Assessment of Functions of the Autonomic Nervous System in the Elderly with Different Comorbid Factors

Abstract

Background Studies in healthy elderly patients have shown the prevalence of autonomic dysfunction (AD) in the range of 20 to 30%. However, there is paucity in data pertaining to AD in the elderly in the Indian context. Objective To assess the prevalence of AD in the elderly irrespective of their comorbidity status. Methods A total of 141 elderly patients with or without comorbidities/symptoms of AD were included. Demographic and clinical details of the patients were recorded. Autonomic function tests (AFTs) such as deep breathing test, Valsalva ratio, orthostatic heart rate (OHR), isometric handgrip test, and orthostatic blood pressure were performed based on Ewing's battery of tests. The sensitivity, specificity, positive predictive value, negative predictive value, and the accuracy of AFTs were evaluated. Results Most patients (n = 85) were aged between 60 and 69 years, with a male predominance (58.87%). Hypertension and diabetes mellitus were the most common comorbidities. Postural hypotension was the most common symptom of AD. With advancing age, symptoms of AD manifested significantly more. Overall, 73.8% of patients had AD, of whom 45.4% had early AD. Number of AD symptoms, glycated hemoglobin (HbA1c) level, and comorbid factors (diabetes and hypertension) were significantly associated with the results of AFTs (p < 0.05). AFTs were highly significant with respect to the results obtained (p < 0.001). Deep breathing test, abnormal in majority of study patients, has a sensitivity of 93.3% and OHR has a specificity of 81.1% to determine AD. Conclusion The study concludes that age itself is an independent predictor of AD, which increases in severity if associated with comorbidities.