The long-term risk of atrial fibrillation after ischemic stroke: A propensity score matching analysis

Background: Although atrial fibrillation (AF) is a known risk factor for ischemic stroke (IS), few studies have evaluated the risk of AF after IS.Aim: We evaluated associations between IS and subsequent AF risk in the Korean population.Methods: We identified 98,076 participants newly diagnosed with IS between 2010 and 2018 who underwent health screening within the 2 years prior to IS diagnosis, and 98,076 propensity score matched controls were included. The risk of AF was estimated using a Fine and Gray model, with death as a competing event.Results: During the mean follow-up period of 4.7 years, 9611 participants developed AF (6728 with IS and 2883 controls). The IS patients had a greater risk of AF (sub-distribution hazard ratio [sHR] 2.32, 95% confidence interval [CI] 2.22-2.42) than the controls, and this association was more prominent during the first year after IS (sHR 7.32, 95% CI 6.59-8.13). After 1 year, the increased risk of AF was attenuated but remained elevated (sHR 1.64, 95% CI 1.56-1.73). While IS patients with severe disability had the greatest risk of AF during the first year after IS (sHR 8.92, 95% CI 7.23-11.01), this finding was not evident after more than 1 year.Conclusions: The IS patients were at significantly greater risk of AF during the first year following IS diagnosis. Although the risk was attenuated after 1 year, it remained elevated. Physicians should be aware of the elevated risk of AF in IS patients and take appropriate measures to identify and treat AF.