Autonomic Neuropathy in Ambulatory Type 2 Diabetes Mellitus Patients: A Single-arm Prospective, Observational Study

Introduction: Diabetic autonomic neuropathy (DAN), a serious complication of diabetes, is a significant contributor to increased morbidity and mortality. Although DAN often coexists with different peripheral neuropathies and other complications, it may also present in isolation. The present study aimed to understand the DAN status of a cohort of ambulatory type 2 diabetics in a tertiary care setting. Methods: A single-arm prospective observational study was carried out, where enrolled patients were interviewed for basic demographics and comorbidities, screened for symptoms of autonomic dysregulation, and other risk factors such as smoking and alcoholism. Based on the presence of overt symptoms, they were divided into two groups with or without any overt symptoms of autonomic neuropathy. Both groups were subjected to a battery of autonomic neuropathy tests, and their DAN status was characterized based on the observed scores. Results: The overall prevalence of DAN, as observed in our study, was 36%. Of 108 patients, 97 presented with one or more symptoms of autonomic dysregulation, whereas the rest, 10.1%, were without any symptoms. Among heart rate-based tests, a significant (P < 0.001) decrease followed by an increase in the Valsalva ratio was observed in 6 months and 12 months, respectively. A significant decrease (P < 0.001) in deep breathing test (E: I) values was observed in the 12(th) month. Most of the DAN patients presented with moderate autonomic dysfunction, followed by mild and severe, respectively. However, no significant change in DAN severity was noted with time. Conclusion: Using simple cardiovascular tests, DAN can be detected during the asymptomatic phase of the disease.