Johnston SC et al. (2007) Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet 369: 283–292

Patients presenting with transient ischemic attack (TIA) have a high risk of subsequent stroke, especially in the very short term. In this study, Johnston and co-workers have evaluated two existing scores, the California and ABCD scores, which are optimized to predict 90-day and 7-day risks of stroke after TIA, respectively. The authors then combined elements from these two scores to create a single scoring system optimized to predict 2-day risk of post-TIA stroke. The unified score was validated in several large, diverse cohorts.

The two existing scores predicted 2-day, 7-day and 90-day stroke risks similarly well in four independent validation cohorts (c statistics in the range 0.60–0.81). The new unified score, (named ABCD2; scored 0–7) based on age, blood pressure, clinical features and duration of TIA, and diabetes, tended to predict post-TIA stroke risks better than did either of the two existing scores (c statistics 0.62–0.83). The ABCD2 score classified 21% of the patients studied as being at high 2-day risk of stroke (risk 8.1%; score 6–7), with 45% at moderate risk (risk 4.1%; score 4–5) and the remaining 34% at low risk (risk 1.0%; score 0–3).

The authors propose that a standard 2-day risk score such as ABCD2 could be used—possibly alongside diagnostic imaging—to select those patients who would benefit most from urgent hospital admission and evaluation after TIA.