Researchers have found that people with diabetes undergoing treatment with the medication metformin are at significantly less risk of death due to COVID-19 compared with those not taking the medication.
The study, which appears in the journal Frontiers in Endocrinology, also found that Black study participants were disproportionately more likely to contract the virus than white participants.
COVID-19 risk factors
A critical area of COVID-19 research has focused on the risk factors that may make a person more likely to either get a SARS-CoV-2 infection or die from COVID-19 if they develop it.
SARS-CoV-2 is a novel coronavirus, and while it bears some similarities to other coronaviruses, there is still much that researchers are yet to uncover about how and why it affects some people more than others and how to mitigate the risks.
Studies have begun to emerge demonstrating associations between specific health issues, demographic characteristics, and the chances of contracting SARS-CoV-2 or dying from COVID-19. This research backs up early anecdotal evidence and observational studies.
The more studies that provide convincing evidence of these links, the more robust the overall findings. Meta-analyses of the available scientific literature can then demonstrate the overall picture.
In the present study, the researchers were interested in exploring the patient characteristics associated with COVID-19 in United States populations that included many Black people.
The researchers note that Black people tend to be at higher risk of key comorbidities that could make them more likely to develop COVID-19, including diabetes.
The researchers also highlight that COVID-19 disproportionately affects Black adults, as well as various marginalized groups â€” findings that reflect already existing widespread health inequities resulting from systemic racism.
More than 25,000 patients
The researchers looked at de-identified electronic health record data to provide them with demographic and medical information for each person.
A total of 604 people tested positive for COVID-19, which the researchers note is a relatively low rate. They speculate that this may be due to the number of asymptomatic hospital staff and patients receiving elective procedures who had tests.
Disproportionate number of Black patients
However, the rate of death due to COVID-19 in Black patients was not significantly different than that in white patients.
According to Prof. Anath Shalev, director of UABâ€™s Comprehensive Diabetes Center and leader of the study: â€œIn 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 healthcare.â€
Diabetes and metformin
Of the people who tested positive for COVID-19, 70% had hypertension, 61% had obesity, and 40% had diabetes.
Of the patients who tested positive for COVID-19, 11% died. In 93% of cases, the person who died was over the age of 50 years.
The researchers also found that being male and having hypertension were associated with an increased risk of death from COVID-19.
People with diabetes accounted for 67% of deaths, suggesting that this condition had a particularly significant effect on the risk of death.
The researchers then analyzed the data to account for potential covariates that may affect other risk factors. They identified age, sex, and diabetes as key independent risk factors for death due to COVID-19.
Finally, the researchers looked in more detail at the people with diabetes. They found that those who tested positive who were taking metformin â€” a medication that doctors use to treat diabetes â€” had an 11% risk of dying, which was the same as that of the general population. In comparison, those with diabetes not taking metformin had a 24% risk of dying.
Prof. Shalev notes, â€œThis beneficial effect remained, even after correcting for age, sex, race, obesity, and hypertension or chronic kidney disease and heart failure.â€
â€œSince similar results have now been obtained in different populations from around the world â€” including China, France, and a [UnitedHealth] analysis â€” 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.â€
â€“ Prof. Anath Shalev
However, among those with diabetes who took metformin, body mass index (BMI), blood glucose levels, and hemoglobin A1C levels were no higher in the people who died than in those who survived.
As a consequence, Prof. Shalev suggests that â€œ[t]he mechanisms may involve metforminâ€™s previously described anti-inflammatory and antithrombotic effects.â€
To further develop the findings, the researchers suggest that future research should look at why metformin may have this protective effect and the possible risks and benefits of prescribing the medication to protect against COVID-19.