LONDON (BLOOMBERG) - Blood-thinning drugs reduced the risk of death from Covid-19 in a new study, pointing to one more promising tool as physicians scour their medicine cabinets for treatments to blunt the pandemic.

About 14 per cent of patients who were given anticoagulants within 24 hours of hospital admission died from the coronavirus, compared with 19 per cent of those who didn't, according to a study published Friday (Feb 12) in the British Medical Journal.

The patients were treated with heparin, an injected blood-thinner sold by generic-drug makers including Teva Pharmaceutical Industries Ltd.

Scientists have looked for existing, low-cost medications to help severely ill Covid-19 patients as more elaborate treatments disappoint.

One of the biggest successes so far has been dexamethasone, a steroid that has been shown to reduce the risk of death by one-third for patients on ventilators.

The findings on blood thinners are based on data from more than 4,000 patients, mostly men, from the US Department of Veterans Affairs.

They were hospitalised between March 1 and July 31 with Covid-19. The patients getting anticoagulants didn't have an increased risk of bleeding, according to the study.

The study is based on observation, which means the results need to be confirmed by clinical trials and some are underway, the scientists said.

The drugs may show a result because blood clots developing in major veins and arteries could be to blame for Covid deaths, according to the research.