The American Society of Hematology (ASH) published in February 2021 “Anticoagulation Guidelines in Patients with COVID-19”. (https://ashpublications.org/bloodadvances/article/5/3/872/475154/American-Society-of-Hematology-2021-guidelines-on). Despite the extensive work and using evidence-based methodology their findings were as follows:

The panel agreed on 2 recommendations. The panel issued conditional recommendations in favor of prophylactic-intensity anticoagulation over intermediate-intensity or therapeutic-intensity anticoagulation for patients with COVID-19–related critical illness or acute illness who do not have confirmed or suspected VTE.

These recommendations were based on very low certainty in the evidence, underscoring the need for high-quality, randomized controlled trials comparing different intensities of anticoagulation. They will be updated using a living recommendation approach as new evidence becomes available.

However, ongoing interim analysis of three randomized controlled trials, REMAP-CAP, ACTIV-4, and ATTACC (ClinicalTrials.gov: NCT 02735707, 04505774, and 04372589, respectively) will be used to update this recommendation.