Trends of anticoagulant use and outcomes of patients with non-valvular atrial fibrillation: Findings from the RAFFINE registry

Background The management of non-valvular atrial fibrillation (AF) has evolved with the development of direct oral anticoagulants (DOACs). However, data regarding the effectiveness and safety of DOACs outside clinical trial settings are limited, and off-label dosing of DOACs has not been thoroughly investigated. Methods We examined the clinical outcomes of patients with non-valvular AF in the RAFFINE registry, a prospective registry of Japanese patients with AF who were followed-up for more than 3 years. Results Among 3706 patients with non-valvular AF, 42.5% received warfarin and 44.7% received DOACs at baseline. The administration of DOACs increased annually. The mean CHADS2 and HAS-BLED scores were significantly higher in the warfarin group. The unadjusted all-cause mortality, cardiovascular mortality, and incidence of major bleeding events were higher in the warfarin group. The incidence of ischemic stroke/systemic embolism was not different between groups. After adjustment for baseline characteristics, the incidence of these events was not different between groups. Off-label dosing was performed for 32% of patients in the DOAC group, but this did not affect clinical outcomes. Conclusions The all-cause mortality, cardiovascular mortality, and incidence of major bleeding events were higher in the warfarin group than in the DOAC group. After adjustment, warfarin use was not associated with an increase in these events. Off-label dosing of DOACs is not rare and is not associated with reduced effectiveness. The impact of off-label dosing of each DOAC on clinical events should be assessed using a larger population.