Metformin lowers risk of long COVID

Treatment with the diabetes drug metformin immediately after testing positive for the SARS-CoV-2 virus lowers the risk of developing long COVID by 41%.

Researchers reported this finding on June 8, 2023 in The Lancet Infectious Diseases.

“Long COVID is a significant public health emergency that may have lasting physical health, mental health, and economic impacts, especially in socioeconomically marginalised groups. There is an urgent need to find potential treatments and ways to prevent this disease.” said first author Carolyn Bramante, M.D., Assistant Professor of Internal Medicine & Pediatrics at the University of Minnesota Medical School in Minneapolis. “Our study showed that metformin, a medication that is safe, low-cost, and widely available, substantially reduces the risk of being diagnosed with long COVID if taken when first infected with the coronavirus. This trial does not indicate whether metformin would be effective as a treatment for those who already have long COVID,” she added.

Subjects were not hospitalized, had a higher risk of developing severe COVID due to being overweight or obese, were over 30 years-old, had tested positive for SARS-CoV-2 within the last three days and were without a known prior SARS-CoV-2 infection.

Of 1323 subjects who received a dose of metformin or placebo, 1126 (564 metformin and 562 placebo) consented to long-term follow-up and completed at least one survey after an assessment for long COVID at day 180.

The investigators reported that 6.3% (35/564) of subjects treated with metformin received a long COVID diagnosis within 10 months of follow up, compared to 10.4% (58/562) of those receiving placebo, a 41% comparative reduction.

Writing in a Linked Comment, Jeremy Faust, M.D. of Harvard Medical School in Boston, said: “If confirmed, the findings from the study by Bramante and colleagues are profound …. This is the first high-quality evidence from a randomised controlled trial to show that the incidence of long COVID can be reduced by a medical intervention, metformin—an inexpensive treatment with which clinicians have ample experience.”