Prestroke dementia in patients with atrial fibrillation: Frequency and associated factors

Background and purpose: Prestroke dementia is frequent but usually not identified. Non-valvular atrial fibrillation (NVAF) is independently associated with an increased risk for dementia. However, the frequency and determinants of prestroke dementia in patients with NVAF have never been evaluated. Objective: The aim of this study was to determine the frequency of prestroke dementia and associated factors in patients with a previously known NVAF. Methods: This is an ancillary study of Stroke in Atrial Fibrillation Ensemble II (SAFE II), an observational study conducted in patients with a previously known NVAF, consecutively admitted for an acute stroke in French and Italian centers. Prestroke dementia was evaluated by the IQCODE in patients with a reliable informant. Patients were considered as demented before stroke when their IQCODE score was ≥ 104. Results: of 204 patients, 39 (19.1 %; 95 % confidence interval [CI]: 13.7 %-24.5 %) patients met criteria for prestroke dementia. The only variable independently associated with prestroke dementia was increasing age (adjusted odds ratio for 1 year increase in age: 1.10; 95 % CI: 1.04-1.17), and there was a non-significant tendency for previous ischemic stroke or TIA and arterial hypertension. Conclusion: One fifth of stroke patients with a previously known NVAF were already demented before stroke. The main determinant of prestroke dementia is increasing age. A large cohort is necessary to identify other determinants.