Is There a Greater Bleeding Risk with Dabigatran Than Warfarin?

A retrospective analysis connects the oral anticoagulant Dabigatran to greater bleeding risks than warfarin in older patients with atrial fibrillation.

Using Medicare data on adults who were diagnosed with atrial fibrillation in 2010 and 2011, lead study author Inmaculada Hernandez, PharmD, a PhD student at the University of Pittsburgh Graduate School of Public Health, and colleagues compared outcomes in about 1,300 patients who filled prescriptions for dabigatran, and 8,100 patients who filled prescriptions for warfarin.
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Over a follow-up period of roughly 6 months to 7.5 months, the authors found that dabigatran users had significantly higher bleeding risks than warfarin users, in terms of any bleeding (33% compared to 27%), major bleeding (9% versus 6%), and gastrointestinal bleeding (17% compared to 10%). In addition, intracranial hemorrhage occurred more often with warfarin, at a rate of 0.6% compared to 1.8%.

In African-American patients as well as those with chronic kidney disease, the risk for major bleeding with dabigatran was especially high, while the higher risk for intracranial bleeding with warfarin was limited to those patients age 75 and older, who note that dabigatran should be prescribed with caution in high-risk patients, “before more evidence is available.”

In terms of the prescription and management of blood thinners in this patient population, the implications of this analysis are twofold for primary care practitioners, says Hernandez.

First, patients on dabigatran should be warned about the high risk of gastrointestinal bleeding and explained how to detect it, i.e., by checking stool color, so that it can be stopped promptly,” says Hernandez.

Secondly, patients age 75 and up who are at high risk for intracranial bleeding “are probably the subgroup in which dabigatran is most likely to have a more favorable profile, in terms of bleeding, than warfarin, because of the high decrease in the risk of intracranial bleeding (90%),” says Hernandez.

“Given the individual patient characteristics and risk factors for 2 types of bleeding, doctors should discuss with these patients the trade-off between risk of gastrointestinal bleeding with dabigatran and risk of intracranial bleeding with warfarin.”

—Mark McGraw

Reference

Hernandez I, Hyon-Baik S, et al. Risk of Bleeding With Dabigatran in Atrial Fibrillation. JAMA Intern Med. 2014.