title: Prospective validation of the ABCD2 score for patients in the emergency department with transient ischemic attack.
abstract: BACKGROUND
  The ABCD2 score (Age, Blood pressure, Clinical features, Duration of symptoms and Diabetes) is used to identify patients having a transient ischemic attack who are at high risk for imminent stroke. However, despite its widespread implementation, the ABCD2 score has not yet been prospectively validated. We assessed the accuracy of the ABCD2 score for predicting stroke at 7 (primary outcome) and 90 days.
  
  
  METHODS
  This prospective cohort study enrolled adults from eight Canadian emergency departments who had received a diagnosis of transient ischemic attack. Physicians completed data forms with the ABCD2 score before disposition. The outcome criterion, stroke, was established by a treating neurologist or by an Adjudication Committee. We calculated the sensitivity and specificity for predicting stroke 7 and 90 days after visiting the emergency department using the original "high-risk" cutpoint of an ABCD2 score of more than 5, and the American Heart Association recommendation of a score of more than 2.
  
  
  RESULTS
  We enrolled 2056 patients (mean age 68.0 yr, 1046 (50.9%) women) who had a rate of stroke of 1.8% at 7 days and 3.2% at 90 days. An ABCD2 score of more than 5 had a sensitivity of 31.6% (95% confidence interval [CI] 19.1-47.5) for stroke at 7 days and 29.2% (95% CI 19.6-41.2) for stroke at 90 days. An ABCD2 score of more than 2 resulted in sensitivity of 94.7% (95% CI 82.7-98.5) for stroke at 7 days with a specificity of 12.5% (95% CI 11.2-14.1). The accuracy of the ABCD2 score as calculated by either the enrolling physician (area under the curve 0.56; 95% CI 0.47-0.65) or the coordinating centre (area under the curve 0.65; 95% CI 0.57-0.73) was poor.
  
  
  CONCLUSIONS
  This multicentre prospective study involving patients in emergency departments with transient ischemic attack found the ABCD2 score to be inaccurate, at any cut-point, as a predictor of imminent stroke. Furthermore, the ABCD2 score of more than 2 that is recommended by the American Heart Association is nonspecific.
authors.affiliation: Department of Emergency Medicine, University of Ottawa, Ottawa, Ont. jperry@ohri.ca
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Perry
authors.forename: Mukul
authors.initials: M
authors.lastname: Sharma
authors.forename: Marco L A
authors.initials: ML
authors.lastname: Sivilotti
authors.forename: Jane
authors.initials: J
authors.lastname: Sutherland
authors.forename: Cheryl
authors.initials: C
authors.lastname: Symington
authors.forename: Andrew
authors.initials: A
authors.lastname: Worster
authors.forename: Marcel
authors.initials: M
authors.lastname: Émond
authors.forename: Grant
authors.initials: G
authors.lastname: Stotts
authors.forename: Albert Y
authors.initials: AY
authors.lastname: Jin
authors.forename: Weislaw J
authors.initials: WJ
authors.lastname: Oczkowski
authors.forename: Demetrios J
authors.initials: DJ
authors.lastname: Sahlas
authors.forename: Heather E
authors.initials: HE
authors.lastname: Murray
authors.forename: Ariane
authors.initials: A
authors.lastname: MacKey
authors.forename: Steve
authors.initials: S
authors.lastname: Verreault
authors.forename: George A
authors.initials: GA
authors.lastname: Wells
authors.forename: Ian G
authors.initials: IG
authors.lastname: Stiell
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D002170:Canada; D003920:Diabetes Mellitus / Q000175:diagnosis; D042241:Early Diagnosis; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment / Q000379:methods*; D012680:Sensitivity and Specificity; D020521:Stroke / Q000175:diagnosis*; D011795:Surveys and Questionnaires; D013997:Time Factors; D014218:Triage / Q000379:methods