Performance of the COMPASS-31 questionnaire with regard to autonomic nervous system testing results and medication use: a prospective study in a real-life setting.

The aim of this study was to investigate the performance of the Composite Autonomic System Score-31 (COMPASS-31) questionnaire in a real-life setting in consecutive patients referred to the laboratory for objective testing of the autonomic nervous system (ANS), with the hypothesis that COMPASS-31 results differ depending on medications and findings of the tilt table test results. One hundred seventy-one consecutive patients (125 females, mean age 41.5 ± 19.3) referred for testing of the ANS were enrolled. Before testing, all patients completed the recently validated Croatian version of COMPASS-31. The following data were systematically collected for all patients: age, sex, diagnoses, and medications. Results of COMPASS-31 were significantly higher in patients taking medications with a known influence on the ANS (p < 0.001). Patients with postural orthostatic tachycardia had significantly higher orthostatic intolerance and vasomotor domains of COMPASS-31 (p = 0.048 and p = 0.022, respectively). Patients with a cardiovagal score ≥ 1 had a significantly higher vasomotor domain of COMPASS-31 compared to patients with normal results of ANS tests (p = 0.030). These findings suggest the COMPASS-31 might be a valuable screening tool for autonomic dysfunctions, as it is associated with impaired ANS tests, but usage of medications that modify the ANS should always be taken into account.