Validation of 2 Syncope Risk Scores and Comparison With Physician Risk Estimation.

Importance: Risk stratification is a key component of syncope management in the emergency department (ED), but objective risk-stratification tools have not been widely adopted. Objective: To externally validate 2 risk-stratification tools, the Canadian Syncope Risk Score (CSRS) and FAINT score, and compare their performance with unstructured physician-estimated risk. Design, Setting, and Participants: This prospective, observational, multicenter cohort study was conducted across the US from September 2020 to September 2024, enrolling ED patients aged 40 years or older with syncope or presyncope and no serious diagnosis during initial evaluation. Data were analyzed from September to December 2025. Exposure: Presence of syncope or presyncope. Main Outcomes and Measures: The primary outcome was a serious adverse outcome within 30 days of the ED visit. This included both cardiac and noncardiac outcomes for the CSRS and exclusively cardiac outcomes for the FAINT score. Unstructured estimates of each patient's risk for serious adverse outcome were obtained from the treating attending physician. Risk scores and physician-estimated risk were assessed using the area under the receiver operating characteristic curve (AUROC). Sensitivity and negative predictive value (NPV) were also calculated. Results: A total of 1263 patients were analyzed (median [IQR] age, 66.0 [55.0-74.0] years; 676 female [53.5%]), of whom 74 (5.9%) had a serious adverse outcome and 62 (4.9%) had a serious cardiac outcome. The CSRS AUROC for any serious outcome was 0.72 (95% CI, 0.67-0.78). A low-risk score (CSRS <0) had a sensitivity of 91.9% (95% CI, 85.7%-98.1%) and an NPV of 97.5% (95% CI, 96.4%-98.8%). The FAINT score AUROC for a serious cardiac outcome was 0.76 (95% CI, 0.71-0.81). A low-risk score (FAINT = 0) had a sensitivity of 96.7% (95% CI, 92.4%-100%) and an NPV of 98.8% (95% CI, 98.0%-99.7%). In comparison, physician-estimated risk less than 2% had a sensitivity of 87.5% (95% CI, 79.4%-95.6%) and an NPV of 97.4% (95% CI, 95.5%-98.9%) for any serious adverse outcome. Physician-estimated risk less than 2% had a sensitivity of 79.2% (95% CI, 68.3%-90.2%) and an NPV of 97.4% (95% CI, 95.9%-98.9%) for serious cardiac outcomes. The FAINT score, but not the CSRS, was more sensitive than physician-estimated risk (difference, 18.7%; 95% CI, 6.8%-30.6%; P = .002). Conclusions and Relevance: In this cohort study of 1263 patients, both the CSRS and the FAINT score identified patients at low risk for adverse outcomes, and FAINT outperformed physicians at identifying patients at low risk for serious cardiac outcomes. Further research on the effect of score implementation is required to understand its impact on patient care.