Abstract 17770: Reduced-Dose Non-Vitamin K Antagonist Oral Anticoagulants Are More Frequently Prescribed to Women but May Not Be Responsible for Poorer Outcomes
Introduction: Over the past few years, four non-vitamin K antagonist oral anticoagulants (NOACs) have been widely adopted for stroke prevention in atrial fibrillation (AF). Early non-trial data suggested that women treated with dabigatran were more frequently prescribed with the reduced dose instead of the standard dose. This observation raised concerns that women may receive suboptimal NOAC treatment.
Hypothesis: Women are more likely than men to receive reduced-dose NOACs, but this prescribing pattern may reflect higher risk profile in women that justifies the use of a reduced dose.
Methods: Using a large U.S. commercial insurance database, we identified 39,539 patients with AF, among whom apixaban, dabigatran, edoxaban or rivaroxaban was initiated between 10/1/2010 and 6/30/2015. We performed one-to-one propensity score matching between patients receiving reduced doses and patients receiving standard doses, in women and men separately. Cox proportional hazards regression was used to assess the relationship between the use of reduced doses and the risks of stroke and bleeding.
Results: Women were more likely to receive reduced-dose NOACs (adjusted odds ratio 1.67 [1.56-1.77], p<0.001). The event rate of stroke was 1.50%/yr in women and 0.89%/yr in men (adjusted Hazard ratio [HR] 1.44 [1.11-1.86], p=0.01). The event rate of major bleeding was 3.70%/yr in women and 2.39%/yr in men (HR: 1.21 [1.03-1.42], p=0.02). In the propensity-score matched cohort of women, those who received reduced-dose NOACs had similar risk of stroke (HR 1.29 [0.78-2.15]) and major bleeding (HR 1.05 [0.78-1.41]) in comparison to women who received standard doses. In the propensity-score matched cohort of men, those who received reduced-dose NOACs had similar risk of stroke (Hazard ratio [HR] 1.71 [0.74-3.96]) and major bleeding (HR 1.16 [0.81-1.67]) in comparison to men who received standard doses.
Conclusions: In routine clinical practice, women with AF are more likely to be prescribed with reduced-dose NOACs. Women also have higher risks of both stroke and bleeding on NOACs than men. However, there is no evidence to suggest that the use of reduced doses contributes to the poorer outcome in women, which is presumably a reflection of greater baseline risk.
Author Disclosures: X. Yao: None. B.J. Gersh: Consultant/Advisory Board; Modest; Medtronic Inc, Baxter Healthcare Corporation, Cardiovascular Research Foundation, St. Jude Medical, Ortho-McNeil-Janssen Pharmaceuticals, Teva Pharmaceuticals, Boston Scientific, Pfizer. N.D. Shah: None. L.R. Sangaralingham: None. P.A. Noseworthy: None.
- © 2016 by American Heart Association, Inc.