Influence of Direct Oral Anticoagulants on Rates of Oral Anticoagulation for Atrial Fibrillation

Abstract

Background: Oral anticoagulation (OAC) with warfarin is underused for atrial fibrillation (AF). The availability of direct oral anticoagulants (DOACs) may improve overall OAC rates in AF patients, but a large-scale evaluation of their effects has not been conducted.

Objectives: This study assessed the effect of DOAC availability on overall OAC rates for nonvalvular AF.

Methods: Between April 1, 2008 and September 30, 2014, we identified 655,000 patients with nonvalvular AF and a CHA₂DS₂-VASc score of >1 in the National Cardiovascular Data Registry PINNACLE registry. Temporal trends in overall OAC and individual warfarin and DOAC use were analyzed. Multivariable hierarchical logistic regression identified patient factors associated with OAC and DOAC use. Practice variation of OAC and DOAC use was also assessed.

Results: Overall OAC rates increased from 52.4% to 60.7% among eligible AF patients (p for trend <0.01). Warfarin use decreased from 52.4% to 34.8% (p for trend <0.01), and DOAC use increased from 0% to 25.8% (p for trend <0.01). An increasing CHA₂DS₂-VASc score was associated with higher OAC use (odds ratio [OR]: 1.06; 95% confidence interval [CI]: 1.05 to 1.07), but with lower DOAC use (OR: 0.97; 95% CI: 0.96 to 0.98). Significant practice variation was present in OAC use (median odds ratio [MOR]: 1.52; 95% CI: 1.45 to 1.57) and in DOAC use (MOR: 3.58; 95% CI: 3.05 to 4.13).

Conclusions: Introduction of DOACs in routine practice was associated with improved rates of overall OAC use for AF, but significant gaps remain. In addition, there is significant practice-level variation in OAC and DOAC use.

Keywords: atrial fibrillation; direct oral anticoagulants; oral anticoagulation.