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  • Writer's pictureLindsay Wall, PharmD, RPh

What Is the Optimal Thromboprophylaxis Dose, and How Does It Relate to COVID-19?

The SARS-CoV-2 virus, more publicly known as COVID-19, has been the cause of over 34 million cases and almost 617,000 deaths in the United States alone.

For people with pre-existing conditions, such as asthma, diabetes, and obesity, the risk of death from contracting the virus is even greater. As cases began to rise, studies were conducted and provided helpful information on how the COVID-19 virus affected certain people with specific pre-existing conditions.

Optimal Thromboprophylaxis is a preventative measure (like medicine) to reduce the likelihood of blood clots. Because there seems to be a relation between the COVID-19 and Thromboprophylaxis, you can read below to find out about the connections.

COVID-19 and Venous Thromboembolism

Patients who contracted SARS-CoV-2 were predisposed to venous thromboembolism (VTE), creating complications for the hospitalized patients and a higher mortality rate. The risks were more life-threatening in critically ill patients monitored in the intensive care unit.

Venous thromboembolism is a disorder that can cause pulmonary embolism and deep vein thrombosis. When someone suffers from a pulmonary embolism, a clot breaks lose, travels through the bloodstream, and gets into your lungs. Deep vein thrombosis also forms blood clots, but in your veins. These clots can form in your leg, thigh, or pelvis.

“Acutely ill hospitalized patients, particularly those who are admitted to an intensive care unit (ICU) because they are critically ill, are at an increased risk for venous thromboembolism (VTE) because of endothelial injury, hypercoagulability, and immobilization resulting in venous stasis . . . the use of pharmacologic or mechanical thromboprophylaxis is recommended for acutely ill and critically ill hospitalized patients to reduce the risk for VTE.”

Because those who had COVID-19 were exposed to venous thromboembolism, the combination of VTE and other pharmacological medications can have some severe side effects.

The Study: Thromboprophylaxis Dose

Three studies are evaluated in this article, “Events, Extracorporeal Membrane Oxygenation Treatment, or Mortality Among Patients With COVID-19 Admitted to the Intensive Care Unit” published in The INSPIRATION; “Thromboprophylaxis in COVID-19: Anti-FXa—the Missing Factor?” and “Dosing of thromboprophylaxis and mortality in critically ill COVID-19 patients.”

These studies were all conducted in 2020, and two found that high doses of thromboprophylaxis were associated with a lower mortality rate and another cumulative incidence of thromboembolic events. While the other found that rare bleeding events did occur, though they were not frequent. Other severe thrombocytopenia was assigned to intermediate-dose prophylactic anti-coagulator.

“Among critically ill COVID-19 patients with respiratory failure, high-dose thromboprophylaxis was associated with a lower risk of death and a lower cumulative incidence of thromboembolic events compared with lower doses.”

The study “Dosing of thromboprophylaxis and mortality in critically ill COVID-19 patients” finds that those patients who were the illest and put into ICU units were put onto the high-dose thromboprophylaxis. These patients had a lower risk of venous thromboembolism and a lower risk of death. Researchers conceded a consensus on the reports to the current disruptive idea that the dosing of thromboprophylaxis would be a standard dose but was now a higher dose.

While the studies were randomized, 1692 patients were scanned to see if they were eligible.

Only 600 went through the randomization, where four people died before getting the first thromboprophylaxis dose. As a result, only 562 patients took part in the study.

“In this multicenter randomized clinical trial of patients with COVID-19 admitted to the ICU, intermediate-dose compared with standard-dose prophylactic anticoagulation did not improve the primary composite efficacy outcome or its major components, including all-cause mortality and VTE.
Results were consistent in sensitivity analyses and key prespecified subgroups.”

Patients admitted to the ICT were given standard doses of the anti-coagulate prophylactic and did not see an improvement with VTE and risk of death. However, the results were similar across the board, along with the subgroups of the analysis.


Optimal Thromboprophylaxis is a preventative measure (like medicine) to reduce the likelihood of blood clots. The relation between COVID-19 and thromboprophylaxis was found to be a positive note from studies shown in the year 2020. All studies found a lower risk of death, even in those patients who had a high risk of mortality from respiratory disorders, while others found a slight chance of bleeding from a study of 562 people. Severe thrombocytopenia was assigned to intermediate-dose prophylactic anti-coagulator and proved a positive result.


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