Cardiac autonomic neuropathy in type 1 and type 2 diabetes patients

Cardiac autonomic neuropathy (CAN) in diabetes is among the strongest risk markers for future global and cardiovascular mortality. The aim of this study was to analyse CAN prevalence and to compare the associations between CAN, the glycaemic control, cardiovascular risk factors, peripheral neuropathy, retinopathy and macroangiopathy in patients with type 1 (T1DM) and type 2 diabetes mellitus (T2DM).

One hundred ninety-five diabetic patients were included in this study. All patients were evaluated for detection of CAN (with standardised cardiovascular reflex tests), diabetes-related microvascular complications (polyneuropathy, retinopathy), common carotid artery intima-media thickness (IMT) and ankle-brachial index (ABI).

The prevalence of CAN was 39.1% in T2DM and 61.8% in T1DM patients. Multivariate logistic regression analysis demonstrated that in T2DM, the odds [OR (95% confidence intervals)] of CAN increased with diabetes duration [1.67(1.42-1.92)], HbA1c [1.74(1.34-2.27)], cholesterol [1.01(1.00-1.01)], triglycerides [1.01(0.99-1.00)], smoking [2.35(1.23-4.49)], systolic blood pressure [1.01(1.00-1.03)], BMI [1.16(1.08-1.24)], glomerular filtration rate [0.91(0.88-0.93)], peripheral neuropathy [25.94(11.04-44.25)], retinopathy [13.13(3.03-84.73)] and IMT [10.12 (7.21-15.32)]. In T1DM, the odds of CAN increased with diabetes duration [1.62(1.13-2.31)], HbA1c [4.49(1.27-15.9)], age of patients [1.14(1.03-1.27)], glomerular filtration rate [0.94(0.89-0.99)], peripheral neuropathy [31.6(4.5-45.8)] and IMT [5.5(2.3-8.3)].

This study indicated that CAN is a more frequent complication in T1DM. Apart from glycaemic control, the existence of CAN is associated with potentially modifiable cardiovascular risk only in T2DM patients. The presence of other micro- and macrovascular complications increases the probability of having CAN in both types of DM (but more pronounced in T2DM).