Association between Cardiac Autonomic Neuropathy, Diabetic Retinopathy and Carotid Atherosclerosis in Patients with Type 2 Diabetes

BACKGROUND It is not clear whether microangiopathies are associated with subclinical atherosclerosis in type 2 diabetes mellitus (T2DM). We investigated the relation of cardiac autonomic neuropathy (CAN) and other microangiopathies with carotid atherosclerosis in T2DM. METHODS A total of 131 patients with T2DM were stratified by mean carotid intima-media thickness (CIMT) ≥ or <1.0 mm and the number of carotid plaques. CAN was assessed by the five standard cardiovascular reflex tests according to the Ewing's protocol. CAN was defined as the presence of at least two abnormal tests or an autonomic neuropathy points ≥2. Diabetic microangiopathies were assessed. RESULTS Patients with CAN comprised 77% of the group with mean CIMT ≥1.0 mm, while they were 29% of the group with CIMT <1.0 mm (P=0.016). Patients with diabetic retinopathy (DR) comprised 68% of the group with CIMT ≥1.0 mm, while they were 28% of the group without CIMT thickening (P=0.003). Patients with CAN comprised 51% of the group with ≥2 carotid plaques, while they were 23% of the group with ≤1 carotid plaque (P=0.014). In multivariable adjusted logistic regression analysis, the patients who presented with CAN showed an odds ratio [OR] of 8.6 (95% confidence interval [CI], 1.6 to 44.8) for CIMT thickening and an OR of 2.9 (95% CI, 1.1 to 7.5) for carotid plaques. Furthermore, patients with DR were 3.8 times (95% CI, 1.4 to 10.2) more likely to have CIMT thickening. CONCLUSION These results suggest that CAN is associated with carotid atherosclerosis, represented as CIMT and plaques, independent of the traditional cardiovascular risk factors in T2DM. CAN or DR may be a determinant of subclinical atherosclerosis in T2DM.