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.Interpretation: This multicentre prospective study involving patients in emergency departments with transient ischemic attack found the ABCD2 score to be inaccurate, at any cutpoint, as a predictor of imminent stroke. Furthermore, the ABCD2 score of more than 2 that is recommended by the American Heart Association is nonspecific. AbstractSee related commentary by Hill and Coutts on page 1127 and at

Isolated transient aphasia at emergency presentation is associated with a high rate of cardioembolic embolism

“…Speech disturbance is a component of the ABCD 2 score, a tool developed to predict the risk of stroke after TIA, 25 even if an independent verification analysis has found this score to be inaccurate and nonspecific. 12 It is possible that the accuracy of scoring tools may be improved by including aphasia, only when it occurs in the absence of other deficits or studying other interactions between components of the score.…”

“…12 Ethics board approval was obtained at all participating sites. The combined annual census at all participating sites was 394,000 visits.…”

“…Details regarding patient selection and data collection for this population have been previously described. 12 Patients were excluded for 1) neurological deficit >24 hours at presentation, 2) decreased level of consciousness (i.e., Glasgow Coma Scale score of <15), 3) obvious alternate cause for the deficit other than TIA (e.g., hypoglycemia, seizure, electrolyte imbalance, migraine), 4) receiving tissue plasminogen activator, or 5) presentation to the enrolling emergency department >7 days after TIA. The diagnosis of TIA was defined using the World Health Organization definition: a sudden, focal neurological deficit lasting for less than 24 hours, presumed to be of vascular origin, and confined to an area of the brain or eye perfused by a specific artery.…”

National survey of emergency physicians for transient ischemic attack (TIA) risk stratification consensus and appropriate treatment for a given level of risk

“…Such a cut-point resulted in an excellent sensitivity for stroke at 7 days but poor specificity. 23 According to these guidelines on managing suspected TIA patients, many resources would be used on patients not at risk for stroke, which is not pragmatic or costefficient to the health care system. Based on our survey results, physicians are able to define risk strata for impending stroke and have specific management recommendations for each.…”

“…[17][18][19][20][21][22] Unfortunately, the ACBD2 Score has not performed well in prospective validation (c-statistic: 0.56). 23 We recently conducted a prospective, multicentre study to determine clinical features of TIA patients presenting to emergency departments (EDs), associated with high risk of stroke and to develop a new clinical prediction score for impending stroke. 24 The Canadian TIA Score consists of 13 variables, identifies the risk of subsequent stroke ≤7 days, and quantifies the impending stroke risk following an ED visit for a new TIA.…”