Validation of the Canadian syncope risk score in a large prospective international multicenter study

Abstract

Background Management and risk stratification of patients with syncope in the emergency department (ED) is often challenging. In an effort to support ED physicians in disposition decisions, the Canadian Syncope Risk Score (CSRS) was developed to predict 30-day serious outcomes. Methods The CSRS was developed in a Canadian multicenter study and contains nine predictors: predisposition to vasovagal syncope, heart disease, systolic pressure <90 or >180mmHg in the ED, troponin level >99th percentile, abnormal QRS axis, QRS duration >130ms, QTc interval >480ms and an ED diagnosis of vasovagal or cardiac syncope. Patients can achieve a CSRS score between −3 and +11 points. We validated the CSRS in a large prospective international multicenter study recruiting patients 40 years or older presenting to the ED with a syncopal event within the last 12 hours. Recruitment centers contained smaller provincial hospitals, as well as big University Hospitals in eight countries on three continents. Primary outcome measure were 30-day serious arrhythmic and non-arrhythmic adverse events, as defined by the authors of the original score. Results 1581 patients were eligible for this analysis. The population in this validation cohort was older (mean age 68 vs 54 years) and had a considerably higher rate of serious outcomes compared to the derivation cohort (n=186 (11.8%) vs n=147 (3.6%)). The area under the receiver operating characteristic curve (AUC) for the CSRS was 0.88 (95% confidence interval (CI) 0.86–0.91) and significantly higher compared to the validated OESIL score (AUC 0.75, 95% CI 0.71–0.78, p<0.001). Calibration curve analysis showed an underestimation of risk in patients with a low CSRS and an overestimation in patients with a high CSRS. The rate of observed serious outcomes within 30d increased from 0.8% in the very low risk group (CSRS equal to or below −2) to 48% in the (very) high risk group (CSRS equal to or above 4, Hazard ratio 79.4, 95% CI 11.1–570.9). A Kaplan-Meier plot was used to visualize rates of serious outcomes in three different risk groups (Figure). Conclusion This is the first validation of the Canadian Syncope Risk Score in a large international syncope cohort. The prognostic discrimination of the CSRS for 30-day serious outcomes was very good in our validation cohort and comparable to that of the Canadian derivation study. Despite suboptimal calibration, prognostic analysis showed a high rate of serious outcomes in the CSRS (very) high risk group and a low rate of serious outcomes in the very low risk group. Allowing the clinical judgement of the ED physician in the form of suspected syncope etiology to be a part of the score seems to largely contribute to the high performance of the CSRS. Additional validation studies might be needed to further increase the accuracy of the CSRS in different patient populations with a different incidence of outcomes in settings outside of Canada. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Swiss National Science Foundation; Swiss Heart Foundation

Assessment of Canadian Syncope Risk Score in the prediction of outcomes of patients with syncope at the Emergency Department of Suez Canal University

“…Our study showed that very high-risk cases had the highest distribution (35%), while cases with very low risk had lowest distribution (10%). Our results in line with Zimmermann et al, 2020 who found The rate of observed serious outcomes within 30 days increased from 0.8% in the very low risk group (CSRS equal to or below −2) to 48% in the (very) high risk group (CSRS equal to or above 4, Hazard ratio 79.4, 95% CI 11.1–570.9) [9] …”

“…Our results in line with Zimmermann et al, 2020 who found The rate of observed serious outcomes within 30 days increased from 0.8% in the very low risk group (CSRS equal to or below À2) to 48% in the (very) high risk group (CSRS equal to or above 4, Hazard ratio 79.4, 95% CI 11.1-570.9). [9] Table 2 Age classification of the study group (n = 60). Within the study population, the majority of patients were within age range of 40 to 50 years old.…”

“…Our results in line with Zimmermann et al, 2020 who found The rate of observed serious outcomes within 30 days increased from 0.8% in the very low risk group (CSRS equal to or below −2) to 48% in the (very) high risk group (CSRS equal to or above 4, Hazard ratio 79.4, 95% CI 11.1–570.9). [ 9 ]…”

Risk stratification tools for patients with syncope in emergency medical services and emergency departments: a scoping review

“…The study of moderate quality did not perform well in robust and well-defined outcome measurements and did not report some estimate of variance for the main results [48]. Of the cohort studies, 21 were of good quality [6,9,[28][29][30][31][32][33][35][36][37][38][39][40][41][42][43][44][45][46][47], one of moderate quality [27], and one of poor quality [34]. The research question was partially described in eight studies [29,31,33,34,37,40,41,46].…”

UpToDate®

“…Multiple risk stratification tools have been developed to avoid expensive unnecessary admissions for syncope, but none are universally accepted. The Canadian Syncope Risk Score (CSRS) has been validated in several sites across Canada and recently validated in an international, multicenter cohort that included over 2200 adults who presented to an emergency department (ED) with syncope 2. In nearly 1400 patients classified as low-risk by the CSRS, only 1 percent had a serious clinical event or required a procedure at 30 days.…”