Can blood-sugar drug metformin cut Covid-19 death risk?

It also reduces inflammation proteins like TNF-alpha that appear to make Covid-19 worse, said the research published in the journal The Lancet Healthy Longevity.

"Seeing a bigger association with protection in women over men may point towards inflammation reduction as a key way that metformin reduces risk from Covid-19," said principal investigator Carolyn Bramante, Assistant Professor at the University of Minnesota Medical School in the US.

"However, more research is needed," Bramante said.

The study is based on analysis of de-identified patient data from healthcare company UnitedHealth Group.

The team analysed about 6,000 individuals with Type-2 diabetes or obesity who were hospitalised with Covid-19 and assessed whether or not metformin use was associated with decreased mortality.

They found an association that women with diabetes or obesity, who were hospitalised for Covid-19 disease and who had filled a 90-day metformin prescription before hospitalisation, had a 21 per cent to 24 per cent reduced likelihood of mortality compared to similar women not taking the medication.

There was no significant reduction in mortality among men.