A modified Canadian Syncope Risk Score for emergency department use

Syncope is a frequent presentation in the emergency department (ED) and carries a heterogeneous risk of adverse outcomes, making early stratification challenging. The Canadian Syncope Risk Score (CSRS) is among the most validated prognostic tools; however, its inclusion of the "ED diagnosis" variable may hinder real-time applicability. We aimed to evaluate a modified version of the CSRS, excluding this variable (CSRS-ED), in predicting 30-day serious outcomes. We conducted a retrospective, single-center study including 935 consecutive patients presenting with syncope to the ED of Santa Croce e Carle Hospital (Cuneo, Italy) between January 2021 and December 2024. The primary endpoint was a composite of arrhythmic and non-arrhythmic serious conditions and all-cause mortality within 30 days, in accordance with prior CSRS derivation and validation studies. CSRS-ED performance was assessed through discrimination, calibration, and diagnostic accuracy at predefined score thresholds to determine sensitivity, specificity, and predictive values. Comparisons were made with SFSR, EGSYS and OESIL scores. Overall, 127 patients (13.6%) experienced adverse outcomes, with 1.3% 30-day mortality. The CSRS-ED showed excellent discrimination (AUROC 0.87, 95% CI 0.84-0.90). At a threshold of ≥ 0, sensitivity was 0.97 with a negative predictive value of 0.99 and a negative likelihood ratio of 0.06. Calibration analysis revealed no significant miscalibration. In conclusion, the CSRS-ED maintains strong prognostic accuracy without requiring an adjudicated ED diagnosis, supporting its potential as a practical tool for early risk stratification and safe discharge decisions in ED patients presenting with syncope.