Clin Infect Dis
Metformin may cut long COVID risk in overweight adults by over 60%
Study details: This retrospective cohort study used the U.K. Clinical Practice Research Datalink Aurum database (March 2020–July 2023) to evaluate whether starting metformin within 90 days of SARS-CoV-2 infection reduces the risk of post-COVID-19 condition (PCC) in adults with overweight or obesity (BMI ≥25 kg/m²). Individuals with prior metformin use or contraindications were excluded. PCC was defined by diagnostic code or new-onset WHO-listed symptoms 90 to 365 days post-infection.
Results: Among 624,308 eligible patients, 2,976 initiated metformin post-COVID-19. The 1-year risk difference for PCC was -12.58% (hazard ratio 0.36; 95% CI, 0.32–0.41) in the intention-to-treat analysis, indicating a substantial reduction in PCC incidence. Subgroup analyses showed consistent benefit. The study notes that findings may not generalize to those with normal BMI.
Clinical impact: Early metformin initiation after COVID-19 in patients with overweight or obesity was associated with a marked reduction in PCC risk. These real-world data support and extend prior randomized trial findings, suggesting metformin may have a role in PCC prevention for this population, though causality and broader applicability require further study.
Source:
Chaichana U, et al. (2025, September 1). Clin Infect Dis. Effect of Metformin on the Risk of Post-coronavirus Disease 2019 Condition Among Individuals With Overweight or Obese: A Population-based Retrospective Cohort Study. https://pubmed.ncbi.nlm.nih.gov/40887815/