Metformin boosts survival for female COVID-19 patients with obesity, type 2 diabetes

Metformin is associated with improved mortality rates among female COVID-19 patients with obesity or type 2 diabetes, according to a new study published in The Lancet Healthy Longevity. These trends were not observed among male COVID-19 patients.

Highlighting metformin’s “cytokine-reducing and sex-specific immunomodulatory effects,” the authors explored data from more than 6,000 hospitalized COVID-19 patients. Nearly 53% of those patients were women.

Overall, when looking at all patients included in the study, metformin was not associated with a significant decrease in mortality. Among obese women and those with type 2 diabetes, however, there was a clear link between the medication and an improved chance of survival.

The team, however, observed no association between metformin and improved mortality among men.

“Given the previously demonstrated effects of metformin on inflammation in women more than men, it is possible that the main mechanism of benefit from metformin is from reduced inflammation,” wrote lead author Carolyn T Bramante, MD, University of Minnesota in Minneapolis, and colleagues. “Our study of home metformin use also highlights the effect that medications can have early on in the disease course (because metformin is stopped at hospitalization in the U.S.A.). Our analysis supports the preventive use of metformin, before infection with SARS-CoV-2, to prevent severe COVID-19 in patients with diabetes or obesity.” 

Bramante et al. did emphasize, however, that this does not mean metformin treatment should begin when patients receive a COVID-19 diagnosis. Inpatient use is also not recommended.

Going forward, the team added, researchers should assess the potential value of metformin in patients from “all BMI categories.”

The study is available here.