Ischaemic stroke patients face high recurrence risk for at least five years, with more than 7% experiencing another event in the first year alone, a large cohort study has found.

The study, published in the Journal of Neurology [link here], analysed more than 114,000 patients from England and Denmark who had a first non-cardioembolic ischaemic stroke between 2012 and 2021.

Recurrent ischaemic stroke occurred in 11% of English patients and 15% of Danish patients over a mean follow-up of 3.0 and 3.9 years respectively. Incidence rates were similar across both cohorts (3.74 and 3.87 per 100 person-years).

Risk was steepest immediately after discharge. Incidence rates in the first month reached 26.6 and 22.8 per 100 person-years in England and Denmark respectively, falling to 7.39 and 7.96 in the first year, then dropping further in subsequent years. Despite this decline, cumulative hazard at five years remained high, at 16.5 and 18.1 per 100 person-years.

Recurrent events were also more severe than the original stroke: among Danish patients with severity data available, moderate strokes were more common at recurrence (19.0% vs 13.8%), as were severe strokes (7.9% vs 3.6%).

Risk factors

Older age was the strongest predictor of recurrence. Patients over 75 had an adjusted hazard ratio (aHR) of 1.59 (England) and 2.07 (Denmark) compared to those under 65.

In the English cohort, frailty at the time of the index stroke was also associated with higher recurrence risk (aHR 1.25 and 1.40 for mild and severe frailty respectively).

Stroke severity on admission, available only in a Danish sub-cohort (n=5,540), strongly predicted recurrence: aHR 2.12 for severe and 1.51 for moderate, compared to mild.

Most other baseline factors showed only weak associations.

“These findings highlight a continued burden of secondary stroke despite advances in prevention approaches over the last decade,” wrote the authors, who included Professor Deborah Lowe, a consultant stroke physician and geriatrician at Wirral University Teaching Hospital NHS Foundation Trust.

The study drew on linked primary care and hospital data in England and national registry data in Denmark, enabling analysis of frailty, BMI and eGFR alongside stroke severity scores. The authors said the consistency of results across two national healthcare systems strengthened generalisability.

The study was sponsored by Bayer AG and co-authored by company representatives.