Hospital admission for stroke or transient ischemic attack among First Nations people with diabetes in Ontario: a population-based cohort study. BACKGROUND:  First Nations people have high rates of diabetes mellitus, which is a risk factor for stroke. We studied the rates of hospital admission, processes of care and outcomes of stroke and transient ischemic attack (TIA) in First Nations people in Ontario. METHODS:  Using linked administrative databases, we identified annual cohorts of people aged 20-105 years in Ontario with prevalent diabetes between Apr. 1, 1995, and Mar. 31, 2015. We identified Status First Nations people in Ontario from the Indian Register. We compared age- and sex-standardized rates of hospital admission for stroke or TIA, processes of care and case fatality among First Nations versus other people in Ontario with diabetes. RESULTS:  Overall, 28 874 people with diabetes (of whom 536 were First Nations people) were admitted to hospital with a stroke or TIA between Apr. 1, 2011, and Mar. 31, 2016. Admission rates for stroke or TIA declined over the study period but were higher among First Nations people than other Ontarians in most years after 2005/06. First Nations people admitted with stroke or TIA were as likely as other Ontarians to undergo neuroimaging within 24 hours (94.6% v. 96.0%), be discharged to inpatient rehabilitation (31.8% v. 34.8%) and receive carotid revascularization (1.4% v. 2.7%), but were less likely to receive thrombolysis (6.3% v. 11.0%). Age- and sex-standardized stroke case fatality was similar in First Nations people and other Ontarians at 7 days (12.0% v. 8.5%), 30 days (19.2% v. 16.0%) and 1 year (33.8% v. 28.1%). INTERPRETATION:  Rates of hospital admission for stroke or TIA were higher among First Nations people than other people with diabetes in Ontario. Future work should focus on determining Indigenous-specific determinants of health related to this disparity and implementing appropriate interventions to mitigate the risks and sequelae of stroke in First Nations people.