Rivaroxaban is associated with significantly more intra- and extracranial bleeding than is dabigatran in older patients who have nonvalvular atrial fibrillation, according to a report published online Oct. 3 in JAMA Internal Medicine.
This is the principal finding of a retrospective cohort study – the only study to directly compare the two oral non–vitamin-K-antagonists – that involved more than 118,000 patients who initiated anticoagulation treatment during a 2.5-year period. The Centers for Medicare & Medicaid Services and the Food and Drug Administration jointly conducted the study.
During the study period, rivaroxaban was used 2-3 times more often than was dabigatran in AF patients in the United States, “perhaps partly because of prescriber misperceptions about bleeding risks with dabigatran, arising from FDA receipt of a large number of postmarketing case reports following its approval. Ironically, we [now find] substantially higher bleeding risks with use of rivaroxaban than dabigatran,” said David J. Graham, MD, of the Office of Surveillance and Epidemiology, Center for Drug Evaluation and Research, FDA, Silver Spring, Md., and his associates.
The researchers assessed Medicare beneficiaries who initiated standard oral doses of rivaroxaban (66,651 patients) or dabigatran (52,240 patients) and were followed for a mean of 110 days.
The primary outcome measure – a composite of thromboembolic stroke, intracranial hemorrhage, major extracranial bleeding events including GI bleeding, and mortality – occurred in significantly more patients taking rivaroxaban than in those taking dabigatran. When the individual components of this composite outcome were considered, rivaroxaban was associated with significant increases in intracranial hemorrhage (HR, 1.65), major extracranial bleeding (HR, 1.48), and major GI bleeding (HR, 1.40); a nonsignificant decrease in thromboembolic stroke (HR, 0.81); and a nonsignificant increase in mortality (HR, 1.15).
In a further analysis of the data, rivaroxaban was linked to 2.3 excess cases of intracranial hemorrhage, 13 excess cases of major extracranial bleeding, 9.4 excess cases of major GI bleeding, and 3.1 excess deaths per 1,000 person-years of treatment. In addition, rivaroxaban was associated with a significantly increased risk of death in two subgroups of patients: those aged 75 and older and those whose CHADS-2 scores indicated higher bleeding risk, Dr. Graham and his associates said (JAMA Intern. Med. 2016 Oct 3. doi: 10.1001/jamainternmed.2016.5954).
Of note, “the net increase in intracranial hemorrhage, the outcome with the highest case fatality rate, exceeded the net reduction in thromboembolic stroke” with rivaroxaban treatment, they added.