Validation and Refinement of the ABCD2 Score A Population-Based Analysis

Background and Purpose-Transient ischemic attacks are a frequent diagnosis in the emergency department setting, yet expert opinion as to the proper follow-up and need for hospitalization differs widely. Recently, an effort has been made to risk-stratify patients presenting with transient ischemic attacks through scoring systems such as the ABCD and ABCD2 scales. The aim of our study was to independently validate these scores using a population-based cohort. Methods-Using the data from the Rochester Stroke and Transient Ischemic Attack Registry and resources of the Rochester Epidemiology Project, medical records of all residents of Rochester, Minn, with a diagnosis of incident transient ischemic attack from 1985 through 1994 were examined (N = 284). Patients were scored on the ABCD and ABCD2 scales and new scores were created by adding hyperglycemia and a history of hypertension. The end points of stroke and death were collected previously and were verified through the Rochester Epidemiology Project data. Results-Although our study did find that scores > 4 had a statistically significant predictive value for future stroke, a substantial proportion of strokes within 7 days (9 of 36 cases [25%]) occurred in patients with low or intermediate risk scores (<= 4) on the ABCD2 scale. Including history of hypertension and hyperglycemia on presentation increased the sensitivity of the score to identify patients who had a stroke within 7 days. Conclusions-Reliance on the ABCD and ABCD2 scores misses some patients who will have a stroke within 7 days of a transient ischemic attack. Adding hyperglycemia and a history of hypertension to the predictive model could be useful, but the value of these additions need to be evaluated further. (Stroke. 2009; 40: 2669-2673.)