Risks of Stroke Recurrence and Mortality After First and Recurrent Strokes in Denmark

Background and Objectives To examine risks of stroke recurrence and mortality after first and recurrent stroke. Methods Using Danish nationwide health registries, we included patients age ≥18 years with first-time ischemic stroke (n = 105,397) or intracerebral hemorrhage (ICH) (n = 13,350) from 2004 to 2018. Accounting for the competing risk of death, absolute risks of stroke recurrence were computed separately for each stroke subtype and within strata of age groups, sex, stroke severity, body mass index, smoking, alcohol use, Essen stroke risk score, and atrial fibrillation. Mortality risks were computed after first and recurrent stroke. Results After adjusting for competing risks, the overall 1-year and 10-year risks of recurrence were 4% and 13% following first-time ischemic stroke and 3% and 12% following first-time ICH. For ischemic stroke, the risk of recurrence increased with age and was higher for men and following mild vs more severe stroke. The most marked differences were across Essen risk scores, for which recurrence risks increased with increasing scores. For ICH, risks were similar for both sexes and did not increase with Essen risk score. For ischemic stroke, the 1-year and 10-year risks of all-cause mortality were 17% and 56% after a first-time stroke and 25% and 70% after a recurrent stroke; corresponding estimates for ICH were 37% and 70% after a first-time event and 31% and 75% after a recurrent event. Discussion The risk of stroke recurrence was substantial following both subtypes, but risks differed markedly among patient subgroups. The risk of mortality was higher after a recurrent than first-time stroke.