A Multicenter Evaluation of the ABCD2 Score's Accuracy for Predicting Early Ischemic Stroke in Admitted Patients With Transient Ischemic Attack

Study objective: We evaluate, in admitted patients with transient ischemic attack, the accuracy of the ABCD 2 (age [A], blood pressure [13], clinical features [weakness/speech disturbance] [C], transient ischemic attack duration [D], and diabetes history [D]) score in predicting ischemic stroke within 7 days. Methods: At 16 North Carolina hospitals, we enrolled a prospective, nonconsecutive sample of admitted patients with transient ischemic attack and with no stroke history, presenting within 24 hours of transient ischemic attack symptom onset. We conducted a medical record review to determine ischemic stroke outcomes within 7 days. According to a modified Rankin Scale Score, strokes were classified as disabling (>2) or nondisabling (<= 2). Results: During a 35-month period, we enrolled 1,667 patients, of whom 373 (23%) received a diagnosis of an ischemic stroke within 7 days. Eighteen percent (69/373) of all strokes were disabling. We were unable to calculate an ABCD 2 score in 613 patients (37%); however, our imputed analysis indicated this did not significantly alter results. The discriminatory power of the ABCD 2 score was modest for ischemic stroke in 7 days (c statistic 0.59), and fair for disabling ischemic stroke within 7 days (c statistic 0.71). Patients characterized as low risk according to ABCD 2 Score (:53) were at low risk for experiencing a disabling stroke within 7 days, with a negative likelihood ratio of 0.16 (95% confidence interval [CI] 0.04 to 0.64) with missing values excluded and 0.34 (95% Cl 0.15 to 0.76) when missing values were imputed. Conclusion: Our analysis suggests the best application of the ABCD 2 score may be to identify patients at low risk for an early disabling ischemic stroke. Further study of the ability to determine an ABCD 2 score in all patients is needed, along with validation in a large, consecutive population of patients with transient ischemic attack. [Ann Emerg Med. 2010;55:201-210.]