Prognosis in patients with transient ischaemic attack (TIA) and minor stroke attending TIA services in the North West of England: The NORTHSTAR Study

Background: The ABCD(2) score predicts stroke risk within a few days of transient ischaemic attack (TIA). It is not clear whether the predictive value of the ABCD(2) score can be generalised to UK TIA services, where delayed presentation of TIA and minor stroke are common. We investigated prognosis, and the use of the ABCD(2) score, in patients attending TIA services in the North West of England with a diagnosis of TIA or minor stroke. Methods: 711 patients with TIA or minor stroke were prospectively recruited from five centres (median duration from index event to recruitment 15 days). The primary outcome was the composite of incident TIA, stroke, acute coronary syndrome or cardiovascular death at the 3 month follow-up. Prognostic factors were analysed using Cox proportional hazards regression. Results: The primary outcome occurred in 126 (18%) patients. Overall, there were 30 incident strokes. At least one incident TIA occurred in 100 patients (14%), but only four had a subsequent stroke. In multifactorial analyses, the ABCD2 score was unrelated to the risk of the primary outcome, but predicted the risk of incident stroke: score 4-5: hazard ratio (HR) 3.4 (95% CI 1.0 to 12); score 6-7: HR 4.8 (1.3 to 18). Of the components of the ABCD2 score, unilateral motor weakness predicted both the primary outcome ( HR 1.8 (1.2 to 2.8)) and stroke risk ( HR 4.2 (1.3 to 14)). Conclusions: In patients attending typical NHS TIA services, the risk of incident stroke was relatively low, probably reflecting delays to assessment. Current provision of TIA services, where delayed presentation to "rapid access'' TIA clinics is common, does not appear to provide an appropriate setting for urgent evaluation, risk stratification or timely secondary prevention for those who may be at highest risk.