Clinical scoring systems for the risk of cardiovascular autonomic neuropathy in type 1 and type 2 diabetes: a simple tool

This study was aimed at developing a clinical risk score for cardiovascular autonomic neuropathy (CAN) for type 1 and type 2 diabetes. In a retrospective cross-sectional one-centre study in an unselected population, 115 participants with type 1 diabetes (age 41.1 ± 12.2 years) and 161 with type 2 diabetes (age 63.1 ± 8.9 years), well-characterized for clinical variables, underwent standard cardiovascular reflex tests (CARTs). Strength of associations of confirmed CAN (based on 2 abnormal CARTs) with clinical variables was used to build a CAN risk score. CAN risk score was based on resting heart rate, HbA1c, retinopathy, nephropathy, cardiovascular disease in both type 1 and type 2 diabetes, and on HDL cholesterol, systolic blood pressure, and smoking in type 1 diabetes or insulin treatment and physical activity in type 2 diabetes (range 0-10). In type 1 diabetes, CAN risk score showed an area under the ROC curve (AUC) of 0.890 ± 0.034, and at cut-off of 4 sensitivity of 88%, specificity of 74.4%, and negative predictive value (NPV) of 95.7% for confirmed CAN. In type 2 diabetes, CAN risk score showed an AUC of 0.830 ± 0.051 and at the cut-off of 4 sensitivity and specificity of 78.6% and 73.5%, respectively, and NPV of 97.3% for confirmed CAN. These newly developed CAN risk scores are accessible in clinical practice and, if confirmed in a validation study, they might identify asymptomatic individuals with diabetes at greater risk of CAN to be referred to CARTs, thus limiting the burden of a universal screening.