Long-term risk of recurrent stroke after a first-ever stroke. The Oxfordshire Community Stroke Project.

BACKGROUND AND PURPOSE

There have been few community-based studies of long-term prognosis after acute stroke. This study aims to provide precise estimates of the absolute and relative risks of stroke recurrence in an unselected cohort of patients with a first-ever stroke.

METHODS

Six hundred seventy-five patients were registered in a community-based stroke register (the Oxfordshire Community Stroke Project) and prospectively followed for up to 6.5 years. Their relative risk of recurrent stroke was calculated using age- and sex-specific incidence rates for first stroke in Oxfordshire.

RESULTS

One hundred eighty recurrent episodes of stroke were identified, of which 135 were first recurrences. Given survival, the actuarial risk of suffering a recurrence was 30% (95% confidence interval, 20% to 39%) by 5 years, about nine times the risk of stroke in the general population. The risk was highest early after the first stroke: 13% (95% confidence interval, 10% to 16%) by 1 year, 15 times the risk in the general population. After the first year the average annual risk was about 4%. The risk of stroke recurrence did not appear to be related to age or pathological type of stroke.

CONCLUSIONS

The absolute and relative risks of recurrent stroke are highest early after the first stroke but remain elevated for several years thereafter. Efforts at secondary prevention should be initiated as soon as possible and continued for several years to gain greatest benefit.