According to a study in the Journal of Internal Medicine, apixaban was associated with a lower bleeding risk than warfarin or rivaroxaban during initial treatment for patients who experienced a first-time venous thromboembolism.
Investigators examined data from 6558 patients on warfarin; 18,196 on rivaroxaban; and 19,498 on apixaban. They assessed bleeding rates during 2 distinct phases of treatment: the initial 6 months and the extended treatment period spanning from 6 months up to 5 years.
Major bleeding rates per 100 patient-years were 3.86 for warfarin (95% CI, 3.14-4.58), 2.93 for rivaroxaban (95% CI, 2.55-3.31), and 1.95 for apixaban (95% CI, 1.65-2.25). After adjusting for relevant factors, investigators found that apixaban had a significantly lower bleeding risk compared with both warfarin (adjusted hazard ratio [aHR], 0.55) and rivaroxaban (aHR, 0.62).
In the extended treatment phase, major bleeding rates per 100 patient-years were 1.55 for warfarin (95% CI, 1.19-1.91), 1.05 for rivaroxaban (95% CI, 0.85-1.26), and 0.96 for apixaban (95% CI, 0.78-1.15). The aHRs indicated that both apixaban and rivaroxaban were associated with a lower bleeding risk compared with warfarin, with HRs of 0.60 and 0.72, respectively. However, the bleeding risk between apixaban and rivaroxaban was found to be similar (HR, 0.85).
The study also identified common risk factors for bleeding complications during both the initial and extended treatment phases. Previous bleeding events and increasing age were found to be associated with a higher risk of bleeding.
Regarding the results of their study, the investigators noted “the generalizability to other groups is unknown. It is important to keep in mind that patients included in the analysis on extended treatment were free of major bleeding during initial treatment, which could contribute to the low bleeding incidence.”