The effect of sex on the efficacy and safety of dual antithrombotic therapy with dabigatran versus triple therapy with warfarin after PCI in patients with atrial fibrillation (a RE-DUAL PCI subgroup analysis and comparison to other dual antithrombotic therapy trials)

Clin Cardiol. 2021 May 27. doi: 10.1002/clc.23649. Online ahead of print.


Background: The RE-DUAL PCI trial demonstrated that in patients with nonvalvular atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI), dual therapy with dabigatran and a P2Y12 inhibitor, either clopidogrel or ticagrelor, reduced the risk of bleeding without an increased risk of thromboembolic events as compared to triple therapy with warfarin in addition to a P2Y12 inhibitor and aspirin. What remains unclear is whether this effect is consistent between males and females undergoing PCI.

Hypothesis: The reduction in risk of bleeding without increased risk of thromboembolic events with dual therapy with dabigatran and a P2Y12 inhibitor in comparison to triple therapy with warfarin, a P2Y12 inhibitor and aspirin is consistent in females and males.

Methods: The primary safety endpoint was the first International Society on Thrombosis and Hemostasis (ISTH) major bleeding event (MBE) or clinically relevant non-major bleeding event (CRNMBE). The efficacy endpoint was the composite of death, thromboembolic event (stroke, myocardial infarction, and systemic embolism) or unplanned revascularization. Cox proportional hazard regression analyses were applied to calculate corresponding hazard ratios and interaction p values for each endpoint.

Results: A total of 655 women and 2070 men were enrolled. The risk of major or CRNM bleeding was lower with both dabigatran 110 mg dual therapy and dabigatran 150 mg dual therapy compared with warfarin triple therapy in female and male patients (for 110 mg: females: HR 0.69, 95% CI 0.47-1.01, males: HR 0.46, 95% CI 0.37-0.59, interaction p value: 0.084 and for 150 mg: females HR 0.74, 95% CI 0.48-1.16, males HR 0.71, 95% CI 0.56-0.90, interaction p value: 0.83). There was also no detectable difference in the composite efficacy endpoint of death, thromboembolic events or unplanned revascularization between dabigatran dual therapy and warfarin triple therapy, with no statistically significant interaction between sex and treatment (interaction p values: 0.73 and 0.72, respectively).

Conclusions: Consistent with the overall study results, the risk of bleeding was lower with dabigatran 110 mg and 150 mg dual therapy compared with warfarin triple therapy, and risk of thromboembolic events was comparable with warfarin triple therapy independent of the patient's sex.

Keywords: dual antithrombotic therapy; sex differences; triple therapy.