Ischemic stroke in patients with atrial fibrillation and low cardiovascular risk profile: A nationwide, registry-based cohort study

BackgroundAlthough there is substantial evidence supporting the prevention of ischemic stroke (IS) in high-risk patients with atrial fibrillation (AF), knowledge regarding AF patients with a low cardiovascular risk profile remains limited. Furthermore, the necessity of anticoagulant therapy in this population has been widely debated. MethodsData from Swedish health registers were utilized to identify all patients diagnosed with AF but without prior cardiovascular conditions between 1987 and 2018. The risk of IS was assessed using Cox regression models, with AF patients compared to age- and sex-matched controls without AF. ResultsThe study included a total of 229,075 patients with AF and 455,541 matched controls without AF. The overall risk of IS was 2.3 times higher (95% confidence interval [CI] 2.2-2.3) in patients with AF compared to controls over a mean follow-up period of 9 years (range 3-32 years). Women with AF had a 4.4-fold increased risk of developing IS within the first year following diagnosis (hazard ratio [HR] 4.4, CI 4.2-4.7) compared to matched women without AF. Additionally, younger patients with AF (aged 35-49 years) exhibited the highest risk of IS within the first year after diagnosis (HR 8.3, 95% CI 4.0- 17.1). ConclusionsThis large, nationwide, register-based cohort study found that even in the absence of cardiovascular conditions, patients with atrial fibrillation had more than double the risk of ischemic stroke compared to matched controls. The risk was especially elevated in women and younger individuals, particularly within the first year after AF diagnosis. These findings underscore the urgent need to refine risk stratification and explore preventive strategies beyond traditional clinical risk factors.