Speculation of mechanisms includes anti-inflammatory effects
While the mechanisms behind metformin’s potential role in reducing mortality risk in COVID-19 are unknown, the authors note that the most obvious assumption – that improved glycemic control may be a key factor – is disputed by the study’s finding that blood glucose levels and hemoglobin A1c were not significantly different among COVID-19 survivors taking versus not taking metformin.
They point instead to metformin’s known anti-inflammatory and antithrombotic properties.
“We therefore hypothesize that, by exerting some of these effects, metformin might improve outcomes and we are now in the process of investigating this possibility further,” Dr. Shalev said.
Dr. Peters noted that anti-inflammatory properties, themselves, are not necessarily unique to metformin in the treatment of diabetes.
“Many other agents, such as sodium-glucose cotransporter 2 (SGLT2) inhibitors can reduce inflammation, so I don’t know if that would explain it, but it certainly could help,” she said. “[Reducing inflammation] is a hypothesis you see commonly with diabetes drugs, but I think there are also a lot of metabolic benefits from metformin.”
“It was fascinating that they had the A1c data and that survival with metformin didn’t appear to be as related to A1c levels as one might think,” she added.
Notably, a key advantage, should the effects and mechanisms be validated, is metformin’s high accessibility, Dr. Peters added.
“This doesn’t necessarily tell us what we can do to reduce the health care disparities surrounding COVID-19, but the fact that metformin is low cost and easily available is very important, so maybe it will help as we try to grapple with other risk factors.”
The authors have reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.