Clinical and Metabolic Correlates of Cardiovascular Autonomic Neuropathy in Long-Standing Type 2 Diabetes: A Tertiary-Care Cross-Sectional Study from Eastern India

BACKGROUND AND OBJECTIVES: Cardiovascular autonomic neuropathy (CAN) is a serious and underdiagnosed complication of long-standing type 2 diabetes mellitus, associated with increased cardiovascular morbidity and mortality. Data from Indian populations evaluating the relationship between somatic and autonomic neuropathy remain limited. METHODS: In this cross-sectional study, 98 patients with long-standing type 2 diabetes were evaluated at a tertiary-care center in Eastern India. Somatic neuropathy was assessed clinically and electrophysiologically, while autonomic function was evaluated using standard cardiovascular autonomic reflex tests and galvanic skin response (GSR). CAN was staged as possible, definite, or advanced. Clinical and metabolic correlates were analyzed, and multivariable logistic regression was used to identify factors independently associated with CAN. RESULTS: Distal symmetric polyneuropathy was present in 44.9% of patients, and any peripheral neuropathy was present in 59.2%. CAN was highly prevalent, with definite and advanced CAN observed in 28.6% and 46.9%, respectively. Abnormal GSR was noted in 42.9%, and overall diabetic autonomic involvement (defined as the presence of CAN and/or isolated sudomotor dysfunction) was present in 92.9%. Increasing CAN severity was associated with higher hemoglobin A1c (HbA1c) ( P = 0.0055), fasting blood glucose ( P = 0.0083), and age ( P = 0.0027), while duration showed a borderline association ( P = 0.0548). HbA1c was the only variable independently associated with CAN after multivariable adjustment (adjusted odds ratio ≈ 2.10 per 1% increase). The sustained handgrip test did not demonstrate a significant association with the presence of CAN (χ², P = 0.712), indicating limited discriminatory ability in this cohort. CONCLUSIONS: Autonomic neuropathy, particularly CAN, was highly prevalent in this cohort of patients with long-standing type 2 diabetes. Poorer glycemic control, reflected by higher HbA1c, showed the strongest independent association with CAN. Comprehensive autonomic assessment should be considered even in the absence of overt somatic neuropathy.