DOACs show better safety and effectiveness versus warfarin in patients with valvular AF

Ghadeer Dawwas

Patients with valvular atrial fibrillation (AF) who were new users of direct oral anticoagulants (DOACs) were at lower risk for ischaemic stroke or systemic embolism and major bleeding than new users of warfarin, an analysis published in the Annals of Internal Medicine has found.

These data may be used to guide risk–benefit discussions regarding anticoagulant choices for patients with valvular AF, authors of the paper have suggested.

Warfarin has been the mainstay therapy to prevent stroke, but drawbacks include a narrow therapeutic window, dose-response variability, and many interactions with drugs and food, the study’s authors note.

Randomised clinical trials have demonstrated that DOACs have similar or superior antithrombotic effects to warfarin and lower bleeding risk, while DOACs are increasingly being used in place of warfarin, evidence about their effectiveness and safety in patients with valvular AF remains limited.

Led by study author Ghadeer Dawwas (University of Pennsylvania, Philadelphia, USA), researchers from the Perelman School of Medicine at the University of Pennsylvania used data from a practice-based commercial healthcare database between January 2010 and June 2019 to assess the safety and effectiveness of DOAC versus warfarin for adults with valvular AF who were newly prescribed either medication.

The primary effectiveness outcome was a composite of ischaemic stroke or systemic embolism, while the primary safety outcome was a composite of intracranial or gastrointestinal bleeding.

Among a total of 56,336 patients with valvular AF matched on propensity score, the study authors report that the use of DOACs (vs. warfarin) was associated with lower risk for ischaemic stroke or systemic embolism (hazard ratio [HR], 0.64 [95% CI, 0.59 to 0.70]) and major bleeding events (HR, 0.67 [CI, 0.63 to 0.72]).

The results for the effectiveness and safety outcomes remained consistent for apixaban (HRs, 0.54 [CI, 0.47 to 0.61] and 0.52 [CI, 0.47 to 0.57], respectively) and rivaroxaban (HRs, 0.74 [CI, 0.64 to 0.86] and 0.87 [CI, 0.79 to 0.96], respectively); with dabigatran, results were consistent for the major bleeding outcome (HR, 0.81 [CI, 0.68 to 0.97]) but not for effectiveness (HR, 1.03 [CI, 0.81 to 1.31]).

The study’s authors note that the findings are limited by the study’s relatively short follow-up, as well as an inability to ascertain disease severity.


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