To assess the association between immigration status and ethnicity and the outcomes of mortality and vascular event recurrence following ischemic stroke.

We conducted a retrospective cohort study using linked administrative and clinical registry-based retrospective cohort study in Ontario, Canada from April 1, 2002 to March 31, 2018. The primary outcome was all-cause mortality and the secondary outcome was vascular event recurrence (composite of stroke or myocardial infarction). We calculated inverse probability of treatment weighted-adjusted hazard ratios (HR) of death and vascular event recurrence, with death treated as a competing risk for the latter, in immigrants compared to long-term residents using Cox models, accounting for age, sex, income and comorbidities.

We included 31,918 adult patients, of whom 2,740 (8.6%) were immigrants. Compared to long-term residents, immigrants were younger at the time of stroke (median age 70 vs. 76 years), and over a median follow-up time of 5.4 years had a lower crude mortality (74.9 vs. 123.6 per 1000 person-years) and vascular event recurrence rate (55.1 vs. 59.1 per 1000 person-years). After adjusting for age and other factors, the hazard of death (HR 0.94; 95% confidence interval 0.88 to 1.00) was similar in immigrants and long-term residents, but was lower for immigrants compared to long-term residents among those who had stroke under the age of 75 (HR 0.82; 0.74 to 0.91).

Long-term mortality following ischemic stroke is similar in immigrants and long-term residents, but modified by age at the time of stroke.