Diabetes Drug Found Protective Against COVID-19

Metformin use found effective in preventing severe COVID-19 
covid depiction of sars
Alabama (Precision Vaccinations)

Treating people with the diabetes drug metformin before a diagnosis of COVID-19 is associated with a threefold decrease in mortality in COVID-19 patients with Type 2 diabetes, according to a study at the University of Alabama at Birmingham (UAB).

After controlling for other covariates, age, and gender, metformin use emerged as independent factors affecting COVID-19-related mortality. After controlling for all variables, death was significantly less likely — with an odds ratio of 0.33 — for Type 2 diabetes subjects taking metformin, compared with those who did not take metformin, said these UAB researchers.

“This beneficial effect remained, even after correcting for age, sex, race, obesity, and hypertension or chronic kidney disease and heart failure,” said Anath Shalev, M.D., director of UAB’s Comprehensive Diabetes Center and leader of the study, published on January 13, 2021.

“Since similar results have now been obtained in different populations worldwide, including China and France. These findings suggest that the observed reduction in mortality risk associated with metformin use in subjects with Type 2 diabetes and COVID-19 might be generalizable,” Dr. Shalev added.

How metformin improves prognosis in the context of COVID-19 is not known, Shalev says. 

The UAB findings suggest that the mechanisms may go beyond any expected improvement in glycemic control or obesity since neither body mass index, blood glucose, nor hemoglobin A1C were lower in the metformin users who survived as compared to those who died.  

“The mechanisms may involve metformin’s previously described anti-inflammatory and anti-thrombotic effects,” Shalev said.

Published in the peer-reviewed journal Frontiers in Endocrinology, this study included 25,326 patients tested for COVID-19 at the tertiary care UAB Hospital between Feb. 25 and June 22, 2020.

The study’s primary outcome was mortality in COVID-19-positive subjects, and the potential association with subject characteristics or comorbidities was analyzed.

The overall mortality for COVID-19-positive patients was 11 percent. 

The study found that 93 percent of deaths were in subjects over the age of 50.  Being male or having high blood pressure were associated with a significantly elevated risk of death. 

Diabetes was associated with a dramatic increase in mortality, with an odds ratio of 3.62.

The researchers looked at the effects of diabetes treatment on adverse COVID-19 outcomes, focusing on insulin and metformin as the two most common medications for Type 2 diabetes. They found that prior insulin use did not affect mortality risk.

However, prior metformin use was a different matter. 

Metformin use significantly reduced the odds of dying, and the 11 percent mortality for metformin users was not only comparable to that of the general COVID-19-positive population, but it was also dramatically lower than the 23 percent mortality for diabetes patients not on metformin.

“These results suggest that, while diabetes is an independent risk factor for COVID-19-related mortality,” Shalev said, “this risk is dramatically reduced in subjects taking metformin, raising the possibility that metformin may provide a protective approach in this high-risk population.” 

The researchers say future studies will need to explore how metformin is protective and assess the risks and benefits of metformin treatment and the indications for its use in the face of the ongoing COVID-19 pandemic.

Metformin used alone or with other medications, including insulin, treats type 2 diabetes, says Medline. Metformin helps control the amount of glucose (sugar) in your blood. It decreases the amount of glucose released from the liver and has other metabolic effects.

Metformin also increases your body's response to insulin, a natural substance that controls the blood’s amount of glucose. Metformin is not used to treat type 1 diabetes, a condition in which the body does not produce insulin and cannot control the amount of sugar in the blood.

This study is part of a new Precision Diabetes Program, a collaboration between the UAB Comprehensive Diabetes Center and the Hugh Kaul Precision Medicine Institute at UAB. Support came from the National Institutes of Health.

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