Benefit of hospital admission for detecting serious adverse events among emergency department patients with syncope: a propensity-score-matched analysis of a multicentre prospective cohort.

BACKGROUND: The benefit of hospital admission after emergency department evaluation for syncope is unclear. We sought to determine the association between hospital admission and detection of serious adverse events, and whether this varied according to the Canadian Syncope Risk Score (CSRS). METHODS: We conducted a secondary analysis of a multicentre prospective cohort of patients assessed in the emergency department for syncope. We compared patients admitted to hospital and discharged patients, using propensity scores to match 1:1 for risk of a serious adverse event. The primary outcome was detection of a serious adverse event in hospital for admitted patients or within 30 days after emergency department disposition for discharged patients. RESULTS: We included 8183 patients, of whom 743 (9.1%) were admitted; 658/743 (88.6%) were matched. Admitted patients had higher odds of detection of a serious adverse event (odds ratio [OR] 5.0, 95% confidence interval [CI] 3.3-7.4), nonfatal arrhythmia (OR 5.1, 95% CI 2.9-8.8) and nonarrhythmic serious adverse event (OR 6.3, 95% CI 2.9-13.5). There were no significant differences between the 2 groups in death (OR 1.0, 95% CI 0.4-2.7) or detection of ventricular arrhythmia (OR 2.0, 95% CI 0.7-6.0). Differences between admitted and discharged patients in detection of serious adverse events were greater for those with a CSRS indicating medium to high risk (p = 0.04). INTERPRETATION: Patients with syncope were more likely to have serious adverse events identified within 30 days if they were admitted to hospital rather than discharged from the emergency department. However, the benefit of hospital admission is low for patients at low risk of a serious adverse event.