Aspirin Didn’t Improve Survival for Hospitalized COVID-19 Patients, Study Finds

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Key Takeaways

  • Antiplatelet agents such as aspirin failed to benefit critically ill adults with COVID-19, a recent study found. 
  • Experts say people with COVID-19 are at an increased risk of blood clots due to inflammation.
  • Staying active and minimizing the risk of contracting COVID-19 can help decrease the risk of blood clots.

Blood-thinning medications such as aspirin failed to effectively benefit critically ill adults with COVID-19 admitted to an intensive care unit (ICU), according to a recent study.

Researchers studied 1,557 critically ill COVID-19 patients from an ongoing trial. Thirty-four percent were women and the average age was 57. Patients were randomly assigned to take either aspirin, a P2Y12 inhibitor, or no antiplatelet therapy for up to 14 days. 

The study concluded among the critically ill patients with COVID-19, those that received blood-thinning treatment compared with no antiplatelet agent, “had a low likelihood of providing improvement in the number of organ support-free days within 21 days.” 

What Is Antiplatelet Therapy?

Antiplatelet drugs stop the formation of clots within blood vessels and reduce the size of a clot during a stroke. Aspirin is a commonly used antiplatelet drug.

In other words, giving aspirin to critically ill patients with COVID-19 in the ICU did not help them improve, but rather increased the risk of major bleeding in patients.

“Aspirin is effective for preventing blood clots in particular circumstances, but it is ineffective in patients in the ICU because it does not target the mechanism of blood clot formation in critically ill patients,” Mark Crowther, MD, MSc, professor of medicine at McMaster University who was not involved in the study, told Verywell in an email. “There is no reason to add aspirin to heparin—medication used to prevent blood clots or decrease clots that have already formed—or low molecular heparin in the ICU or elsewhere in the hospital because there’s no evidence that it benefits, but it will increase the risk of bleeding.” 

The findings were published in the Journal of the American Medical Association (JAMA)

Can COVID Increase the Risk of Blood Clots? 

Blood clotting occurs when specific parts of your blood thicken, according to Crowther. He added that blood clotting is often triggered when an injury takes place in an artery or vein which causes bleeding to start, signaling the body to turn on the blood clotting system which builds a mesh across the injury and is then filled by blood cells causing the bleeding to stop. 

Fady Youssef, MD, a board-certified pulmonologist and critical care specialist at MemorialCare Long Beach Medical Center in California, told Verywell via email that platelets also play a major role in clotting. These are the cells that rush when an injury to a blood vessel occurs and plugs up the damaged areas, forming a blood clot. 

Youssef said some factors can increase the risk of blood clots, including:

  • Prolonged periods of immobility (long plane or car ride)
  • Obesity
  • Age
  • Active cancer
  • Recent surgery
  • Birth control methods containing estrogen
  • Family history

While the risk of developing blood clots in the general population is very small, Youssef said, patients with COVID-19 have an increased risk.

“We do know that patients with COVID have had an increase in their risk of developing blood clots,” he said. “A situation where a patient has an underlying process that is leading to a high inflammatory state, leads platelets to abnormally form blood clots, is likely one of the ways COVID patients form blood clots.” 

Inflammation initiates clotting and decreases the activity of inflammatory cytokines, which are proteins that help regulate the body’s responses to disease and infection. Some people who are infected with COVID-19 have massive inflammatory responses, which can raise clotting factors in the blood.

Aspirin Does Not Help

Adding aspirin as a treatment or preventative measure to reduce the risk of blood clots in critically ill adults with COVID-19 is ineffective and supports the fact it should not be used, Crowther said. 

“Aspirin doesn’t work in this setting. We don’t want people to start thinking that taking aspirin will prevent COVID complications because it will not,” he said. “If patients are admitted to the hospital, or to the ICU, they should follow the advice of their doctor with respect to drugs to prevent blood clots.” 

In addition, adding aspirin on top of regular heparin treatment does not seem to have benefits or slow down the progression of organ failure syndromes, Alex Spyropoulos, MD, professor of medicine at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, told Verywell.

Selected patients with vascular issues such as heart attacks may benefit from adding aspirin to other anticoagulants (medicine that helps prevent blood clots), Crowther said.

What Does Treatment Look Like For Blood Clots? 

Treatment for blood clots will depend on where the clot is located in the body and the severity of the condition. Patients are typically treated with blood thinners that would prevent any further clots from forming while the body is given time to heal and resolve the existing clot, Youssef explained. 

In very special instances, healthcare professionals may use clot busters which would dissolve the clot in a very short time. 

There are other forms of treatment including catheter-directed treatments which is a non-surgical method that dissolves clots in the legs, thighs, or pelvis. There is also surgical thrombectomy, which is when the clot is surgically removed from the vein or artery.

“The drugs that we use to prevent them have been available for decades, are highly effective, and are highly safe,” Crowther said. “Although [this] research on patients with COVID has provided us with additional information on how to use these drugs, that information only applies to patients with COVID and, at a very fundamental level, none of the research from patients with COVID has fundamentally changed our approach to preventing blood clots.” 

What This Means For You

Critically ill patients with COVID-19 may not benefit from taking blood-thinning medication like aspirin. Talk to a healthcare provider about the best treatments to address blood clots if you are severely ill with COVID-19.

Can You Prevent Blood Clots?

Patients who are in the ICU can do little or nothing to prevent their blood clots because they are generally unconscious and receiving many medications, Crowther said. Healthy lifestyle choices can reduce the likelihood that one will end up in the ICU, and possibly reduce the risk of blood clots. However, Crowther claimed this is a generic preventative strategy and isn’t specific to patients in the ICU. 

“If you’re on either an aspirin or a blood thinner for other reasons (history of blood clots, stroke, or heart disease), do not discontinue your aspirin if you have COVID,” Spyropoulos said. He advises following the medical advice given by a healthcare provider.

Youssef added that the best thing for people to do to minimize their risk of developing blood clots is to remain active and follow guidance to minimize the risk of re-contracting COVID-19.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. REMAP-CAP Writing Committee for the REMAP-CAP Investigators. Effect of antiplatelet therapy on survival and organ support–free days in critically ill patients with COVID-19: A randomized clinical trial. JAMA. Published online March 22, 2022. doi:10.1001/jama.2022.2910

  2. Esmon CT. The interactions between inflammation and coagulation. Br J Haematol. 2005;131(4):417-430. doi:10.1111/j.1365-2141.2005.05753.x

  3. Galiatsatos P, Brodsky R. What does COVID do to your blood? Johns Hopkins Medicine.

  4. Johns Hopkins Medicine. Blood clot treatment

  5. Muck PE. Catheter-directed thrombolytic therapy. Society for Vascular Surgery.

  6. Johns Hopkins Medicine. Surgical thrombectomy.

By Alyssa Hui
Alyssa Hui is a St. Louis-based health and science news writer. She was the 2020 recipient of the Midwest Broadcast Journalists Association Jack Shelley Award.