Background:
Venous thromboembolism (VTE) is common among patients with severe
coronavirus disease 2019 (COVID-19). Anticoagulation in hospitalized COVID-19 patients has
been associated with survival benefit; however, the optimal thromboprophylaxis strategy has not
yet been defined.
Objective:
To identify published guidance reports by national and international societies regarding
thromboprophylaxis strategies in COVID-19 patients in different settings (outpatients, hospitalized,
post-discharge).
Methods:
A systematic review of the literature (Pubmed/EMBASE) was conducted independently
by two investigators.
Results:
Among 1942 initially identified articles, 33 guidance documents were included: 20 published
by national and 13 by international societies. These documents provide recommendations
mainly for hospitalized (97% of reports) and post-discharge (75%) COVID-19 patients, and less so
for outpatients (34%). Thrombotic and bleeding risk stratification prior to any treatment decision is
the cornerstone of all suggested thromboprophylaxis strategies; 81% of the documents recommend
thromboprophylaxis for all hospitalized patients with a prophylactic dosage of low molecular
weight heparin irrespective of VTE risk. Intermediate or therapeutic dose intensity is recommended
in high VTE risk patients by 56% and 28% of documents, respectively. Mechanical thromboprophylaxis
is suggested in case of high bleeding risk or contraindication to pharmacological thromboprophylaxis
(59% of documents). Extended pharmacological thromboprophylaxis is recommended
for patients with high VTE risk after hospital discharge (63% of documents). For non-hospitalized
outpatients, 28% of documents recommend pharmacological thromboprophylaxis for high VTE
risk.
Conclusion:
The current guidance identifies thromboprophylaxis in COVID-19 patients, especially
during hospitalization, as of major importance for the prevention of VTE. Recommendations are derived
from limited evidence from observational studies.