Abstract 18371: Higher Treatment Persistence of Non-Vitamin K Antagonist Oral Anticoagulants than Vitamin K Antagonists at 1 Year in Non-Valvular Atrial Fibrillation in Real-World Practice

Abstract

Introduction: Oral anticoagulants (OAC) are under-utilised in atrial fibrillation (AF). Even patients prescribed an OAC may stop taking the drug soon after treatment initiation, particularly with Vitamin K Antagonists (VKA). The Non-VKA OAC (NOAC) drugs offer greater ease of use, and persistence is likely to be higher. Aim: To determine persistence on treatment in the first year after inception of NOACs and VKA in incident AF in real-world clinical practice. Methods: We studied 24,467 OAC-naïve patients with incident non-valvular AF diagnosed between Jan 2011-Feb 2014, mean age 73.9 ± 12.5, 45.6% female, in a very large UK primary care database (Clinical Practice Research Datalink, CRPD), with full linkage to medication use. Follow up was for a mean of 1.2 ± 0.9 years. The proportion of OAC initiation in the 90 days after first-time AF and of those remaining on OAC one year after initiation were estimated using competing risk survival analyses censoring for use of alternative OAC. Results: NOAC drugs prescribed included Rivaroxaban, Dabigatran and Apixaban. Overall, 12,579 (51.4%) were commenced on an OAC: 11,888 on VKA and 691 on NOAC, within 90 days after incident AF. Amongst all OAC users, the proportion taking NOAC increased from 0.3% in 2011 to 12.3% in 2014. Persistence, defined as the proportion still taking the OAC after one year, declined over the 12 months to 54.3% for VKA and 80.7% for NOAC (Table). Persistence was significantly greater for NOAC than VKA at all time points. Conclusions: There is a progressive fall in VKA use amongst OAC naïve patients with AF in real-world practice to only 54% at 1 year. This contributes to under-utilisation of anticoagulation in AF and would result in an increased rate of stroke. Persistence was significantly improved with NOACs compared to VKA, and this factor alone could lead to reduced stroke burden with increasing uptake of the NOACs.