In people with venous thromboembolism who have completed 6 to 12 months of anticoagulant therapy, does rivaroxaban (20 mg daily or 10 mg daily) decrease risk of symptomatic recurrent venous thromboembolism compared with aspirin (100 mg daily)?
Who? The study included 3396 adults who completed 6 to 12 months of anticoagulant therapy for objectively confirmed, symptomatic proximal deep vein thrombosis or pulmonary embolism in whom there was uncertainty about whether treatment should be continued.
What? The study compared 2 doses of rivaroxaban (20 mg daily or 10 mg daily) with aspirin (100 mg daily).
Rivaroxaban, 20 mg by mouth daily
Rivaroxaban, 10 mg by mouth daily
Aspirin, 100 mg by mouth daily
The 2 doses of rivaroxaban did not differ for any of the outcomes.
3 fewer people out of 100 taking rivaroxaban (20 mg daily or 10 mg daily) had symptomatic recurrent venous thromboembolism compared with those taking aspirin (100 mg daily).
Fatal thromboembolism, bleeding, and death from any cause did not differ for people who received rivaroxaban (20 mg daily or 10 mg daily) compared with those who received aspirin (100 mg daily).
In people with symptomatic venous thromboembolism who completed 6 to 12 months of anticoagulation, rivaroxaban at a standard dose or low dose for up to 12 additional months decreased recurrent symptomatic venous thromboembolism compared with aspirin, without increased bleeding.
Rivaroxaban vs aspirin in patients with symptomatic venous thromboembolism treated with 6 to 12 months of anticoagulation
Rate of events with rivaroxaban, 20 mg daily
Rate of events with rivaroxaban, 10 mg daily
Rate of events with aspirin, 100 mg daily
Absolute effect of rivaroxaban, 20 mg or 10 mg daily, at 1 year
Recurrent symptomatic venous thromboembolism*
About 3 fewer people out of 100 had recurrent symptomatic venous thromboembolism at 1 year.
Deep vein thrombosis
About 2 fewer people out of 100 had deep vein thrombosis at 1 year.
About 1 less person out of 100 had a pulmonary embolism at 1 year.
Fatal venous thromboembolism
Clinically relevant non-major bleeding
*Deep vein thrombosis and/or pulmonary embolism.
†Although the rates for the 2 groups look different, the differences were not statistically significant—this means that the difference could simply be due to chance rather than due to the different treatments.
‡Includes fatal bleeding.
This Evidence Summary is based on the following article:
Weitz JI, Lensing AWA, Prins MH, et al; EINSTEIN CHOICE Investigators. Rivaroxaban or Aspirin for Extended Treatment of Venous Thromboembolism. N Engl J Med. 2017;376:1211-22. PubMed
For Family Physicians
Secondary prevention of venous thromboembolism (VTE)
How long should I treat my patient with anticoagulants after VTE?
The duration of anticoagulation is determined by balancing the risk of recurrent VTE after stopping anticoagulation against the risk of bleeding if anticoagulation is continued. Contrary to popular belief, duration of treatment is not based on resolution of persisting thrombus on ultrasound or CT, which may be present in a substantial proportion of patients after initial treatment. Patients with VTE provoked by a major transient risk factor (e.g., surgery or pregnancy) are generally treated for 3 months. Extended therapy is considered for patients who have a minor risk factor (e.g., travel) or no clear risk factors, and prefer to continue protection from recurrent VTE.
The goal of the EINSTEIN CHOICE study was to determine if low-dose rivaroxaban would be as effective as standard-dose rivaroxaban at preventing recurrent VTE but with a lower risk of bleeding. Both doses were compared with aspirin because aspirin has been shown to reduce the risk of recurrent VTE by about one third, with a low risk of bleeding.1, 2
Can I apply the results of the EINSTEIN CHOICE study to my patients?
If you and your patient are uncertain about whether to continue anticoagulation after a minimum of 6 months of initial treatment, the results of the EINSTEIN CHOICE study provide reassurance that either low-dose or standard-dose rivaroxaban is more effective and just as safe as aspirin for preventing recurrent VTE. However, these results should not be applied to patients who have an ongoing risk factor (e.g., active cancer, ongoing immobility). Furthermore, due to the high proportion of patients enrolled in EINSTEIN CHOICE who had provoked VTE (60%), which is generally considered to have a lower risk of recurrence, it is less clear whether all patients with unprovoked VTE would be just as safe on low-dose rivaroxaban as on the standard dose.
Doctor, I have finished 6 months of treatment with rivaroxaban. Can I stop it now and take an aspirin instead?
If you wish to continue protection from another blood clot, remaining on rivaroxaban will protect you better than aspirin and the risk of bleeding on a daily basis is similar. However, if you bleed due to a physical injury, the bleeding is likely to be more severe if you are taking rivaroxaban. Rivaroxaban is also more expensive than aspirin and may not be not covered for extended treatment by your private or government drug plan.
Dr. Deborah Siegal
Dr. Deborah Siegal graduated from Queen's University School of Medicine in 2009 and completed Internal Medicine and Hematology training at McMaster University. She holds a Master of Science degree in Pharmacology from the University of Toronto and is completing a Master of Science degree in Health Research Methodology at McMaster University. Dr. Siegal is currently a Clinical Scholar in the Division of Hematology and Thromboembolism at McMaster University. She received a Thrombosis Canada Research Fellowship Award in 2014 and a Canadian Institutes of Health Research Fellowship Award in 2015.
Dr. Siegal's primary research interest is iatrogenic bleeding complications. She has published 34 articles in peer-reviewed journals, including scientific articles in N Engl J Med, Circulation, Blood, and J Thromb Hemost on anticoagulant-associated bleeding and reversal.
Lori-Ann Linkins, MD, MSc (Clin Epi), FRCPC
Dr. Linkins is an Associate Professor of Medicine (thrombosis) at McMaster University in Hamilton, Canada. She holds a Masters Degree in Health Research Methodology and is a Deputy Editor with the Health Information Research Unit, McMaster. Her research interests include heparin-induced thrombocytopenia and cancer-associated thrombosis. She was editor of the ACCP Guidelines, 9th Edition HIT chapter and is currently a member of the ASH VTE Guidelines HIT Panel.
Published: Thursday, August 17, 2017