Effectiveness of the Composite Autonomic Symptom Score 31 Scale in Evaluating Autonomic Dysfunction in Diabetic Peripheral Neuropathy: A Comparative Study Using Autonomic Function Testing as Reference

Background: Autonomic dysfunction is a common yet underdiagnosed complication of diabetic peripheral neuropathy (DPN), contributing to increased morbidity. Early detection is critical for prompt management. The Composite Autonomic Symptom Score 31 (COMPASS-31) is a self-administered questionnaire developed to assess autonomic symptoms. However, its validity compared to standardized autonomic function testing (AFT) has not been fully established in diabetic populations. Materials and Methods: This observational cross-sectional study was conducted at AIIMS Bhopal on 72 patients with type 2 diabetes mellitus of more than 1-year duration. Each participant underwent evaluation using the COMPASS-31 questionnaire, heart rate variability (HRV) parameters, and cardiovascular reflex tests according to Ewing’s criteria. Diagnostic accuracy measures – sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) – were calculated using AFT as the reference standard. Correlation analysis was performed between COMPASS-31 scores and HRV parameters. Results: Autonomic dysfunction was identified in 72% of the study population through AFT. The COMPASS-31 scale was abnormal in 36% of cases. It showed a sensitivity of 34.61%, specificity of 60%, PPV of 69.23%, and NPV of 26.08%. Significant positive correlations were found between COMPASS-31 scores and several HRV indices ( r > 0.5, P < 0.001), indicating its potential utility in assessing autonomic symptoms. Conclusions: While the COMPASS-31 scale exhibits moderate diagnostic accuracy, it offers a feasible, noninvasive method for preliminary screening of autonomic dysfunction in DPN, particularly in settings lacking access to comprehensive autonomic testing.