CHICAGO – Apixaban outperformed two other direct-acting oral anticoagulants, dabigatran and rivaroxaban, by preventing more thrombotic events and not causing as many major bleeds in patients with atrial fibrillation who were at least 80 years old.
The findings come from an analysis of insurance claims data from more than 50,000 U.S. patients – the largest observational study to date to compare these three direct-acting oral anticoagulants (DOACs) in octogenarians with nonvalvular atrial fibrillation, Steven B. Deitelzweig, MD, said at the American Heart Association scientific sessions.
“The results may help clinicians evaluate the risk-benefit ratio of the DOACs” in this population, said Dr. Deitelzweig, vice president for medical affairs at Ochsner Medical Center in New Orleans.
He noted that the results were consistent with prior reports from observational data and registries, as well as the results in a recent analysis commissioned by the Agency for Healthcare Research and Quality. “We see a consistent message that apixaban always has less risk for major bleeding, and at least comparable efficacy” when compared with other DOACs, he said in a video interview.
And for the foreseeable future, this sort of data will need to suffice for clinicians trying to decide which DOAC to use because “I know of no head-to-head trials, nor do I anticipate any head-to-head trials” that could provide a more definitive comparison of the DOACs, Dr. Deitelzweig said.
The data came from a large number of patients – about 38% of the U.S. population – which boosts the generalizability of the finding. “I think our data are useful” for helping to make treatment decisions, he concluded.
The analysis he reported came from the ARISTOPHANES (Anticoagulants for Reduction in Stroke: Observational Pooled Analysis on Health Outcomes and Experience of Patients) study, which pooled U.S. insurance claims data from several sources. For the octogenarian study, Dr. Deitelzweig and his associates used data from about 123 million U.S. residents collected between January 2012 and September 2015 by Medicare and three different commercial insurance databases. The overall level of beneficiary overlap between these four data sources was less than 0.5%.
The researchers identified patients with nonvalvular atrial fibrillation who started anticoagulant treatment with a DOAC and were at least 80 years old. This included 19,752 patients started on apixaban (Eliquis), 6,741 started on dabigatran (Pradaxa), and 27,217 started on rivaroxaban (Xarelto). A majority of the patients were at least 84 years old.
The analysis used propensity-score matching to compare similar patients and to minimize the impact of potentially confounding differences among the patients in each treatment subgroup. During a median follow-up of 7-9 months, the incidence of stroke or systemic embolism was 35% lower in the apixaban-treated patients, compared with those who received dabigatran, and 28% lower in the apixaban patients, compared with those treated with rivaroxaban, both statistically significant differences, Dr. Deitelzweig reported. The incidence of major bleeding episodes was 40% lower with apixaban than with dabigatran and 50% lower with apixaban, compared with rivaroxaban, also statistically significant differences.
When the analysis compared dabigatran with rivaroxaban it showed no statistically significant difference for the efficacy endpoint, but dabigatran produced 23% fewer major bleeds than rivaroxaban, a statistically significant difference.
These findings jibed with a recently published analysis from Dr. Deitelzweig and his associates that used data from all adults with nonvalvular atrial fibrillation started on an oral anticoagulant in an expanded ARISTOPHANES database for 2012-2015 that included more than 180 million U.S. beneficiaries. After propensity-score matching, this created subgroups of about 58,000 patients started on apixaban, nearly 27,000 started on dabigatran, and more than 83,000 started on rivaroxaban. The patients averaged about 73 years old. Again, with about 7-9 months of follow-up, very similar outcomes occurred. Patients on apixaban had significantly fewer strokes and systemic embolic events as well as significantly fewer major bleeds compared with patients treated with one of the other DOACs (Stroke. 2018 Dec;49:2933-44).
The study was funded by Bristol-Myers Squibb and Pfizer, the companies that market apixaban (Eliquis). Dr. Deitelzweig is a consultant to and speaker on behalf of Bristol-Myers Squibb and Pfizer. He is also a consultant to or speaker on behalf of Boehringer Ingelheim, Daiichi-Sankyo, Janssen, and Portola Pharmaceuticals.