Introduction: Acute venous thromboembolism (VTE) is a common, preventable complication in hospitalized medical patients that contributes to significant morbidity, mortality, and cost. Rivaroxaban, an oral factor Xa inhibitor, can be utilized as VTE prophylaxis at a dose of 10 mg daily. It is also approved for several other indications, including PAD, CAD, and post-ACS at a lower dose of 2.5 mg twice daily. Due to the difference in total daily dose for VTE prophylaxis versus these other indications, the VTE prophylactic benefits in hospitalized patients administered rivaroxaban 2.5 mg twice daily alone are unclear.
Methods: A retrospective, single-center cohort study was conducted at Vanderbilt University Medical Center (VUMC) to evaluate the safety and efficacy of administering non-rivaroxaban VTE prophylaxis in conjunction with rivaroxaban 2.5 mg twice daily in hospitalized patients with PAD, CAD and post-ACS. Patients were eligible for inclusion if they were 18 years or older, admitted to VUMC for at least 24 hours between January 1, 2022 and July 1, 2024, administered at least one dose of rivaroxaban 2.5 mg, and had an indication for VTE prophylaxis based on a VTE risk assessment score. The primary outcome was a composite of new VTE events and clinically significant bleeding. The individual components of the primary outcome, as well as hospital length of stay, were evaluated as secondary outcomes.
Results: Among the 138 encounters included in this study, nine patients were administered non-rivaroxaban VTE prophylaxis in conjunction with rivaroxaban 2.5 mg, while 129 patients received rivaroxaban 2.5 mg only. A total of four patients met the primary composite outcome. Although there was not a statistically significant difference in the primary outcome found between groups, there was a trend toward fewer events occurring with additional VTE prophylaxis, as all events occurred among patients who received rivaroxaban 2.5 mg only.
Conclusions: In this single-center, retrospective study in hospitalized patients, a statistically significant reduction in the primary composite outcome was not found with the addition of non-rivaroxaban VTE prophylaxis to rivaroxaban 2.5 mg. However, a trend toward favorable outcomes with additional VTE prophylaxis was seen, emphasizing the need for larger, prospective studies.
