Warfarin Associated With Poorer Outcomes Compared With New Oral Anticoagulants

Despite the fact that warfarin is more easily reversible, bleeding complications with the therapy are associated with longer stays in the hospital and higher mortality than dabigatran and rivaroxaban, according to a poster presented at the American Heart Association Scientific Sessions.

The researchers analyzed claims of adults with atrial fibrillation who were hospitalized for bleeding after starting warfarin, dabigatran, or rivaroxaban. Outcomes were length of stay in the hospital, intensive care unit (ICU) admission, length of ICU stay, and all-cause mortality. Patients treated with warfarin had worse outcomes than those treated with new oral anticoagulants.

“Little is known about the relative outcomes of bleeding complications during warfarin therapy compared to bleeding complications during treatment with dabigatran or rivaroxaban,” the authors wrote.

Warfarin users were older and had more comorbidities than dabigatran or rivaroxaban users, the researchers found. However, after adjusting, warfarin was still associated with a 2.2 mean day increase in hospital stay compared with dabigatran and a 3.1 mean day increase compared with rivaroxaban.

"Our results are completely the opposite of what we thought we would find when we did this study," Blake Charlton, MD, told Medpage Today. "We were really, really surprised by these findings."

In addition, after more than 3 years follow up, the researchers found a 17% adjusted mortality in the warfarin group compared with 13% for the dabigatran group, and 6% in the rivaroxaban group. However, 30- and 90-day mortality rates did not differ significantly.

The researchers also analyzed subgroups: patients with chronic kidney disease, heart failure, more than 7 comorbidities, hemorrhagic stroke, major gastrointestinal bleed, patients older than 75 years, patients without ICU admission, and patients restarting anticoagulant after discharge. They found that in every subgroup, warfarin was associated with longer hospitalization.

“However, because patients treated with newer oral anticoagulants are younger and healthier, randomized trials are necessary to better understand these unexpected differences in bleeding-related outcomes,” the authors concluded.