Prospective validation of the ABCD2 score for patients in the emergency department with transient ischemic attack
Jeffrey J Perry1, Mukul Sharma, Marco L A Sivilotti
1Department of Emergency Medicine, University of Ottawa, Ottawa, Ont. jperry@ohri.ca
Insights
The ABCD2 score is not accurate for predicting stroke risk after transient ischemic attack. This study found the score to be unreliable in emergency department patients.
Area of Science:
- Neurology
- Emergency Medicine
- Clinical Risk Stratification
Background:
- The ABCD2 score is widely used to assess stroke risk in transient ischemic attack (TIA) patients.
- Prospective validation of the ABCD2 score's accuracy has been lacking.
- This study aimed to prospectively evaluate the ABCD2 score's predictive performance for stroke.
Purpose of the Study:
- To assess the accuracy of the ABCD2 score in predicting stroke at 7 and 90 days post-TIA.
- To evaluate the sensitivity and specificity of different ABCD2 score cut-points for stroke prediction.
Main Methods:
- A prospective cohort study was conducted in eight Canadian emergency departments.
- Adults diagnosed with TIA were enrolled, and physicians calculated ABCD2 scores.
- Stroke outcomes were confirmed by neurologists or an Adjudication Committee.
Main Results:
- 2056 patients were enrolled; stroke rates were 1.8% at 7 days and 3.2% at 90 days.
- An ABCD2 score >5 showed low sensitivity (29.2-31.6%) for predicting stroke.
- An ABCD2 score >2 had high sensitivity (94.7%) but poor specificity (12.5%) for 7-day stroke.
Conclusions:
- The ABCD2 score is inaccurate for predicting imminent stroke in TIA patients across all cut-points.
- The American Heart Association's recommended ABCD2 score cut-point of >2 lacks specificity.
- Clinical decision-making for TIA patients requires more reliable risk assessment tools.
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 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.
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