Metformin may reduce risk of long COVID and death by 53%, study suggests

A study published in the Journal of Medical Virology suggests that patients prescribed metformin, a medication used to treat type 2 diabetes and prediabetes, within six days of a COVID-19 infection may have a reduced risk of developing long COVID or dying.

Study Methodology and Findings

Researchers from the University of Minnesota Medical School conducted a target trial emulation using electronic health records. The study utilized data from the US National COVID Cohort Collaborative (N3C), which includes health records from more than 21 million people. The researchers identified adults who had tested positive for COVID-19 between March 2020 and September 2023.

To conduct the comparison, scientists analyzed 248 people who received a new metformin prescription within six days of a documented SARS-CoV-2 diagnosis. This group was compared against a control group of 248 people who were prescribed other medications—specifically fluvoxamine, fluticasone, ivermectin, or montelukast—within the same six-day timeframe. To ensure the groups were comparable, researchers excluded individuals who were already taking metformin or those with conditions such as diabetes, PCOS, or gestational diabetes that might explain the prescription.

According to the study authors, "Metformin prescription within the week following documented SARS-CoV-2 infection was associated with a 53% reduction in LC/D [long COVID or death] over 6 months in this primarily Omicron-infected sample."

In terms of specific incidence rates, the study reported the following over a six-month period:

• Metformin group: 4.0% incidence (10 out of 248 people) developed long COVID or died.
• Control group: 8.5% incidence (21 out of 248 people) developed long COVID or died.
• Overall weighted incidence: 6.3% across both groups.
• Absolute risk reduction: 4.5 percentage points for the metformin group.

Approximately half of the metformin cohort and 52% of the control group were infected with the Omicron variant of SARS-CoV-2.

Context and Future Research

Metformin is currently used as a first-line treatment for type 2 diabetes in adults and children aged 10 years and above. It is also used to manage Polyendocrine Metabolic Ovarian Syndrome (PMOS), formerly known as Polycystic Ovary Syndrome (PCOS). Researchers have been investigating the drug's potential antiviral and anti-inflammatory effects during the early stages of infection.

The authors noted that these findings align with a previous sequential target trial analysis conducted in the United Kingdom. That analysis assessed metformin started within 90 days of infection and reported a hazard ratio (HR) of 0.36. However, the authors stated, "The replication of results in clinical trials is important for informing treatment guidelines."

Understanding Long COVID

Long COVID refers to symptoms that occur after a SARS-CoV-2 infection that cannot be explained by another diagnosis. Reported symptoms include fatigue, brain fog, cognitive difficulties, breathlessness, sleep disturbances, and problems with everyday activities. These symptoms can persist for months or years. Research has also suggested that brain inflammation may remain even after the virus is no longer detectable.

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Sources

• cidrap.umn.edu: Metformin given within a week of COVID-19 slashes risk of long COVID, death by 53%, paper notes | CIDRAP
• healthandme.com: Common Diabetes Drug Metformin May Slash Long COVID Risk By More Than 50% | Health and Me

This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.