Reduction in Initial Length of Stay with Rivaroxaban Single-Drug Regimen versus LMWH-VKA Standard of Care: Findings from the EINSTEIN Trial Program
Authors: van Bellen Bonno , Prins Martin , Bamber Luke , Wang Maria , Lensing Anthonie WA 
Published: October 2019

Abstract
Abstract 3419

Background
The current standard of care for the treatment of symptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE) is parenteral low molecular weight heparin (LMWH) or fondaparinux, overlapping with and followed by a vitamin K antagonist (VKA). According to guidelines, parenteral treatment should be discontinued only when patients have reached a stable level of anticoagulation with a VKA; defined as 2 consecutive measurements of international normalized ratio (INR) >2.0 at least 24 hours apart.
Compared with the previous standard of care, continuous infusion of unfractionated heparin, LMWH has made outpatient treatment feasible and lowered the treatment burden for patients, while reducing healthcare system costs. However, based on local practice or initial severity of disease many patients, especially those with PE, are still hospitalized, with discharge delayed until parenteral treatment can be discontinued.
Rivaroxaban is an oral anticoagulant that produces stable levels of anticoagulation without the need for dose adjustments or routine coagulation monitoring for acute or long-term treatment. With its oral mode of administration and without the need for parenteral bridging therapy, rivaroxaban has the potential to allow discharge based on a patient's clinical condition without the additional requirement of achieving adequate oral anticoagulation levels, thereby further reducing healthcare costs and increasing convenience for patients.

Aims
We investigated the potential of rivaroxaban to reduce the length of initial hospitalization and the proportion of patients hospitalized, using data from the EINSTEIN DVT and EINSTEIN PE studies.

Methods
The EINSTEIN DVT and EINSTEIN PE studies were large, open-label, randomized, non-inferiority phase III trials comparing oral rivaroxaban (15 mg twice daily for 3 weeks, followed by 20 mg once daily) with dose-adjusted subcutaneous enoxaparin (1.0 mg/kg twice daily) overlapping with, and followed by, warfarin or acenocoumarol (INR 2.0–3.0). There were no instructions in the protocols of the studies with regard to hospital admission and/or discharge, which were left to the judgment of the attending physician.
Length of hospital stay was evaluated from investigator records of dates of admission and discharge. All analyses were carried out in the intention-to-treat population using the van Elteren test, a stratified non-parametric test of significance, stratified by intended treatment duration. Analyses were exploratory with no adjustments for multiplicity.

Results
In the EINSTEIN DVT trial, 1781 of 3449 (52%) patients were hospitalized for the qualifying event, with similar proportions in each treatment arm (Table). However, the median length of hospital stay was significantly shorter in the rivaroxaban arm compared with the enoxaparin/VKA arm (5.0 vs 8.0 days; p<0.0001). In the EINSTEIN PE trial, 4328 of 4832 (90%) patients were hospitalized, with similar proportions in each treatment arm. Again, the median length of hospital stay was significantly shorter in patients receiving rivaroxaban than in patients receiving enoxaparin/VKA (6.0 vs 7.0 days; p<0.0001).

Conclusion
These results indicate that a single-drug anticoagulation regimen using rivaroxaban significantly reduces the length of hospital stay for patients admitted for DVT and/or PE, relative to standard of care. This has the potential to reduce the treatment burden for patients and healthcare systems.

Disclosures:
van Bellen: Bayer Brazil: Membership on an entity's Board of Directors or advisory committees. Prins:Bayer Healthcare: Consultancy, Honoraria. Bamber:Bayer Healthcare: Employment. Wang:Bayer Healthcare: Employment. Lensing:Bayer Healthcare: Employment.