DOACs May be More Effective than Warfarin for Valvular AFib

Ghadeer Dawwas, PhD

A new study from the Perelman School of Medicine at the University of Pennsylvania found patients with valvular atrial fibrillation (AF) using direct oral anticoagulants (DOACs) had lower risks for ischemic stroke or systemic embolism and major bleeding than their counterparts using warfarin.

A retrospective, propensity score-matched analysis using claims data, results of the study provide insight into real-world prescribing practices and outcomes among patients with valvular AF.

“These findings have important clinical implications for patients with valvular AF who are at risk for poor outcomes; DOACs provide treatment options in patients who receive suboptimal benefits from warfarin therapy,” wrote investigators.

With a limited amount of data available related to the efficacy and safety of initiating therapy with DOACs versus with warfarin in patients with valvular AF, a team led by Ghadeer Dawwas, PhD, designed the current study to examine the topic using the OptumInsight Clinformatics database. Using a time frame from January 2010 through June 2019, investigators performed a search of patients who had at least 1 prescription for a DOAC or warfarin and this search returned data on 56,336 propensity score-matched patients meeting inclusion criteria.

For inclusion in the analysis, patients needed to have data available for 12 months preceding first prescription, be at least 18 years of age or older, and could not have a history of end-stage renal disease, knee or hip replacement, or stroke and systemic embolism. The primary efficacy outcome of interest for the study was a composite of ischemic stroke or systemic embolism. The primary safety outcome of interest was major bleeding, which investigators noted was a composite of gastrointestinal or intracranial bleeding.

Among the final study cohort, 28,168 were considered new users of DOACs and 28,168 were considered new users of warfarin. Of the 28,168 users of DOACS, investigators found 19,136 used apixaban, 12,851 used rivaroxaban, and 3535 used dabigatran.

Upon analysis, results indicated patients who received DOACs had a lower risk for ischemic stroke or systemic embolism (HR, 0.64; 95% CI, 0.59-0.70) compared to those who received warfarin. Additionally, DOACs were also associated with a lower risk of major bleeding events (HR, 0.67; 95% CI, 0.63-0.72).

Further analysis indicated efficacy and safety outcomes remained consistent for apixaban ([HR, 0.54; 95% CI, 0.47-0.61] and [HR, 0.52; 95% CI, 0.47-0.57], respectively) and rivaroxaban ([HR, 0.74; 95% CI, 0.64-0.86] and [HR, 0.87; 95% CI, 0.79-0.96], respectively). However, with dabigatran, results indicated consistency was only seen for the safety outcome (HR, 0.81; 95% CI, 0.68-0.97) and not the efficacy outcome (HR, 1.03; 95% CI, 0.81-1.31).

Investigators noted their study was limited by certain factors. These included an inability to track long-term outcomes among these patients and an inability to ascertain disease severity of patients.

“Despite these limitations, these real-world data suggest that patients with valvular AF who were new users of DOACs had a lower rate of ischemic stroke or SE and major bleeding than new users of warfarin. These data should guide anticoagulant choices for patients with valvular AF,” wrote investigators.

This study, “Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients With Valvular Atrial Fibrillation,” was published in the Annals of Internal Medicine.