A study has found that metformin use in type 2 diabetes patients might reduce their risk of dying from COVID-19. Experts say the randomized trials necessary for proving this aren’t likely to occur, though.
The study results have not been peer-reviewed and were published in July. Andrew B. Crouse, PhD of the Hugh Kaul Precision Medicine Institute at the University of Alabama at Birmingham and his colleagues conducted the study.
Metformin use was associated with an almost 70% mortality reduction after adjusting for multiple confounders in the study, which involved over 600 patients with COVID-19 and diabetes.
“Because metformin exerts various effects beyond its glucose-lowering action, among which are anti-inflammatory effects, it may be speculated that this biguanide might positively influence the prognosis of patients with [type 2 diabetes] hospitalized for COVID-19,” said André J. Scheen, MD, PhD, of Liège University, Liège, Belgium. “However, given the potential confounders inherently found in observational studies, caution is required before drawing any firm conclusions in the absence of randomized controlled trials.”
“Metformin users tend to do better in many different settings with respect to many different outcomes. To me, it is still unclear whether metformin is truly a miracle drug or whether it is simply used more often among people who are healthier and who do not have contraindications to its use,” said Kasia Lipska, MD, of Yale School of Medicine in New Haven, Connecticut. “I don’t think we have enough data to suggest metformin use for COVID-19 mitigation at this point.”
The researchers reviews 604 patients’ data. The patients were confirmed to test positive for COVID-19 between February 25 and June 22. 40% of them had diabetes.
Death occurred in 67, or 11 percent. The death odds ratio for those with versus without diabetes was 3.62 (P < .0001).
Over 60% of all deaths were people with diabetes. Age 50-70, male sex and diabetes were independent predictors of death.
A “mini review” published on August 1 in Diabetes and Metabolism summarizes data from four prior studies also showing reduced COVID-19 mortality in metformin users. These studies, taken together, showed that metformin created a 25% reduction in death. The largest of these studies found a reduction in mortality in women but not men.
Numerous drugs containing metformin have been recalled because they were contaminated with NDMA, a probable carcinogen. Lawsuits regarding this contamination are currently being filed on behalf of consumers of metformin.