR: 0.041, 95% CI 0.003-0.501, P=0.012) and HOMA-B (OR: 0.965, 95% CI 0.934-0.996, P=0.028) were independently associated with cardiovascular autonomic nerve function in this population. The patients with fasting C-peptide values < 0.67 nmol/L were more likely to have CAN than those with C-peptide levels 0.67 nmol/L (OR: 6.00, 95% CI 1.815-19.830, P=0.003). A high prevalence of CAN was found in patients with newly-diagnosed type 2 diabetes. Decreased -cell function was closely associated with CAN in this population.