Comparing two DOACs for recurrent VTE and bleeding in patients with VTE

Introduction and methods

Background

To date, no results have been published from randomized trials, such as the ongoing COBRRA trial, directly comparing the efficacy and safety of apixaban with rivaroxaban in patients with VTE. The COBRRA trial is expected to be completed in December 2023. Until the results of this and other trials become available, the results of observational studies can be used to inform clinicians about the efficacy and safety of apixaban and rivaroxaban. However, in previous observational studies, the study population was relatively small or only data were used until 2015 [1,2], which is one year after apixaban was approved by the U.S. Food and Drug Administration for the treatment of VTE.

Aim of the study

The aim of this study to compare the effectiveness and safety of apixaban and rivaroxaban in adult patients with VTE.

Methods

The researchers conducted a retrospective new-user cohort study based on data from the Optum Clinformatics Data Mart database of a privately insured population in the US. Patients aged 18 years or older who initiated apixaban (n=28,287) or rivaroxaban (n=21,613) within 30 days of being diagnosed with VTE were included. Outpatients with VTE and patients in whom VTE was not in secondary position (i.e. not the primary reason for hospitalization) were excluded from participation. Also, patients who had been prescribed an anticoagulant or had developed a PE or DVT in the previous 12 months. (before the index VTE) were excluded. The median follow-up was 102 days (IQR: 30-128) in the apixaban group and 105 days (IQR: 30-140) in the rivaroxaban group.

Outcomes

The primary effectiveness outcome was the incidence of recurrent VTE (DVT or PE). The primary safety outcome was a composite of intracranial and gastrointestinal bleeding.

Propensity score matching was used to reduce differences in baseline characteristics between users of apixaban and rivaroxaban.

Main results

Effectiveness

• The incidence of recurrent VTE was lower in the apixaban group than in the rivaroxaban group (8.9 vs. 11.4 per 100 person-years; HR: 0.77; 95%CI: 0.69-0.87).
• The absolute reduction in the probability of recurrent VTE with apixaban compared with rivaroxaban was 0.006 (95%CI:0.005-0.011) within 2 months and 0.011 (95%CI:0.011 to 0.013) within 6 months of treatment initiation.
• Results were consistent for both DVT (HR: 0.85; 95%CI: 0.74-0.97) and PE (HR: 0.59; 95%CI: 0.39-0.91).

Safety

• The incidence of intracranial and gastrointestinal bleeding was lower in the apixaban group than in the rivaroxaban group (7.2 vs. 11.0 per 100 person-years; HR: 0.60; 95%CI: 0.53-0.69).
• The absolute reduction in the probability of gastrointestinal and intracranial bleeding with apixaban compared with rivaroxaban was 0.011 (95%CI:0.010 to 0.011) within 2 months and 0.015 (95%CI:0.013 to 0.015) within 6 months of treatment initiation.
• Results were consistent for both intracranial bleeding (HR: 0.54; 95%CI: 0.14-1.20) and gastrointestinal bleeding (HR: 0.60; 95%CI: 0.53-0.69).

Conclusion

References

Find this article online at Ann Intern Med.