An intermediate level of anticoagulation (blood thinning) had an 86 per cent probability of being more helpful than low or high dose anticoagulation in Covid patients, according to a new study.

The study was based on randomised clinical trial to test different levels of anticoagulation in more than 1,500 patients in India, Australia, New Zealand and Nepal.

The AustralaSian Covid-19 Trial (ASCOT) has pinpointed the most efficient level of blood thinning treatment needed for patients hospitalised with Covid, in the study which has been published in the New England Journal of Medicine Evidence and presented at the American Society for Hematology conference.

According to officials, patients in hospital with Covid-19 are at increased risk of blood clots (or thromboses), which in turn may contribute to development of organ failure.

“Anticoagulant use was recommended in all Covid treatment guidelines including in India but the most effective and safest dose is not known. This trial was done to find out the dose that provided the most benefit at the lowest risk.

"Many treatment guidelines recommend the use of low doses but are less certain in their recommendations about higher doses for the treatment of hospitalised non–critically ill adults with Covid-19 and recommend that more studies be done to establish their safety and efficacy," said Vivekanand Jha, executive director of George Institute for Global Health India.

"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 anticoagulation had an 86 pc probability of being better than low-dose anticoagulation. A higher therapeutic dose did not show any benefit. This finding will likely lead to changes in treatment guidelines with regard to optimal dosing," he added.

Delta wave

Jha explained that even though the case numbers were low in Australia and New Zealand, existing network relationships allowed the team to take the trial to India and Nepal, where Covid-19 was active and successfully complete this study that asks a question of global relevance.

"The rapid subject recruitment during the difficult time of the delta wave is a testimony to the commitment of site investigators and study staff in these centres," he said.

To expand the clinical evidence for use of anticoagulation and antiplatelet agents in hospitalised non-critically ill patients with Covid of diverse ethnicity from both high- and low- and middle-income countries, the team designed an international adaptive randomised clinical trial to compare the effectiveness of low-dose, intermediate-dose, low-dose plus aspirin, and therapeutic-dose anticoagulation with regard to death or the requirement for new organ (cardiac or respiratory) support by day 28.

According to Zoe McQuilten, Associate Professor, Monash University, the researchers did not find any evidence that the intermediate dose of anticoagulation resulted in increased risk of bleeding.

"While we didn't find evidence of benefit from the high therapeutic dose of anticoagulation, we enrolled fewer patients into that arm of the trial".