An intermediate dose of blood thinners saves Covid patients, says new study

Anti-coagulant use was recommended in all COVID-19 guidelines, including those in India, but the most effective and safest dose was never quantified. The AustralaSian COVID-19 Trial (ASCOT) study has pinpointed the most efficient level of blood thinning treatment needed for patients hospitalised with COVID-19. The study has been published in the “New England Journal of Medicine” and the evidence was presented at the American Society for Haematology conference. The ASCOT team conducted a randomised clinical trial to test different levels of anti-coagulation (or blood thinning) in more than 1,500 patients in Australia, New Zealand, India and Nepal (between February 2021 and March 2022).

“More studies need to be done to establish the safety and efficacy of anti-coagulants in Covid situations,” says Dr Vivekanand Jha, Executive Director of the George Institute for Global Health. “It is for this reason that the consortium put together this study. We evolved our approach as new evidence became available. Our findings show that an intermediate level of anti-coagulation had an 86 per cent probability of working better than low-dose anti-coagulation. A higher therapeutic dose did not show any benefit. This finding will likely lead to changes in treatment guidelines with regard to optimal dosing. The fact that the intermediate dose was better means more patients treated with this regime were more likely to survive or require organ support at 28 days. Importantly, however, this approach will save more lives in future once it becomes part of the Indian guidelines and is incorporated into routine practice for the treatment of hospitalised but non–critically ill adults with COVID-19. This trial is especially relevant to India as 1,273 out of 1,526 participants were recruited in Indian hospitals,” Dr Jha adds.

ASCOT Principal Investigator Professor Steven Tong, an infectious diseases clinician at the Royal Melbourne Hospital and co-lead of clinical research at the Doherty Institute, says the findings will inform WHO-sponsored guidelines. “The current practice in Australia is for low dose of anti-coagulation, while international guidelines recommend a higher therapeutic dose of anti-coagulation. Therefore, our findings provide evidence that a middle ground may be most beneficial,” he adds.

Professor Bala Venkatesh, Professorial Fellow at The George Institute for Global Health, Australia, says, “This study highlights the importance of conducting clinical trials in different healthcare systems. Low and middle-income countries (LMIC) have been under-represented in COVID-19 studies and ASCOT is one of the few studies to have a major involvement of LMIC regions. The results of the ASCOT trial are expected to have a significant influence on clinical guidelines.”

The ASCOT trial for non-critically ill patients hospitalised with COVID-19 was sponsored by the University of Melbourne while the George Institute for Global Health (Sydney, New Zealand, Australia and New Delhi) oversaw operations. Many treatment guidelines (including the Indian ones) recommend the use of low doses but are less certain in their recommendations about higher doses for the treatment of non critically ill adults with COVID-19.