Five-Year Risk of Stroke After TIA or Minor Ischemic Stroke

Background: After a transient ischemic attack (TIA) or minor stroke, the long-term risk of stroke and other vascular events is not well known. In this follow-up to a report on 1-year outcomes from a registry of TIA clinics in 21 countries that enrolled 4789 patients with a TIA or minor ischemic stroke from 2009 through 2011, we examined the 5-year risk of stroke and vascular events.

Methods: We evaluated patients who had had a TIA or minor stroke within 7 days before enrollment in the registry. Among 61 sites that participated in the 1-year outcome study, we selected 42 sites that had follow-up data on more than 50% of their enrolled patients at 5 years. The primary outcome was a composite of stroke, acute coronary syndrome, or death from cardiovascular causes (whichever occurred first), with an emphasis on events that occurred in the second through fifth years. In calculating the cumulative incidence of the primary outcome and secondary outcomes (except death from any cause), we treated death as a competing risk.

Results: A total of 3847 patients were included in the 5-year follow-up study; the median percentage of patients with 5-year follow-up data per center was 92.3% (interquartile range, 83.4 to 97.8). The composite primary outcome occurred in 469 patients (estimated cumulative rate, 12.9%; 95% confidence interval [CI], 11.8 to 14.1), with 235 events (50.1%) occurring in the second through fifth years. At 5 years, strokes had occurred in 345 patients (estimated cumulative rate, 9.5%; 95% CI, 8.5 to 10.5), with 149 of these patients (43.2%) having had a stroke during the second through fifth years. Rates of death from any cause, death from cardiovascular causes, intracranial hemorrhage, and major bleeding were 10.6%, 2.7%, 1.1%, and 1.5%, respectively, at 5 years. In multivariable analyses, ipsilateral large-artery atherosclerosis, cardioembolism, and a baseline ABCD score for the risk of stroke (range, 0 to 7, with higher scores indicating greater risk) of 4 or more were each associated with an increased risk of subsequent stroke.

Conclusions: In a follow-up to a 1-year study involving patients who had a TIA or minor stroke, the rate of cardiovascular events including stroke in a selected cohort was 6.4% in the first year and 6.4% in the second through fifth years. (Funded by AstraZeneca and others.).