Blood thinners can reduce COVID-19 deaths by nearly half, study finds

The use of blood thinners by COVID-19 patients, either before being infected with the disease or afterward, can reduce deaths by almost half, according to new research.

The study, published in the open-access, peer-reviewed journal EClinicalMedicine, looked at ways to reduce clotting and hospitalizations related to COVID-19 through the use of prescribed blood thinners.

"We know that COVID-19 causes blood clots that can kill patients," Dr. Sameh Hozayen, lead author of the study and an assistant professor of medicine at the University of Minnesota Medical School, said in a news release. "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."

The study also found that patients on blood thinners before contracting the virus were admitted less often to hospital despite being older on average and suffering from more chronic medical conditions than their peers.

The study evaluated 6,195 adult COVID-19 patients, including 598 who were immediately hospitalized and 5,597 who were treated as outpatients, between March 4 and Aug. 28, 2020. Among the outpatients, 160 were already on blood thinners, and 331 were eventually hospitalized. Outpatients who were on blood thinners at the time of diagnosis had a 43 per cent reduced risk of hospitalization.

Hospitalized patients also benefitted from blood thinners regardless of the type or dose of medication used.

Most medical centres around the world currently have protocols for starting COVID-19 patients on blood thinners upon hospital admission, according to Dr. Hozayen. It’s easy to keep track of prescription drug use while in hospital, but among those who have previously been prescribed blood thinners and may want to benefit from this study, one of the challenges is getting them to adhere to their drug regimen.

"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," he said. "Outside of COVID-19, the use of blood thinners is proven to be lifesaving for those with blood coagulations conditions."