Cardiac autonomic neuropathy in type 1 diabetes

 

 

Abstract              Background: Cardiac Autonomic Neuropathy (CAN) is one of the major risk factors behind cardiovascular mortality among people with Type1 Diabetes. Early diagnosis of cardiac autonomic neuropathy using simple tests helps for the prevention of these complications. Ewing et al. described 5 simple tests to assess CAN. The objective of the study was to estimate the prevalence of cardiac autonomic neuropathy among 75 patients with Type1 diabetes using Ewing tests and to predict the risk factors associated with CAN. Methodology: We conducted a hospital based cross sectional study. The study included 75 patients with Type1 diabetes of more than 5 years duration. Type1 diabetes patients with age more than 18 years attending outpatient units under the department of general medicine Government medical college, Kozhikode during the study period of January 2018 to January 2019 was taken as study population. All patients were subjected to detailed history and physical examination. Ewing tests were used to detect the CAN. Tests were done using physiopac software at the physiology department of government medical college Kozhikode. Ewing Tests included Heart rate response to deep breathing, heart rate response to Valsalva maneuver (Valsalva ratio), blood pressure response to standing, diastolic blood pressure response to handgrip and heart rate response to standing (30:15ratio). Data was analysed using Microsoft excel and SPSS software. Results: The prevalence of CAN according to Ewing tests among 75 patients with Type1 DM was 60%. The heart rate response to deep breathing was abnormal among 80% of patients. Heart rate response to standing was abnormal in 44%. The prevalence of early CAN was 40% and the prevalence of severe CAN was 20%. There was significant association between cardiac autonomic neuropathy and poor glycemic control, disease duration, resting heart rate, triglyceride level and microvascular complications like retinopathy, neuropathy and nephropathy. There was no significant association between cardiac autonomic neuropathy age, sex, BMI, systolic and diastolic blood pressure. Conclusions: CAN is a serious chronic complication of diabetes and it is an independent predictor of cardiovascular mortality. Assessment of CAN using simple non-invasive tests like Ewing can be used for its early diagnosis and thereby help to reduce the adverse outcomes. The prevalence of CAN was 60% in our study. The most important risk factors for CAN identified in this study was duration of diabetes, poor glycemic control, elevated triglyceride level and resting heart rate. The microvascular complications of type1 diabetes were significantly associated with CAN. Furthermore, a good glycemic control can delay the development of CAN.

Keywords: Type 1 diabetes cardiac autonomic neuropathy; Ewings tests.