Risk of incident atrial fibrillation and subsequent use of oral anticoagulants in patients with dementia

Abstract Background Dementia and atrial fibrillation (AF) have many shared risk factors, and the presence of AF is associated with a higher risk of incident dementia. Although patients with dementia have higher risk of adverse cardiovascular events, there are limited data on the risks of incident AF, and the associated AF-related clinical outcomes. Patients with dementia are under-represented in randomised trials, and even if AF is present, oral anticoagulants (OAC) are not prescribed frequently. We aimed to report the incidence of newly-diagnosed AF in dementia patients, and the impact on stroke and bleeding outcomes with vitamin K antagonist (VKA, eg warfarin) and non-VKA OAC (NOACs). Methods Nationwide cohort study of 544,074 patients with dementia, compared to 554,074 age- and sex-matched patients without dementia. Results Rates of newly-diagnosed AF were higher in patients with dementia compared to those without history of dementia (1.89 per 100 person-years vs 1.78 per 100 person-years, respectively); adjusted risk of incident AF was greater in all types of dementia, pre-senile/senile dementia and vascular dementia (Figure 1). When compared to non-OAC users, warfarin use was associated with higher risk of ischaemic stroke (aHR, 1.290; 95% CI, 1.156 - 1.440), intracranial hemorrhage (ICH) risk (aHR, 1.678; 95% CI, 1.346 - 2.09) and major bleeding (aHR, 1.192; 95% CI, 1.073 - 1.323). NOAC use was associated with lower risk of ischaemic stroke (aHR, 0.42; 95% CI, 0.352 - 0.501) and major bleeding (aHR; 0.504, 95% CI, 0.433 - 0.587), when compared to non-OAC use (Figure 2). Conclusions In this large nationwide cohort of dementia patients, the incidence rate of newly-diagnosed or incident AF was higher in patients with dementia compared to patients without dementia. Compared to non-OAC users, NOAC use was associated with a lower risk of ischaemic stroke and major bleeding. Patients with dementia require a holistic approach to their care and management, including the use of NOACs to reduce their risks of clinical events.