Covid-19 is marked by heightened inflammation and abnormal clotting in the blood vessels, particularly in the lungs, and is believed to contribute to progression to severe disease and death.
The study, led by investigators at St Michael's Hospital in Canada, and the University of Vermont in the US, showed that heparin -- a blood thinner given regularly at low dose to hospitalised patients -- stops clots from forming and reduces inflammation. The details are available as a preprint on MedRxiv.
"This study was designed to detect a difference in the primary outcome that included ICU transfer, mechanical ventilation or death," said Mary Cushman, Professor of medicine from Vermont's Larner College of Medicine.
"While we found that therapeutic heparin didn't statistically significantly lower incidence of the primary composite of death, mechanical ventilation or ICU admission compared with low dose heparin, the odds of all-cause death were significantly reduced by 78 per cent with therapeutic heparin," said first author Michelle Sholzberg, Head of Division of Hematology-Oncology, at St. Michael's Hospital of Unity Health Toronto, and assistant professor at the University of Toronto.
The team conducted a randomised international trial that examined the benefits of administering a therapeutic full dose of heparin versus a prophylactic low dose to moderately ill patients admitted to hospital wards with Covid-19.
Four patients (1.8 per cent) with therapeutic heparin died versus 18 (7.6 per cent) with prophylactic heparin).
An additional meta-analysis presented in the preprint showed that therapeutic heparin is beneficial in moderately ill hospitalised patients but not in severely ill ICU patients.
"We believe that the findings of our trial and the multiplatform trial taken together should result in a change in clinical practice for moderately ill ward patients with Covid-19," Sholzberg said