Association between depression and risk of ischaemic stroke in patients with atrial fibrillation

Aims Atrial fibrillation (AF) is a major cause of ischaemic stroke (IS), and its risk is assessed using existing risk stratification scores. However, the impact of psychiatric comorbidities such as depression on this risk has not been sufficiently considered. Depression is commonly observed in individuals with AF and is increasingly recognized as an independent risk factor for IS. This study aimed to examine the association between depression and the risk of IS in AF. Methods and results A cohort study of individuals with AF was conducted using a large Japanese healthcare database. Hazard ratios (HR) for IS in patients with depression were estimated using a multivariable Cox proportional hazards model, adjusting for established cardiovascular risk factors and medication use (e.g. anticoagulant therapy). Additional analyses included age- and sex-stratified analyses, time-dependent models, and sensitivity analyses to assess reverse causality bias. A total of 22 939 individuals with AF were included in the analysis. Among them, 1774 patients (7.7%) had a diagnosis of depression at baseline. During follow-up, IS occurred at a higher rate in individuals with depression. Multivariate analysis demonstrated that depression was an independent and significant predictor for IS (HR 1.39, 95% confidence interval 1.16–1.66, P < 0.001). Stratified analysis by age revealed this association was particularly pronounced in younger individuals. Conclusion This study demonstrates that depression in individuals with AF is a predictor of IS, independent of established cardiovascular risk factors. These findings highlight the potential importance of screening for depression as part of the holistic risk assessment for patients with AF.