In-hospital mortality for patients with atrial fibrillation who experienced intracranial bleeding was similar whether they were treated with dabigatran or warfarin in a study published online July 3 in Stroke. The findings may help physicians and patients who are choosing between the two types of anticoagulants.
Dabigatran (Pradaxa, Boehringer Ingelheim) is an FDA-approved direct thrombin inhibitor that is used to reduce the risk of stroke in patients with atrial fibrillation. Like other new oral anticoagulants, dabigatran offers physicians and patients an alternative to warfarin, which requires monitoring. But unlike warfarin, the newer drugs lack an antidote to reverse their effect in the event of acute bleeding.
Alvaro Alonso, MD, PhD, of the School of Public Health at the University of Minnesota in Minneapolis, and colleagues devised a study to evaluate in-hospital mortality in a less controlled setting than was seen in clinical trials. For their assessment, they used claims data from the Truven Health MarketScan Commercial Claims and Encounter Database and the Medicare Supplemental Coordination of Benefits database between 2009 and 2012.
The databases allowed them to access outpatient pharmaceutical data on anticoagulant use and identify patients with a prior history of atrial fibrillation who were admitted to a hospital for intracranial bleeding. The primary outcome was in-hospital mortality.
They found 2,391 cases with a primary diagnosis of intracranial bleeding in patients with atrial fibrillation (2,290 on warfarin, 101 on dabigatran). There were no significant differences in mean age, sex and mean risk of ischemic stroke. The dabigatran group had a higher risk of hemorrhage and were more likely to have a history of gastrointestinal bleeding.
The warfarin group had an in-hospital mortality rate of 22 percent vs. 20 percent in the dabigatran group. After adjusting for clinical covariates, Alonso et al found no association between current use of dabigatran compared with warfarin for mortality.
The researchers noted that men in the dabigatran group had a lower bleeding risk than men in the warfarin group, while women in the warfarin group had a lower bleeding risk than women in the dabigatran group.
“No obvious explanation can be provided for this difference,” they wrote. “It is possible that metabolism of dabigatran may differ by sex; alternatively, this observation could also be because of chance.”
They proposed that their findings may help physicians and patients make informed decisions as they weigh the pros and cons of dabigatran and warfarin therapy.