In patients on direct oral anticoagulants (DOACs) for atrial fibrillation (AF) and venous thromboembolism (VTE), treatment with apixaban resulted in less bleeding and was associated with lower rates of mortality when compared with rivaroxaban and warfarin. This is according to study findings presented at the 65th ASH Annual Meeting and Exposition.
Apixaban and rivaroxaban remain the most used DOACs for AF and VTE and have been studied against warfarin in several landmark clinical trials, according to lead study author Jordan K. Schaefer, MD, of the University of Michigan in Ann Arbor, who presented the research. “However, there are limited direct comparative efficacy studies,” he said, “and there’s limited data in non-trial settings.”
In a non-trial-based study cohort, Dr. Schaefer and colleagues evaluated patient characteristics and outcomes associated with the use of apixaban, rivaroxaban, and warfarin.
The retrospective, registry-based study examined data from 13,435 patients receiving DOACs for VTE or non-valvular AF, or both, across six anticoagulation clinics in Michigan. The overall cohort included 3,536 patients on apixaban, 1,395 patients on rivaroxaban, and 8,504 patients on warfarin.
The mean age of the study population was 66.7 years, and roughly half (51.1%) identified as male. The mean follow-up was 28.2 months. Cohorts were propensity matched (apixaban vs. warfarin [1:1], rivaroxaban vs. warfarin [1:3], and apixaban vs. rivaroxaban [1:1]) using 1:1-3:1 matching ratios.
Among patients taking apixaban versus warfarin, rates of any bleeding were similar, but major bleeding was higher with warfarin
The rates of emergency room (ER) visits and hospitalizations for bleeding were higher in patients receiving warfarin. Patient mortality was also higher on warfarin (3.7 vs. 4.4 deaths/100 patient years; p=0.027).
When compared with warfarin, rates of any bleeding and major bleeding were higher with rivaroxaban (37.9 vs. 24.9 events/100 patient years, p<0.001; 4.7 vs. 3.6 events/100 patient years, p=0.041). A higher rate of the thrombotic subtype of other thrombosis was associated with rivaroxaban (1.0 vs. 0.3 events/100 patient years; p=0.002). Patients receiving rivaroxaban and warfarin had similar rates of ER visits, hospitalizations, and mortality.
Respective rates of any bleeding and major bleeding were also higher with rivaroxaban when compared with apixaban (37.9 vs. 25.7 events/100 patient years, p<0.001; 4.7 vs. 2.6 events/100 patient years, p<0.001).
There were also more frequent ER visits among patients receiving rivaroxaban than among those receiving apixaban (12.8 vs. 10.1 events/100 patient years, respectively; p=0.003). Additionally, mortality was higher in patients receiving rivaroxaban (3.5 vs. 2.6 deaths/100 patient years; p=0.047).
Overall, patients demonstrated the highest risk for any bleeding with rivaroxaban (37.9 events/100 patient years). Thrombotic event rates were similar between apixaban, rivaroxaban, and warfarin. Apixaban was observed to be associated with lower rates of mortality than rivaroxaban and warfarin.
Although the study included a large real-world data set, Dr. Schaefer noted that the inherent limitations associated with the observational study included the potential for selection bias and unadjusted confounding, as well as the lack of data on treatment adherence.
“While these findings should be confirmed with randomized studies, they could have implications for anticoagulant selection,” Dr. Schaefer said.
Any conflicts of interest declared by the authors can be found in the original abstract.
Reference
Schaefer J, Errickson J, Kong X, et al. A comparison of bleeding events among patients on apixaban, rivaroxaban, and warfarin for atrial fibrillation and/or venous thromboembolism. Abstract 135. Presented at the 65th American Society of Hematology Annual Meeting and Exposition; December 9, 2023; San Diego, California.