Abstract
It is not understood if dabigatran or rivaroxaban are superior to antiplatelet agents (AA) for safety outcomes in Asians with non-valvular atrial fibrillation (NVAF). In this study we evaluated the bleeding risk of dabigatran, rivaroxaban, warfarin and AA in Asians with NVAF. This national retrospective cohort study analyzed 6,600, 3,167, 5,338 and 8,238 consecutive NVAF patients taking dabigatran, rivaroxaban, warfarin or AAs (including aspirin, clopidogrel or ticlopidine), respectively, from June 1, 2012 to December 31, 2013. Propensity-score weighting was used to balance covariates across study groups. Patients were followed until the first occurrence of any bleeding outcome or the end of the study. The CHA2DS2-VASc scores were 4.1±1.6, 4.1±1.6, 3.3±1.8 and 2.4±1.6 for the dabigatran, rivaroxaban, warfarin, and AA groups, respectively. There were 5,822 (88.2%) and 164 (5.2%) patients taking low dose dabigatran and rivaroxaban, respectively. Hazard ratios (95% confidence intervals) for dabigatran, rivaroxaban, or warfarin versus AA were: intracranial hemorrhage, 0.36 (0.23-0.57;PP=0.0037) and 1.34 (0.89-2.02;P=0.1664); gastrointestinal bleeding, 0.44 (0.32-0.59;PP=0.0189); and all hospitalized major bleeding, 0.41 (0.32-0.53;PP=0.0644) and 0.90 (0.70-1.16;P=0.4130) after adjustment. The risk reduction of all major bleeding for dabigatran versus AA persisted on subgroup analysis. In conclusion, we observed that dabiagtran was associated with a lower risk of all major bleeding in Asians with NVAF, whereas rivaroxaban had a similar risk of all major bleeding compared with antiplatelet agents after adjustment of comorbidities.
Highlights
Randomized trials have shown that warfarin significantly decreased the risk of thromboembolic events by 62% in patients with atrial fibrillation (AF), vitamin K antagonists (VKAs) remained underutilized in real world clinical practice. [1,2,3] There is a higher risk of intracranial hemorrhage (ICH) and other major bleeding events in Asians taking warfarin, compared to non-Asians. [4, 5] Data from a real-world www.impactjournals.com/oncotarget registry study showed that more than 65% of Asian patients on warfarin had a markedly low (16.7%) time in therapeutic range (TTR)
There are no studies currently which directly compared the safety outcomes in AF patients treated with other nonvitamin K antagonist oral anticoagulants (NOACs), versus those treated with aspirin
Subgroup analysis confirmed that dabigatran was associated with a lower risk of major bleeding compared with antiplatelet agents (AA) in most subgroups, whereas warfarin and rivaroxaban were associated with a similar risk of major bleeding compared with AA in most subgroups
Summary
Randomized trials have shown that warfarin significantly decreased the risk of thromboembolic events by 62% in patients with atrial fibrillation (AF), vitamin K antagonists (VKAs) remained underutilized in real world clinical practice. [1,2,3] There is a higher risk of intracranial hemorrhage (ICH) and other major bleeding events in Asians taking warfarin, compared to non-Asians. [4, 5] Data from a real-world www.impactjournals.com/oncotarget registry study showed that more than 65% of Asian patients on warfarin had a markedly low (16.7%) time in therapeutic range (TTR). [6] Aspirin reduces the risk of stroke in AF patients by about 20% and is commonly used in AF patients for whom warfarin therapy is unsuitable. [1] aspirin is not as efficacious as warfarin in reducing the thromboembolic risk, it may be a more convenient choice than warfarin in certain patient populations, and may be prescribed as an alternative to warfarin for stroke prevention especially in Asia.The AVEROOSES trial reported that apixaban was non-inferior to aspirin for the risk of major bleeding (1.4%/year versus 1.2%/year, respectively) in AF patients. [7] These data suggested that apixaban is an attractive alternative to aspirin for stroke prevention in AF patients unsuitable for warfarin. The AVEROOSES trial reported that apixaban was non-inferior to aspirin for the risk of major bleeding (1.4%/year versus 1.2%/year, respectively) in AF patients. There are no studies currently which directly compared the safety outcomes in AF patients treated with other nonvitamin K antagonist oral anticoagulants (NOACs), (e.g. dabigatran, edoxaban or rivaroxaban) versus those treated with aspirin. It is unclear whether dabigatran or rivaroxaban is superior to antiplatelet agents (AA) (including aspirin, clopidogrel, or ticlopidine) for safety outcomes, in Asians with AF. In this study we evaluated the bleeding risk associated with dabigatran, rivaroxaban, warfarin compared to AA therapy in Asians with non-valvular AF
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