National trends in hospital admission, case fatality, and sex differences in atrial fibrillation-related strokes

Background and aim: Atrial fibrillation is associated with increased risk of ischemic stroke and its global prevalence is increasing. We aimed to describe the contemporary temporal trends in hospital admissions, case fatality rate, as well as sex differences in atrial fibrillation-related stroke in Canada.

Methods: We conducted a retrospective cohort study using Canadian national administrative data to identify admissions to hospital for stroke with comorbid atrial fibrillation between 1 April 2007 and 31 March 2016. We determined temporal trends in the crude and the age- and sex-standardized admission and case fatality rates. We also evaluated for any sex differences in these outcomes.

Results: There were 222,100 admissions to hospital for ischemic (n = 182,990) or hemorrhagic (n = 39,110) stroke. Comorbid atrial fibrillation was present in 20.2% of admissions for ischemic strokes and 10.1% for hemorrhagic strokes. Over the study period, the age-sex adjusted proportion of admissions with atrial fibrillation increased from 16.3% to 20.5% (p = 0.02) for ischemic stroke and was stable for hemorrhagic stroke. In-hospital case fatality rate decreased for ischemic stroke with and without comorbid atrial fibrillation. Women aged 65 years and older with ischemic stroke were more likely to have comorbid atrial fibrillation compared to men, while this association was reversed in younger women. There were no sex differences in the case fatality rate for people with atrial fibrillation-related ischemic stroke.

Conclusion: Atrial fibrillation is present in an increasing proportion of people hospitalized in Canada with ischemic stroke and disproportionately affects older women. Renewed focus is needed on atrial fibrillation-related stroke prevention with particular attention to sex disparities.