Risk of Stroke in Atrial Fibrillation According to Sex in Patients Aged Younger Than 75 Years: A Large-Scale, Observational Study Using Real-World Data.

Background It is unclear whether women have a higher risk of stroke than men. This study aimed to clarify the effects of a sex difference on the risk of ischaemic stroke in patients with atrial fibrillation (AF). Methods Health check and insurance claims data were used of people who were aged Results Of the 9,733 participants, 7,079 (72.7%) were men. The mean age of women (54.4 years) was significantly higher than that of men (53.2 years). During a mean 2.5-year follow-up period, 143 ischaemic stroke events occurred. Female sex was not associated with ischaemic stroke (adjusted hazard ratio [95% confidence interval]: 1.13 [0.78–1.66]). When stratified using the CHA2DS2-VaSc score, the annual incidence of ischaemic stroke was similarly low among women with a CHA2DS2-VaSc score of 1 (0.8%) and men with a score of 0 (0.7%). The incidence of ischaemic stroke increased with a CHA2DS2-VaSc score of 2 in women and 1 in men. Conclusions In this large-scale, real-world study of patients with AF, the risk of ischaemic stroke among those aged