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.