In COVID-19 patients with Type 2 diabetes, the use of the drug metformin before testing positive is linked to a threefold decrease in mortality in COVID-19 patients. Diabetes is an important co-morbid condition for COVID-19.
A racially diverse study was conducted at the University of Alabama at Birmingham and is published in the journal Frontiers in Endocrinology.
Leader of the study, Anath Shalev, M.D., director of UAB's Comprehensive Diabetes Center said, "This beneficial effect remained, even after correcting for age, sex, race, obesity, and hypertension or chronic kidney disease and heart failure. Since similar results have now been obtained in different populations from around the world -- including China, France and a UnitedHealthcare analysis -- this suggests that the observed reduction in mortality risk associated with metformin use in subjects with Type 2 diabetes and COVID-19 might be generalizable."
The researchers stated that this mechanism may be due to metformin's previously described anti-inflammatory and anti-thrombotic effects.
For the study, 25,326 patients tested for COVID-19 at the UAB Hospital between Feb 25 and June 22 2020 were included. Out of these patients, 604 patients were found to be COVID-19-positive and 311 were African Americans.
The primary outcome of the study was mortality in COVID-19-positive subjects and the potential link between subject characteristics or co morbidities was analyzed.
It was found that blacks, who comprised of 26 percent of Alabama's population, were 52 percent of those who tested positive for COVID-19 and only 30 percent of those who tested negative. In comparison, only 36 percent of the COVID-19-positive subjects were white, while whites made up 56 percent of those who tested negative. This further underlined the racial disparity.
However, once these patients tested positive, no significant racial difference in mortality was observed.
Shalev said, "In our cohort, being African American appeared to be primarily a risk factor for contracting COVID-19, rather than for mortality. This suggests that any racial disparity observed is likely due to exposure risk and external socioeconomic factors, including access to proper health care."
In the study, the overall mortality of COVID-19 positive patients was 11 percent. 93 percent of deaths were seen in patients over the age of 50, and being male or having high blood pressure was associated with a significantly elevated risk of death. Diabetes was associated with a higher mortality rate. 67 percent of deaths occurred in subjects with diabetes.
The researchers focused their attention on the effects of diabetes treatment on adverse COVID-19 outcomes, focusing mainly on insulin and metformin as the two most common medications for Type 2 diabetes. It was found that prior insulin showed no effect on the mortality risk. However, prior metformin use significantly reduced the risk of mortality in COVID-19 by 11 percent as compared to the 23 percent mortality for diabetes patients not on metformin.
Shalev said, "These results suggest that, while diabetes is an independent risk factor for COVID-19-related mortality. This risk is dramatically reduced in subjects taking metformin -- raising the possibility that metformin may provide a protective approach in this high-risk population."
Further studies are required to explore how metformin shows its protective effect, as well as assess the risks and benefits of metformin treatment and the indications for its use in the face of the ongoing COVID-19 pandemic.