Diagnosis, staging, and associated conditions of cardiovascular autonomic neuropathy in Libyan patients with diabetes

Background: Cardiovascular autonomic neuropathy (CAN) can affect daily activities and patients' quality of life and evoke potentially life-threatening outcomes in diabetes mellitus (DM). Objectives: We aimed to identify and characterize CAN and associated disorders in Libyan patients with DM at National Diabetes Hospital. Patients and Methods: Ninety-nine patients with DM seen in the outpatient clinics from October 2017 to April 2018 at National Diabetes Hospital were prospectively evaluated. Assessments for CAN were made by clinical symptoms and signs, cardiovascular autonomic reflex tests, and echocardiogram. Patients with potentially confounding concomitant medical conditions were excluded. CAN is defined as possible (one abnormal cardiovagal test), confirmed (two abnormal such tests), and severe (with concomitant orthostatic hypotension and heart rate abnormality). Results: Sixty-two percent of the studied patients (mean age: 52 ± 1.5 years, 53% – female) with DM had CAN. CAN diagnosis was possible in 18% of these patients, confirmed in 6%, and severe in 38%. The presence of severe CAN was associated with hypoglycemic unawareness (P = 0.01), dyslipidemia (P = 0.012), and microvascular diabetic complications (P = 0.04). Conclusions: In this cohort of relatively old and high-risk cardiovascular disease, patients with diabetes, uncontrolled blood pressure, associated dyslipidemia, presence of microvascular complication of diabetes, and history of hypoglycemic unawareness were strongly associated with a severe form of cardiac autonomic neuropathy with potentially serious clinical consequences. Larger and more detailed studies are needed to elucidate further the complex association between hypoglycemia and cardiac autonomic dysfunction.