Widely used diabetes drug may offer unexpected health benefit
Adults with type 2 diabetes taking metformin before catching COVID-19 had a 39% lower risk of dying in the year following their infection than patients taking another diabetes medication, according to new research.
The study, published in the journal Diabetes, Obesity and Metabolism, analyzed medical records of 53,332 U.S. adults with type 2 diabetes who tested positive for COVID-19 between October 2021 and November 2023. Researchers compared patients taking metformin with those taking dipeptidyl peptidase-4 inhibitors (DPP4i).
Study Details
Most of the group, 50,965 patients, were taking metformin, while 2,367 were taking a DPP4i. Patients on metformin were slightly younger on average, 60 years old compared with 64 for those on the alternative medication.
After adjusting for age, gender and other variables, the researchers found that patients taking metformin were more likely to survive over the following year. The data initially suggested a 13% drop in long COVID symptoms among metformin users, though further statistical testing found no statistically significant link.
Potential Mechanisms
Researchers noted that metformin may help regulate a biological pathway involved in blood pressure and fluid balance that influences the severity of COVID-19. Earlier studies have also indicated that metformin can reduce inflammation and lower viral levels in the body during an active infection.
Put simply, people on metformin are generally healthier than people on DPP-4 inhibitors.
Expert Commentary
An independent epidemiologist explained that patients on metformin are generally healthier and younger than those prescribed DPP-4 inhibitors, which are typically reserved for older patients or those with kidney disease. "Metformin is the first drug most people with type 2 diabetes are given," noted Ziyad Al-Aly, M.D., a senior clinical epidemiologist at Washington University in St. Louis.
The new analysis aligns with other recent research, including a study from the University of Minnesota Medical School that showed patients prescribed metformin within six days of a COVID-19 diagnosis were less likely to die or develop long COVID. Al-Aly emphasized that while there is some evidence metformin may lower the risk of long COVID when started early, this still needs confirmation in large, well-designed randomized trials.
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