Utilization of Standard and Target-Specific Oral Anticoagulants Among Adults in the United Kingdom With Incident Atrial Fibrillation.

New oral anticoagulants (OACs) and updated risk stratification have the potential to improve the quality of care for patients with atrial fibrillation (AF). To describe the time from AF diagnosis to the initiation of an OAC, characteristics associated with treatment, and the incidence of switching OACs, we conducted this retrospective cohort study of 23,018 adults with incident AF receiving care between 2010 and 2014 in 647 primary care practices participating in the United Kingdom Clinical Practice Research Datalink. In patients with moderate to high stroke risk (CHA2DS2-VASc ≥ 2), the median time from diagnosis to OAC initiation decreased from 10 to 2 months. Among 980 at very low stroke risk (CHA2DS2-VASc = 0), 29% received OAC prescriptions after 90 days. Being prescribed an OAC was associated with a history of stroke or transient ischemic attack (relative risk 1.3); severe dementia or psychosis was most associated with not being prescribed an OAC (relative risk 0.3). After 1 year, the risk of OAC switching was higher for patients initiating dabigatran (19%) than warfarin (6%), rivaroxaban (8%), or apixaban (9%). The prescribing of OACs in moderate-to-high-risk patients in the United Kingdom increased annually; 1/3 of very low-risk patients were prescribed OACs contrary to guidance. In conclusion, future research should refine decision-making tools to minimize the unwanted effects of underutilization and overutilization of OACs.