Clinical outcomes of the real-world Asian nonvalvular atrial fibrillation (NVAF) patients treated with DOAC and the incremental bleeding risk of add-on antiplatelet therapy to direct oral anticoagulants (DOACs) are still to be investigated. We conducted a single-center prospective observational registry of NVAF patients treated with DOACs: the DIRECT registry (UMIN000033283). All patients with NVAF (N = 2216) who were users of dabigatran (N = 648), rivaroxaban (N = 538), apixaban (N = 599), or edoxaban (N = 431) from June 2011 to November 2017 were enrolled (71.6 ± 10.8 years, 36.4% female, follow-up duration: 407.2 ± 388.3 days). No add-on antiplatelet agent was prescribed to 1,739 patients, while single and dual antiplatelet therapy (SAPT and DAPT) in combination with DOAC were prescribed to 411 and 66 patients, respectively. The primary safety endpoint was any bleeding which was defined as a composite of major bleeding according to the International Society on Thrombosis and Hemostasis criteria and clinically relevant non-major bleeding. Patients treated with add-on antiplatelet agents irrespective of SAPT or DAPT had a higher any-bleeding risk than those without (hazard ratio: 1.42; 95% confidence interval 1.16-1.74, p = 0.001). Multivariate adjusted hazard of add-on antiplatelet therapy was not statistically significant (hazard ratio: 1.20; 95% confidence interval 0.94-1.53, p = 0.147). In conclusion, NVAF patients treated with antiplatelet agents and DOAC had a significantly higher bleeding risk than those using DOAC only. However, after adjustment of patients' background, add-on antiplatelet therapy to DOAC itself did not influence to a bleeding risk.
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