Minneapolis—The common diabetes medication metformin appears to help protect against developing so-called long COVID, according to a new study.

The report in Diabetes Care points out that adults who use the prescription drug metformin to treat their type 2 diabetes have a lower risk of developing long COVID or dying after a COVID-19 infection compared with diabetes patients who take other antidiabetic medications. The study, led by the Institute for Health Informatics at the University of Minnesota, was supported by the National Institutes of Health (NIH).

The study is part of the NIH-funded Researching COVID to Enhance Recovery (NIH RECOVER) Initiative.

Last year, an earlier NIH-supported clinical trial indicated that metformin treatment reduced the risk of long COVID by as much as 40% in nearly 1,300 U.S. adults who were overweight or obese; most of those participations did not have diabetes. The researchers sought to determine if metformin, the usual first-line treatment for diabetes, had a similar effect on those patients. To do that, the study team examined electronic health record data for nearly 38 million Americans from two large U.S. databases.

Health records from 75,996 adults taking metformin for type 2 diabetes (T2D) to 13,336 records from patients who were not taking metformin but were using other types of diabetes medicines. The focus was on how many patients either died or were diagnosed with long COVID within 6 months after infection. The results indicated that patients taking metformin had a 13% to 21% lower incidence of long COVID or death than those in the nonmetformin group.

The researchers posit that metformin might have several mechanisms that reduce inflammation, decrease viral levels, and suppress the formation of disease-related proteins.

Long COVID is marked by a wide range of symptoms, including chronic fatigue, brain fog, and chest pain, that vary from person to person and can last for weeks, months, or years after infection from SARS-CoV-2—the virus that causes COVID-19. While rates of new cases have decreased since early in the COVID-19 pandemic, millions of people are still living with it.

“Studies show metformin use before and during SARS-CoV-2 infection reduces severe COVID-19 and postacute sequelae of SARS-CoV-2 (PASC) in adults,” the authors noted. “Our objective was to describe the incidence of PASC and possible associations with prevalent metformin use in adults with type 2 diabetes mellitus (T2DM).”

The retrospective cohort analysis used the National COVID Cohort Collaborative (N3C) and Patient-Centered Clinical Research Network (PCORnet) electronic health record (EHR) databases with an active comparator design that examined metformin-exposed individuals versus nonmetformin-exposed individuals who were taking other diabetes medications. T2D was defined by HbA1C ≥6.5 or T2D EHR diagnosis codes. The outcome was death or PASC within 6 months, defined by EHR code or computable phenotype.

Specifically, the hazard ratio (HR) for death or PASC with a U09.9 diagnosis code (PASC-U09.0) was 0.79 (95% CI, 0.71-0.88; P <.001), and for death or N3C computable phenotype PASC (PASC-N3C) was 0.85 (95% CI, 0.78-0.92; P <.001). In PCORnet, the HR for death or PASC-U09.9 was 0.87 (95% CI, 0.66-1.14; P = .08) and for death or PCORnet computable phenotype PASC (PASC-PCORnet) was 1.04 (95% CI, 0.97-1.11; P = .58). Incident PASC by diagnosis code was 1.6% metformin versus 2.0% comparator in the N3C and 2.1% metformin versus 2.5% comparator in PCORnet. By computable phenotype, incidence was 4.8% metformin and 5.2% comparator in the N3C and 24.7% metformin versus 26.1% comparator in PCORnet.

“Prevalent metformin use is associated with a slightly lower incidence of death or PASC after SARS-CoV-2 infection,” the researchers explained. “PASC incidence by computable phenotype is higher than by EHR code, especially in PCORnet. These data are consistent with other observational analyses showing prevalent metformin is associated with favorable outcomes after SARS-CoV-2 infection in adults with T2DM.”

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.