Association of rhythm control with incident dementia among patients with atrial fibrillation: a nationwide population-based cohort study

Background: Atrial fibrillation (AF) increases the risk of dementia, and catheter ablation of AF may be associated with a lower risk of dementia. We investigated the association of a rhythm-control strategy for AF with the risk of dementia, compared with a rate-control strategy. Methods: This population-based cohort study included 41,135 patients with AF on anticoagulation who were newly treated with rhythm-control (anti-arrhythmic drugs or ablation) or rate-control strategies between 1 January 2005 and 31 December 2015 from the Korean National Health Insurance Service database. The primary outcome was all-cause dementia, which was compared using propensity score overlap weighting. Results: In the study population (46.7% female; median age: 68 years), a total of 4,039 patients were diagnosed with dementia during a median follow-up of 51.7 months. Rhythm control, compared with rate control, was associated with decreased dementia risk (weighted incidence rate: 21.2 versus 25.2 per 1,000 person-years; subdistribution hazard ratio [sHR] 0.86, 95% confidence interval [CI] 0.80-0.93). The associations between rhythm control and decreased dementia risk were consistently observed even after censoring for incident stroke (sHR 0.89, 95% CI 0.82-0.97) and were more pronounced in relatively younger patients and those with lower CHA2DS2-VASc scores. Among dementia subtypes, rhythm control was associated with a lower risk of Alzheimer's disease (sHR 0.86, 95% CI 0.79-0.95). Conclusions: Among anticoagulated patients with AF, rhythm control was associated with a lower risk of dementia, compared with rate control. Initiating rhythm control in AF patients with fewer stroke risk factors might help prevent subsequent dementia.