['Although several non-vitamin K oral anticoagulants have been developed to prevent cardiogenic thrombosis, the status of hemorrhagic complications in the clinical setting among Asian populations, including Japan, remains unclear. We conducted this retrospective cohort study to clarify the current status of hemorrhagic events during antithrombotic therapy with non-vitamin K oral anticoagulants, with particular focus on gastrointestinal bleeding.', 'Medical charts of 475 patients prescribed dabigatran, rivaroxaban, or apixaban between April 2011 and September 2014 were reviewed to examine whether any hemorrhagic events occurred, compared with 135 patients who received warfarin between April 2009 and March 2011.', 'Incidences of total and actionable hemorrhage in patient taking non-vitamin K oral anticoagulants were 13.8% per year and 4.6% per year, respectively, showing no significant differences from those in warfarin users (9.3% per year and 5.0% per year, respectively). In addition, actionable gastrointestinal hemorrhage occurred at similar rates in non-vitamin K oral anticoagulants users (2.1% per year) and warfarin users (1.5% per year). Most hemorrhages were from the lower gastrointestinal tract, and considerable events involved perianal bleeding. Multiple regression analysis showed that age, concomitant dual antiplatelet therapy, and concomitant nonsteroidal anti-inflammatory drug therapy were significant factors related to actionable gastrointestinal bleeding.'] Is gastrointestinal bleeding risk of non-vitamin K oral anticoagulants similar to warfarin - a Japanese retrospective cohort study?