Association between immigration status and the intensity of acute stroke care in Ontario, Canada: a retrospective study

Background and objectives — Immigration status is associated with stroke incidence and outcomes; however, its association with admission to and length of stay in the intensive care unit (ICU) in patients with stroke is unknown. We aimed to determine the association between immigration status and intensity of ICU care among patients with ischemic stroke.

Methods — We conducted a population-based retrospective cohort study of adults hospitalized for ischemic stroke in Ontario, Canada, between April 1, 2014, and March 30, 2023. People born outside Canada and who arrived after 1985 were defined as immigrants. We reported rates of thrombolysis, thrombectomy (reperfusion treatments), ventilatory support, and feeding tube insertion in immigrants and long-term residents. We calculated adjusted odds ratios (aOR) of ICU admission using logistic models and adjusted risk ratios (aRR) of longer ICU stays using negative binomial models, comparing immigrants with long-term residents, in the entire cohort and among those who did not receive reperfusion treatments.

Results — Of 85,507 patients included (45% female), 12.9% were immigrants. Immigrants were younger (median age 69 years vs 76 years, standardized difference = 0.38), had lower stroke severity and rates of reperfusion, and had higher rates of life-sustaining treatments compared with long-term residents. Immigrants had similar odds of ICU admission compared with long-term residents (18.2% vs 19.7%; aOR 0.97; 95% CI 0.91–1.04), but their ICU stays were longer (mean 5.6 ± 18.5 days vs 3.8 ± 7.7 days; aRR 1.30; 1.13–1.48) in the adjusted models, and this remained the case for those who did not receive reperfusion treatments (length of stay; aRR 1.27; 1.09–1.49). These associations did not vary by whether a hospital cared for a higher-than-median proportion of immigrants across all hospitals. Immigrants who came as refugees, and those who came from Africa, East Asia, and the Middle East, had longer ICU stays than long-term residents.

Discussion — Immigrant ischemic stroke patients have similar ICU admission rates, but longer ICU stays. The longer ICU stays among immigrant stroke patients may in part be driven by higher rates of life-saving treatments; however, the impact of these differences on the long-term functional outcomes remains to be studied.