Abstract
Background: Oral anticoagulants (OACs) are effective in preventing stroke in patients with atrial fibrillation (AF), but are challenging for elderly patients because of the higher risk of bleeding complications. Methods and Results: The ANAFIE Registry is a prospective multicenter observational study of elderly (≥75 years) Japanese AF patients. This subanalysis evaluated the current use of OACs. Of 32,713 patients (mean age 81.5 years), 30,068 (91.9%) were receiving OACs, including 8,354 (25.5%) on warfarin and 21,714 (66.4%) on direct OACs (DOACs); 2,645 (8.1%) were not receiving OACs. The most common prescribed dose was a reduced dose for all DOACs. A substantial proportion of patients receiving the reduced dose did not fulfill dose reduction criteria (underdosing): apixaban, 25.1%; rivaroxaban, 26.3%; and edoxaban, 13.7%. Some patients received a lower off-label dose rather than the reduced dose: apixaban, 5.9%; rivaroxaban, 0.3%; edoxaban, 5.3%; and dabigatran, 13.6%. In multivariate analyses, advanced age, history of hemorrhage, paroxysmal AF, and antiplatelet drug use were significantly associated with no OAC. Advanced age, persistent or permanent AF, chronic kidney disease, and concomitant antiplatelet drugs were associated with warfarin rather than DOAC use. Conclusions: In the ANAFIE Registry, >90% of elderly Japanese AF patients received OAC therapy, mostly DOACs. Inappropriate low doses of DOACs that did not fulfill dose reduction criteria were prescribed in 20-30% of patients.