Safety of new oral anticoagulants

Two linked papers (doi:10.1136/bmj.h1857, doi:10.1136/bmj.h1585) report additional evidence on the risks of gastrointestinal bleeding among patients taking the novel oral anticoagulants dabigatran and rivaroxaban.1 2 From a database of more than 100 million US adults, Abraham and colleagues identified almost 220 000 new users of dabigatran, rivaroxaban, or warfarin between November 2010 and September 2013.1 In their comparison of propensity score matched patients, the risk of gastrointestinal bleeding increased significantly with age for both new oral anticoagulants, relative to warfarin. By age 75, the risk of gastrointestinal bleeding associated with rivaroxaban exceeded that with warfarin, for patients with or without atrial fibrillation. Among patients taking dabigatran, the association between older age and higher risk was confined to those with atrial fibrillation, although the data included very few patients without atrial fibrillation taking this drug.

In a second study, Chang and colleagues found no significant differences in risk of gastrointestinal bleeding between the newer agents and warfarin in a propensity weighted analysis of 46 000 members of a commercial insurance plan who had new prescriptions for warfarin, dabigatran, or rivaroxaban between October 2010 and March 2012.2 …