Comparative Evaluation of Baroreflex Sensitivity and Cardiovascular Autonomic Regulation in Type 2 Diabetes Mellitus and Healthy Individuals: A Cross-Sectional Study

Abstract

Type 2 Diabetes Mellitus (T2DM) may impair cardiovascular autonomic regulation, including arterial baroreflex function, cardiovagal responses and orthostatic blood-pressure control. Objective: To compare Baroreflex Sensitivity (BRS), cardiovascular autonomic reflex tests, resting hemodynamics and frequency-domain Heart Rate Variability (HRV) in individuals with T2DM and healthy non-diabetic controls. Methods: This comparative cross-sectional study included 120 adults aged 45-55 years (60 with T2DM and 60 non-diabetic controls). The assessed outcomes comprised resting, sequence-up and sequence-down BRS, baroreflex sequence count, cardiovagal and vasomotor reflex tests, resting cardiovascular indices and spectral HRV. Associations between BRS and clinical variables were examined within the diabetic group. Results: Resting BRS was lower in participants with T2DM than in controls (7.1±1.9 versus 14.2±2.8 ms/mmHg; p<0.0001). Sequence-up BRS (7.8±2.2 versus 15.8±3.1) and sequence-down BRS (6.5±1.8 versus 13.1±2.6 ms/mmHg) were similarly reduced. Deep-breathing E:I ratio, standing 30:15 ratio, Valsalva ratio and respiratory heart-rate variation were lower in T2DM, whereas postural systolic blood-pressure fall was greater (14.8±4.6 versus 4.2±2.1 mmHg). Total HRV power and high-frequency power were reduced. In T2DM, BRS correlated inversely with HbA1c (r = −0.724) and diabetes duration (r = −0.681), both p<0.0001. Conclusion: T2DM was associated with diminished baroreflex responsiveness, attenuated cardiovagal reflexes, impaired orthostatic compensation and reduced HRV. Higher HbA1c and longer diabetes duration were associated with lower BRS.