Clinical implications of different types of dementia in patients with atrial fibrillation: Insights from a global federated health network analysis

Background: Atrial fibrillation (AF) associates with higher Alzheimer’s disease (AD) and vascular dementia risks but the clinical implications have been scarcely investigated. We examined the association between AD or vascular dementia and adverse outcomes in AF patients. Methods: Cohort study between January 2000 and 2017. AF patients were divided into two groups according to vascular dementia or AD, and balanced using propensity score matching (PSM). During 4-years of follow-up, incident intracranial haemorrhages (ICH), the composite of ischemic stroke/transient ischemic attack (TIA), hospitalizations, and all-cause deaths, were recorded. Results: 2,377 AF patients with dementia (1,225 with vascular dementia, and 1,152 with AD) were identified. Following a PSM, 615 patients were included in each cohort (i.e. 1:1) and all variables were well-matched. After PSM, 22 (3.6%) patients with vascular dementia and 55 (8.1%) patients with AD had incident ICH during follow-up (hazard ratio [HR] 2.22, 95% confidence interval [CI] 1.33-3.70, log-rank p-value=0.002). Overall, 237 (38.5%) patients with vascular dementia and 193 (31.4%) patients with AD, developed an ischemic stroke/TIA. The risk of ischemic stroke/TIA was 1.32-fold higher in vascular dementia (HR 1.32, 95% CI 1.09-1.59, log-rank p-value=0.003). The risk of re-hospitalization (HR 1.14, 95% CI 1.01-1.31), and mortality (HR 1.25, 95% CI 1.01-1.58) were also higher among AF patients with vascular dementia compared to AD. Conclusions: The two forms of dementia in AF patients are associated with different prognosis, with AD being associated with a higher risk of ICH, and vascular dementia with a higher risk of stroke/TIA, hospitalization and mortality.