Poor performance of current prognostic scores for early risk of recurrence after minor stroke

Abstract

Background and purpose: The ABCD(2) score predicts the early risk of stroke after transient ischemic attack. The early risk of recurrence after minor stroke is as high but the only validated prognostic scores for use in minor stroke predict long-term risk of recurrence: the Essen Stroke Risk Score and the Stroke Prognosis Instrument II.

Methods: We determined the prognostic value of the ABCD(2) score, Essen Stroke Risk Score, and Stroke Prognosis Instrument II in a prospective population-based study in Oxfordshire, UK, of all incident and recurrent stroke (Oxford Vascular Study). Minor stroke was defined as an National Institutes of Health Stroke Scale score ≤5 at the time of first assessment. The 90-day risks of recurrent stroke were determined in relation to each score. Areas under the receiver operator curves indicated predictive value.

Results: Of 1247 first events in the study period, 488 were transient ischemic attacks, 520 were minor strokes, and 239 were major strokes. The ABCD(2) score was modestly predictive (area under the receiver operator curve, 0.64; 0.53 to 0.74; P=0.03) of recurrence at 7 days after minor stroke and at 90 days (0.62; 0.54 to 0.70; P=0.004). Neither Essen Stroke Risk Score (0.50; 0.42 to 0.59; P=0.95) nor Stroke Prognosis Instrument II (0.48; 0.39 to 0.60; P=0.92) were predictive of 7-day or 90-day risk of recurrent stroke. Of the traditional vascular risk factors, etiologic classification (Trial of ORG 10172 in Acute Stroke Treatment) and variables in the ABCD(2) score, only blood pressure >140/90 mm Hg (hazard ratio, 2.75; 1.18 to 6.38; P=0.02) and large artery disease (hazard ratio, 2.21; 1.00 to 4.88; P=0.05) were predictive of 90-day risk.

Conclusions: The predictive power of the ABCD(2) score is modest in patients with minor stroke, and neither the Essen Stroke Risk Score nor the Stroke Prognosis Instrument II predicts early recurrence. More reliable early risk prediction after minor stroke is required.