Serum Cystatin C Levels are Positively Associated with Cardiovascular Autonomic Neuropathy in Patients with Type 2 Diabetes

Aims: Previous studies have reported that cystatin C is associated with degenerative disorder in the nervous system. However, the relationship between serum cystatin C concentrations and cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes is currently unknown. The aim of this study was to assess the relationships between serum cystatin C levels and CAN in patients with type 2 diabetes. Methods: A total of 357 patients with type 2 diabetes were studied in this cross-sectional study. CAN was diagnosed by a cardiovascular autonomic reflex test. According to the American Diabetes Association criteria, the degree of cardiovascular autonomic dysfunction was graded as normal, early, definite, or severe. CAN was either definite or severe in the subjects of the present study. Results: Serum cystatin C concentrations were significantly higher in patients with CAN than in those without CAN. The mean cystatin C levels differed significantly according to the degree of cardiovascular autonomic dysfunction (normal, 0.78 mg/l; early, 0.79 mg/l; definite, 0.87 mg/l; severe, 0.90 mg/l; P for trend=0.021) after adjustment for other covariates. In multivariate analysis, serum cystatin C levels were significantly associated with CAN (odds ratio [OR] of each standard deviation increase in the logarithmic value, 5.25; 95 % confidence interval [CI], 1.17-23.70, P = 0.025). Conclusions: Serum cystatin C levels are positively associated with CAN in patients with type 2 diabetes.