Validation of the Composite Autonomic Symptom Score 31 (COMPASS 31) for the assessment of symptoms of autonomic neuropathy in people with diabetes

Aims: Composite Autonomic Symptom Score (COMPASS) 31 is a self-assessment questionnaire on autonomic symptoms developed from the Autonomic Symptom Profile and COMPASS, including 31 items with 6 domains and a total weighted score. This clinic based study from one single secondary centre aimed to validate COMPASS 31, in its Italian version, for the diagnosis of diabetic cardiovascular autonomic neuropathy (CAN). Methods: Seventy-three participants with diabetes (age 55±14 years) fulfilled COMPASS 31 before undergoing CAN and diabetic polyneuropathy (DPN) assessment using cardiovascular reflex tests (CARTs), neuropathic symptoms and signs, and vibration and thermal thresholds. Results: COMPASS 31 total weighted score differed between participants with and without CAN (29.9±19.5 Vs. 16.1±14.7, P=0.003) and with and without DPN (28.9±19.1 Vs. 12.7±11.3, P<0.0001). It was related to CARTs score (rho=0.38, P=0.0013), and DPN symptoms (rho=0.61, P<0.0001) and signs scores (rho=0.49, P<0.0001). ROC analysis demonstrated a fair diagnostic accuracy of total score for CAN (AUC: 0.748±0.068, 95% C.I. 0.599-0.861) and DPN (AUC: 0.742±0.061, 95% C.I. 0.611-0.845). The best cut-off values were 16 for early CAN [sensitivity: 75.0%; specificity: 64.9%; positive predictive value (PPV): 37.5%; negative predictive value (NPV): 90.2%], and 17 for both confirmed CAN and DPN (sensitivity: 70.0% and 65.5%; specificity: 66.7% and 79.5%; PPV: 25.0% and 67.9%; NPV: 93.0% and 77.8%, respectively). COMPASS 31 had a good internal consistency according to Cronbach’s α coefficient of 0.73. Conclusions: COMPASS 31 can represent a valid, easy-to-use, quantitative assessment tool for autonomic symptoms in diabetic neuropathy, with a fair diagnostic accuracy for both CAN and DPN.