The study conducted on 6,195 patients by the University of Minnesota, University of Basel, Switzerland, and Columbia University found that patients on prescribed blood thinners before having covid were admitted less often to hospitals, despite being older and having more chronic medical conditions than their peers.

The study, claimed to be the largest in the world on the role of blood thinners in covid, evaluated patients aged above 18 from 4 March to 27 August 2020 among 12 hospitals and 60 clinics in the US.

The scientists investigated the relationship between 90-day anticoagulation therapy among outpatients before covid diagnosis and the risk for hospitalization and mortality and inpatient anticoagulation therapy and mortality risk.

“Blood thinners—regardless of they being used before being infected with covid or started when admitted to hospital for treatment of covid—reduce deaths by almost half,” the study said, adding that hospitalized covid patients benefit from blood thinners regardless of the type or dose of the medication used.

According to scientific evidence, some people with covid develop abnormal blood clots, including in the smallest blood vessels. The clots may also form in multiple places in the body, including in the lungs. This unusual clotting may cause different complications, including organ damage, heart attack and stroke. Researchers said clotting may be triggered by high levels of inflammation caused by SARS-CoV-2 infection. A high level of inflammation can affect multiple organs and result in severe disease. People who already have damaged blood vessels from diabetes or high blood pressure may be at higher risk of developing blood clots, said the scientists.

“We know covid causes blood clots that can kill patients. 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,” said lead author Sameh Hozayen, an assistant professor of medicine at the the University of Minnesota Medical School.

“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.