Long-Term Risk of Stroke Recurrence: A  Competing Risk Analysis Based on the South London Stroke Register.

BACKGROUND

Previous studies on stroke recurrence often ignored the competing risk of death, potentially biasing risk estimates. This study estimated stroke recurrence risk and identified associated factors among patients with first-ever stroke in South London while accounting for competing mortality risks.

METHODS

Data were obtained from the SLSR (South London Stroke Register), including patients with first-ever stroke between 1995 and 2019. Stroke recurrence was analyzed using the cumulative incidence function and Fine-Gray competing risk models, with death treated as a competing event.

RESULTS

A total of 5509 patients were included, of whom 4692 (85.1%) had ischemic stroke (IS) and 817 (14.8%) hemorrhagic stroke. During 34 874 person-years of follow-up, 680 (12.3%) stroke recurrences and 2666 (48.4%) deaths were observed. Most recurrent strokes were ISs (75.3%). The cumulative recurrence risk was 9.6%, 14.1%, and 15.2% at 5, 15, and 25 years, respectively. The 10-year recurrence risk was higher after IS (12.7%) than hemorrhagic stroke (11.1%). For IS, higher recurrence risk was associated with earlier cohorts, Black race (subdistribution hazard ratio [SHR], 1.28 [95% CI, 1.04-1.58]), hypertension (SHR, 1.45 [95% CI, 1.18-1.78]), transient ischemic attack (SHR, 1.35 [95% CI, 1.06-1.70]), and lack of hospital admission (SHR, 1.40 [95% CI, 1.07-1.82]). For hemorrhagic stroke, recurrence risk was higher among patients with diabetes (SHR, 1.89 [95% CI, 1.10-3.23]) and differed by hemorrhage subtype.

CONCLUSIONS

Stroke recurrence risk remains substantial following both IS and hemorrhagic stroke. Accounting for death as a competing risk provides more accurate estimates and highlights the importance of demographic and clinical factors in recurrence prevention.