News Release

Prescribed blood thinners can help reduce hospitalizations related to COVID-19

U of M Medical School-led study finds that having a protocol to use blood thinners for COVID-19 patients reduces patient COVID-19 mortality by almost half

Peer-Reviewed Publication

University of Minnesota Medical School

The NIH has reported that many individuals with COVID-19 develop abnormal blood clots from high inflammation, which can lead to serious health complications and mortality. To find ways to decrease clotting related to COVID-19, researchers from the University of Minnesota and Basel University in Switzerland looked at reducing hospitalizations by using prescribed blood thinners.

“We know that COVID-19 causes blood clots that can kill patients,” said lead author Sameh Hozayen, MD, MSC, an assistant professor of medicine at the U of M Medical School. “But, do blood thinners save lives in COVID-19? Blood thinners are medications prescribed to prevent blood clots in patients with a prior blood clot in their lungs or legs. They also prevent blood clots in the brain secondary to abnormal heart rhythms, like atrial fibrillation. Blood thinners are the standard of treatment in these diseases, which is why we looked at data to see if it impacted hospitalizations related to COVID-19.” 

“We already know that overwhelmed hospitals have a higher risk for death among their patients, so reducing hospitalization may have a positive impact during a COVID-19 surge,” Hozayen said. 

Published in Lancet’s Open Access EClinical Medicine, the study found that:

  • patients on blood thinners before having COVID-19 were admitted less often to the hospital, despite being older and having more chronic medical conditions than their peers;

  • blood thinners — regardless of if they are being used before being infected with COVID-19 or started when admitted to the hospital for treatment of COVID-19 — reduce deaths by almost half; and,

  • hospitalized COVID-19 patients benefit from blood thinners regardless of the type or dose of the medication used.

“Unfortunately, about half of patients who are being prescribed blood thinners for blood clots in their legs, lungs, abnormal heart rhythms or other reasons, do not take them. By increasing adherence for people already prescribed blood thinners, we can potentially reduce the bad effects of COVID-19,” Hozayen said. “At M Health Fairview and most centers around the world now, there are protocols for starting blood thinners when patients are first admitted to the hospital for COVID-19 — as it is a proven vital treatment option. Outside of COVID-19, the use of blood thinners is proven to be lifesaving for those with blood coagulations conditions.”

Using de-identified data from M Health Fairview and after obtaining appropriate ethical committee approval, the study was a collaborative effort between U of M Medical School faculty Chris Tignanelli, Michael Usher, Zachary Kaltenborn, Surbhi Shah, and Diana Zychowski; U of M School of Public Health faculty Ryan Demmer, Pamela Lutsey, and Sydney Benson; and Basel University Pathology Institute faculty Alexander Tzankov and Jasmin Haslbauer. 

​​Researchers note that the next steps for this work is to ensure that the results of this study are consistent and not isolated to the health care systems in advanced countries — like the United States and Switzerland — or in certain populations, like Caucasians. They are currently working with research groups in other parts of the world, like Egypt, to look at how blood thinners impact patients in less-invested health care systems and in different patient populations. 


Dr. Hozayen and the research team are currently seeking funding from within and outside the University for a large collaborative nationwide study using data from a large de-identified multiple million patient NIH initiative. They aim to study how physicians can improve the outcomes of COVID-19 patients using FDA-approved therapies, like blood thinners, and other treatments. 

About the University of Minnesota Medical School
The University of Minnesota Medical School is at the forefront of learning and discovery, transforming medical care and educating the next generation of physicians. Our graduates and faculty produce high-impact biomedical research and advance the practice of medicine. We acknowledge that the U of M Medical School, both the Twin Cities campus and Duluth campus, is located on traditional, ancestral and contemporary lands of the Dakota and the Ojibwe, and scores of other Indigenous people, and we affirm our commitment to tribal communities and their sovereignty as we seek to improve and strengthen our relations with tribal nations. For more information about the U of M Medical School, please visit

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