Factors associated with non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with new-onset atrial fibrillation: Results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II (ORBIT-AF II).

Background: Several non-vitamin K antagonist oral anticoagulant (NOAC) alternatives to warfarin are available for stroke prevention in atrial fibrillation (AF). We aimed to describe the factors associated with selection of NOACs versus warfarin in patients with new onset AF.

Methods: The ORBIT-AF II study is a national, US, prospective, observational, cohort study of anticoagulation treatment in patients with AF receiving NOACs or warfarin in the United States from 2013 to 2016. We measured factors associated with oral anticoagulant selection in 4,670 patients recently diagnosed with AF.

Results: At baseline, 1,169 (25%) patients were started on warfarin and 3,501 (75%) on NOACs: of these latter, 259 (6%) were started on dabigatran, 1858 (40%) on rivaroxaban, and 1384 (30%) on apixaban. Those receiving NOACs were slightly younger patients (median age 71 vs 72, P<.0001); were less likely to have prior stroke (5.3% vs 8.6%; P<.0001) or prior bleeding (2.7% vs 4.4%; P=.005); had better kidney function (mean estimated glomerular filtration rate 91 mL/min vs 80 mL/min, P<.0001); and had fewer patients at high stroke risk (CHADS-VASc score [Congestive heart failure, Hypertension, Age ≥75years, Diabetes mellitus, Prior stroke, transient ischemic attack {TIA}, or thromboembolism,Vascular disease, Age 65-74years, Sex category {female}] ≥2 in 86% vs 93%; P<.0001). In multivariable analysis, factors associated with NOAC selection versus warfarin included renal function, prior stroke or valve replacement, rhythm control AF management strategy, treatment by a cardiologist, and higher patient education level.

Conclusions: In contemporary clinical practice, up to three-fourths of patients with new-onset AF are now initially treated with a NOAC for stroke prevention. Those selected for NOAC treatment had lower stroke and bleeding risk profiles, were more likely treated by cardiologists, and had higher socioeconomic status.

Trial Registration: clinicaltrials.gov Identifier: NCT01701817.