By Jeff Hansen
Use of 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 racially diverse study at UAB. Diabetes is a significant comorbidity for COVID-19.
“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,” Shalev said.
How metformin improves prognosis in the context of COVID-19 is not known, Shalev said. 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.
The study – first made available in MedRxiv and now published in the peerreviewed journal Frontiers in Endocrinology – included 25,326 patients tested for COVID-19 at the tertiary care UAB Hospital between Feb. 25 and June 22 of last year. Of the 604 patients found to be COVID-19-positive, 311 were Blacks.
The primary outcome in the study was mortality in COVID-19-positive subjects, and the potential association with subject characteristics or comorbidities was analyzed.
Researchers found that Blacks, who are 26% of Alabama’s population, were 52% of those who tested positive for COVID-19, and only 30% of those who tested negative. In contrast, only 36% of the COVID19-positive subjects were white, while whites made up 56% of those who tested negative, further underlining the racial disparity. Once COVID-19-positive, though, no significant racial difference in mortality was observed.
“In our cohort,” Shalev said, “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.”
Overall mortality for COVID-19-positive patients was 11%. The study found that 93% of deaths occurred in subjects older than 50, and being male or having high blood pressure was associated with a significantly elevated risk of death. Diabetes was associated with a dramatic increase in mortality, with an odds ratio of 3.62. Overall, 67% of deaths in the study occurred in subjects with diabetes.
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.