The association of atrial fibrillation and dementia incidence: a meta-analysis of prospective cohort studies

Objectives To assess and synthesize the prospective cohort studies published so far on the association between atrial fibrillation (AF) and dementia incidence. Methods We searched PubMed, Web of Science, and the Cochrane Library for potential studies published in English previous to April 2018. Two independent reviewers screened the search results for prospective cohort studies reporting the association between AF and dementia incidence in patients with normal cognitive function at baseline and not suffering from an acute stroke. The Newcastle-Ottawa Scale was adopted to evaluate the quality of the included studies. The pooled hazard ratio (HR) of AF for dementia was calculated with the Comprehensive Meta-Analysis software, version 2. Heterogeneity and publication bias were assessed with the I2 test and funnel plot, respectively. Results We finally identified 11 prospective cohort studies covering 112,876 patients. All the included studies reported an adjusted HR obtained in multiple Cox regression models. The qualities of the included studies ranged from moderate to high. In pooled analysis with a fixed-effects model, AF was independently associated with dementia incidence (HR = 1.34, 95% CI: 1.24–1.44). Subgroup analysis of studies considering anticoagulation as an important confounding factor achieved a similar result. Based on the I2 test and funnel plot, we did not detect obvious heterogeneity and publication bias in our study. Meta-regression on age did not find significant results. Conclusions The results of our meta-analysis further confirmed that AF was an independent risk factor for dementia in patients with normal baseline cognitive function not suffering from acute stroke. Screening for dementia in AF patients and including dementia as an independent outcome in large AF treatment trials is warranted.