Autonomic Imbalance in Coexistent Diabetes and Hypertension: A Clinical Evaluation Using Noninvasive Testing

These changes are associated with increased risks of silent ischemia, orthostatic hypotension, exercise intolerance, and sudden cardiac death. 5,6iven the importance of early identification and risk stratification, autonomic function testing offers a valuable tool for clinical assessment.Among the battery of available tests, the heart rate response to deep breathing (HRDB) and the isometric handgrip test have been widely validated and are notable for their simplicity, IntroductIonDiabetes mellitus and hypertension are two of the most prevalent and impactful chronic noncommunicable diseases globally, each contributing independently and synergistically to the rising burden of cardiovascular morbidity and mortality.Epidemiological data indicate a frequent coexistence of these conditions, with hypertension being present in up to 70% of individuals with type 2 diabetes mellitus. 1The coexistence of these diseases results in a multiplicative increase in the risk of adverse cardiovascular events such as myocardial infarction, stroke, and heart failure.Both diseases share overlapping pathophysiological mechanisms, including endothelial dysfunction, oxidative stress, low-grade inflammation, and altered neurohormonal regulation. 2 Autonomic nervous system (ANS) dysfunction is a critical yet often underrecognized complication of both diabetes and hypertension.The ANS regulates cardiovascular homeostasis via heart rate, vascular tone, and blood pressure variability. 3In diabetes, chronic hyperglycemia induces autonomic neuropathy through mechanisms such as sorbitol accumulation, advanced glycation end-products (AGEs), mitochondrial dysfunction, and ischemia of the vasa nervorum.Hypertension contributes via baroreceptor desensitization, arterial stiffening, and neurohumoral imbalance. 4hen coexisting, these conditions synergistically accelerate autonomic decline, leading to reduced heart rate variability, impaired baroreflex sensitivity, and blunted autonomic responses.