The American Society of Hematology (ASH) has included an additional recommendation in its clinical practice guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19 (see TABLE). The updated guidelines, published recently in Blood Advances, include a conditional recommendation against outpatient anticoagulation prophylaxis in patients with COVID-19 who have been discharged but do not have suspected or confirmed venous thromboembolism (VTE).
Recommendation 3. The ASH guideline panel suggests against using outpatient anticoagulant thromboprophylaxis in patients with COVID-19 who are being discharged from the hospital and who do not have suspected or confirmed VTE or another indication for anticoagulation (conditional recommendation based on low certainty in the evidence about effects).
An individualized assessment of the patient’s risk of thrombosis and bleeding and shared decision-making are important when deciding on whether to use post-discharge thromboprophylaxis. Prospectively validated risk assessment models to estimate thrombotic and bleeding risk in COVID-19 patients following hospital discharge are not available.
The panel acknowledged that post-discharge thromboprophylaxis may be reasonable in patients judged to be at high thrombotic risk and low bleeding risk.
In February 2021, ASH published the guidelines to help clinicians determine when to use thromboprophylaxis in discharged patients who had recovered from COVID-19. The guidelines were developed by a multidisciplinary panel that also included three patient representatives. The panel performed systematic evidence reviews of relevant literature published up to March 2021 and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to examine the evidence and develop the recommendations.
The guideline panel agreed on two recommendations in the original ASH guideline document, both of which were open for public comment. The conditional recommendations were in favor of prophylactic-intensity anticoagulation versus intermediate-intensity or therapeutic-intensity anticoagulation for patients with COVID-19 who do not have confirmed or suspected VTE. These recommendations were based on “very low certainty” evidence and were focused on patients with COVID-19–related critical illness (i.e., requiring intensive care unit admission) and those with acute disease (i.e., admission to a COVID-19 ward without need for advanced support).
In the update, the guideline panel suggested against the routine use of post-discharge thromboprophylaxis in patients with COVID-19 who are being released from the hospital and do not have either confirmed or suspected VTE or any other indication for anticoagulation.
“This means that most patients should not receive prophylactic anticoagulation following discharge,” said lead author Adam Cuker, MD, of the University of Pennsylvania. “However, the panel noted that thromboprophylaxis may be appropriate in patients judged to be at high thrombotic risk and low bleeding risk.”
Data to support this new recommendation were “very uncertain” for all considered outcomes, according to the guideline panel. Some studies included in the review showed that prophylactic-intensity anticoagulation following discharge may reduce mortality (odds ratio [OR] = 0.55; 95% CI 0.37-0.83), corresponding to five fewer deaths per 1,000 individuals. Additionally, the evidence suggested that post-discharge prophylactic-intensity anticoagulation may reduce the risk of pulmonary embolism (OR=0.76, 95% CI 0.46-1.25), VTE (OR=0.76; 95% CI 0.46-1.25), and readmission (OR=0.92, 95% CI 0.41-2.05).
In the guideline, the panel noted that clinicians may wish to consider performing an individualized assessment of a patient’s thrombosis and bleeding risk before deciding on post-discharge thromboprophylaxis, and they recommended engaging patients in a shared decision-making approach.
Despite the new recommendation, the guideline panel noted that post-discharge thromboprophylaxis may be a reasonable approach in patients deemed at high thrombotic risk and low bleeding risk. According to the guideline authors, however, there is a lack of prospectively validated risk assessment models to estimate bleeding and thrombotic risk in patients with COVID-19 after discharge.
Although the power of the currently available evidence may not yet be sufficient to guide clinical practice confidently, forthcoming results from the MICHELLE (Medically Ill Hospitalized Patients for COVID-19 Thrombosis Extended Prophylaxis With Rivaroxaban Therapy) trial should provide higher quality evidence to support the recommendation, Dr. Cuker noted. The randomized, controlled MICHELLE trial evaluated the effects of post-discharge thromboprophylaxis.
“The panel will consider an update to the recommendation when this trial or other high-quality evidence is published,” Dr. Cuker added.
Any conflicts of interest declared by the authors can be found in the original article.
Cuker A, Tseng EK, Nieuwlaat R, et al. American Society of Hematology living guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19: July 2021 update on post-discharge thromboprophylaxis [published online ahead of print, 2021 Nov 2]. Blood Adv. doi: 10.1182/bloodadvances.2021005945.