Association between Cardiac Autonomic Neuropathy and Homocysteine Level in Patients with Type 2 Diabetes Mellitus

Abstract

Introduction: Cardiac autonomic neuropathy is an important cause of increased morbidity and mortality in patients with diabetes mellitus. The aim of this study was to investigate the association between plasma homocysteine level and cardiac autonomic neuropathy assessed using the abnormal heart rate recovery index in patients with type 2 diabetes mellitus. Patients and Methods: Thirty-five patients with type 2 diabetes mellitus who underwent an exercise stress test were included in the study. Abnormal heart rate recovery index was defined as ≤ 21 beat/min, which indicated cardiac autonomic neuropathy. Results: Patients with type 2 diabetes mellitus were divided into two groups, that is, patients with a heart rate recovery index of > 21 beat/min and those with a heart rate recovery index of ≤ 21 beat/min. Clinical variables, laboratory variables and risk factors, such as age, hypertension, hyperlipidemia and smoking, were not different between the groups. However, the homocysteine level and duration of type 2 diabetes mellitus were significantly higher in patients with ≤ 21 beat/min than in those with > 21 beat/min (17.94 ± 5.91 umol/L vs 13.27 ± 2.75 umol/L, p= 0.009 and 10.06 ± 6.20 umol/L vs 6.21 ± 4.87 umol/L, p= 0.048, respectively). The homocysteine level was independently associated with the abnormal heart rate recovery index [odds ratio, 1.319 (95% CI, 1.011-1.721); p= 0.041] The homocysteine level was negatively correlated with the heart rate recovery index (r= -0.382, p= 0.024). The homocysteine cut-off value, indicating an abnormal heart rate recovery, was ≥ 15.02 umol/L, with 75% sensitivity and 63.2% specificity. Conclusion: There was an independent association with a negative correlation between the plasma homocysteine level and abnormal heart rate recovery index in patients with type 2 diabetes mellitus.