Risk of dementia in patients with atrial fibrillation: Short versus long follow-up. A systematic review and meta-analysis

Background: No previous meta-analyses have compared the risk of dementia, due to an underlying atrial fibrillation (AF), in the short-term versus the long-term period. Aim: To perform an update meta-analysis of studies examining the association between AF and dementia and the relative impact of follow-up period. Methods: Data were obtained searching MEDLINE and Scopus for all investigations published between 1 January 2000 and March 1, 2021 reporting the risk of dementia in AF patients. The following MeSH terms were used for the search: “Atrial Fibrillation” AND “Dementia” OR “Alzheimer’s disease”. From each study, the adjusted hazard ratio (aHR) with the related 95% confidence interval (CI) was pooled using a random effect model. Results: The analysis was carried out on 18 studies involving 3.559.349 subjects, of which 902.741 (25.3%) developed dementia during follow-up. A random effect model revealed an aHR of 1.40 (95% CI: 1.27–1.54, p < 0.0001; I2 = 93.5%) for dementia in subjects with AF. Stratifying the studies according to follow-up duration, those having a follow-up ≥10 years showed an aHR for dementia of 1.37 (95% CI: 1.21–1.55, p < 0.0001, I2 = 96.6%), while those with a follow-up duration <10 years has a slightly higher aHR for dementia (HR: 1.59, 95%CI: 1.51–1.67, p < 0.0001, I2 = 49%). Nine studies showed that the aHR for Alzheimer’s disease (AD) in AF patients was 1.30 (95%CI: 1.12–1.51, p < 0.0001, I2 = 87.6%). Conclusions: Evidence suggests that patients with AF have an increased risk of developing dementia and AD. The risk of dementia was slightly higher when the follow-up was shorter than 10 years.