Non–Vitamin K Antagonist Oral Anticoagulants in Elderly (≥85 years) Patients With Newly Diagnosed Atrial Fibrillation: Changing Clinical Practice and Outcomes for Stroke Prevention in a Nationwide Cohort Study

Objective: To investigate the influences of non–vitamin K antagonist oral anticoagulants (NOACs) on rates of initiations of oral anticoagulants (OACs) and outcomes among elderly patients with atrial fibrillation (AF). Methods: From January 1, 2009, to December 31, 2015, 33,539 newly-diagnosed AF patients older than 85 years old who survived more than 180 days after AF diagnosis were studied. Temporal trends regarding OAC initiation rates after incident AF were analyzed. The 1-year risks of ischemic stroke, intracranial hemorrhage, and mortality of incident AF patients diagnosed each year were compared with that of the year 2009. Results: Initiation rates of OACs after AF was newly diagnosed in the elderly significantly increased from 9.5% to 34.3%, mainly due to the introduction of NOACs (from 0% to 26.2%). Several clinical factors were associated with OACs underuse, including chronic obstructive pulmonary disease, abnormal renal function, anemia, and history of bleeding. Compared with year 2009 (incidence rate, 5.55%/year), the 1-year risk of ischemic stroke after AF diagnosis decreased in the era of NOACs (incidence rate, 4.20%/year; adjusted hazard ratio [aHR], 0.748 in year 2012; 4.39%/year, aHR, 0.789 in 2014; 2.75%/year; aHR, 0.513 in year 2015; all P<.01, except for year 2013, 4.80%/year [P=.07]). Also, the risks of mortality were lower in years 2012 to 2015, while the risk of ICH remained unchanged. Conclusion: Initiation rates of OACs after AF was newly diagnosed in the elderly significantly increased following the introduction of NOACs. A lower risk of ischemic stroke, mortality, and composite adverse events was observed, which was temporally associated with the increasing prescription rates of OACs.