Risk of dementia in stroke-free patients diagnosed with atrial fibrillation: Data from a population-based cohort

Aims: Atrial fibrillation (AF) is generally regarded as a risk factor for dementia, though longitudinal studies assessing the association between AF and dementia have shown inconsistent results. This study aimed to determine the effect of AF on the risk of developing dementia using a longitudinal, community-based, and stroke-free elderly cohort. Methods and results: The association of incident AF with the development of incident dementia was assessed from 2005 to 2012 in 262 611 dementia-and stroke-free participants aged ≥60 years in the Korea National Health Insurance Service-Senior cohort. Incident AF was observed in 10 435 participants over an observational period of 1 629 903 person-years (0.64%/year). During the observational period, the incidence of dementia was 4.1 and 2.7 per 100 person-years in the incident AF and propensity score-matched AF-free groups, respectively. After adjustment, the risk of dementia was significantly increased by incident AF with a hazard ratio (HR) of 1.52 [95% confidence interval (CI) 1.43-1.63], even after censoring for stroke (1.27, 95% CI 1.18-1.37). Incident AF increased the risk of both Alzheimer (HR 1.31, 95% CI 1.20-1.43) and vascular dementia (HR 2.11, 95% CI 1.85-2.41). Among patients with incident AF, oral anticoagulant use was associated with a preventive effect on dementia development (HR 0.61, 95% CI 0.54-0.68), and an increasing CHA₂DS₂-VASc score was associated with a higher risk of dementia. Conclusion: Incident AF was associated with an increased risk of dementia, independent of clinical stroke in an elderly population. Oral anticoagulant use was linked with a decreased incidence of dementia.