title: Accuracy and quality of clinical decision rules for syncope in the emergency department: a systematic review and meta-analysis.
abstract: OBJECTIVE
  We assess the methodological quality and prognostic accuracy of clinical decision rules in emergency department (ED) syncope patients.
  
  
  METHODS
  We searched 6 electronic databases, reviewed reference lists of included studies, and contacted content experts to identify articles for review. Studies that derived or validated clinical decision rules in ED syncope patients were included. Two reviewers independently screened records for relevance, selected studies for inclusion, assessed study quality, and abstracted data. Random-effects meta-analysis was used to pool diagnostic performance estimates across studies that derived or validated the same clinical decision rule. Between-study heterogeneity was assessed with the I(2) statistic, and subgroup hypotheses were tested with a test of interaction.
  
  
  RESULTS
  We identified 18 eligible studies. Deficiencies in outcome (blinding) and interrater reliability assessment were the most common methodological weaknesses. Meta-analysis of the San Francisco Syncope Rule (sensitivity 86% [95% confidence interval {CI} 83% to 89%]; specificity 49% [95% CI 48% to 51%]) and the Osservatorio Epidemiologico sulla Sincope nel Lazio risk score (sensitivity 95% [95% CI 88% to 98%]; specificity 31% [95% CI 29% to 34%]). Subgroup analysis identified study design (prospective, diagnostic odds ratio 8.82 [95% CI 3.5 to 22] versus retrospective, diagnostic odds ratio 2.45 [95% CI 0.96 to 6.21]) and ECG determination (by evaluating physician, diagnostic odds ratio 25.5 [95% CI 4.41 to 148] versus researcher or cardiologist, diagnostic odds ratio 4 [95% CI 2.15 to 7.55]) as potential explanations for the variability in San Francisco Syncope Rule performance.
  
  
  CONCLUSIONS
  The methodological quality and prognostic accuracy of clinical decision rules for syncope are limited. Differences in study design and ECG interpretation may account for the variable prognostic performance of the San Francisco Syncope Rule when validated in different practice settings.
authors.affiliation: Department of Emergency Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA. serrano.luis@mayo.edu
authors.forename: Luis A
authors.initials: LA
authors.lastname: Serrano
authors.forename: Erik P
authors.initials: EP
authors.lastname: Hess
authors.forename: M Fernanda
authors.initials: MF
authors.lastname: Bellolio
authors.forename: Mohammed H
authors.initials: MH
authors.lastname: Murad
authors.forename: Victor M
authors.initials: VM
authors.lastname: Montori
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Erwin
authors.forename: Wyatt W
authors.initials: WW
authors.lastname: Decker
mesh_terms: D002985:Clinical Protocols / Q000592:standards; D004636:Emergency Service, Hospital / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D010043:Outcome and Process Assessment, Health Care; D017410:Practice Guidelines as Topic / Q000592:standards; D011379:Prognosis; D015203:Reproducibility of Results; D012307:Risk Factors; D013575:Syncope / Q000175:diagnosis* / Q000628:therapy