Abstract: | Revised: 8 February 2021 | Accepted: 10 February 2021 DOI: 10.1002/jmv.26873 RESEARCH ARTICLE Outpatient metformin use is associated with reduced severity of COVID‐19 disease in adults with overweight or obesity Carolyn T. Bramante MD, MPH1 | John Buse MD, PhD2 | Leonardo Tamaritz MD3 | Ana Palacio MD, MPH3 | Ken Cohen MD4 | Deneen Vojta MD4 | David Liebovitz MD5 | Nia Mitchell MD, MPH6 | Jacinda Nicklas MD, MPH7 | Ildiko Lingvay MD, MPH, MSCS8,9 | Jeanne M. Clark MD, MPH10 | Louis J. Aronne MD11 | Erik Anderson MD, MPH12 1 | Michael Usher MD, PhD | Ryan Demmer PhD, MPH Genevieve B. Melton MD, PhD14 | Nicholas Ingraham MD15 Christopher J. Tignanelli MD | 13 | 14 1 Department of Medicine, Division of General Internal Medicine, University of Minnesota, Minneapolis, Minnesota, USA 2 Department of Medicine, Division of Endocrinology, University of North Carolina, Chapel Hill, North Carolina, USA 3 Humana Health Services Research Center, Miami University, Miami, Florida, USA 4 UnitedHealth Group Research and Development, Minnetonka, Minnesota, USA 5 Department of Medicine Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA 6 Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA 7 Department of Medicine, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA 8 Department of Medicine/Endocrinology, UT Southwestern Medical Center, Dallas, Texas, USA 9 Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, Texas, USA 10 Department of Medicine, Division of General Internal Medicine, John Hopkins, Baltimore, Maryland, USA 11 Department of Medicine, Weill Cornell Medicine, New York, New York, USA 12 Department of Emergency Medicine, Alameda County, Oakland, California, USA 13 Department of Epidemiology, Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis, Minnesota, USA 14 Department of Medicine, Division of Pulmonary Medicine, University of Minnesota, Minneapolis, Minnesota, USA 15 Department of Surgery, Division of Surgical Oncology, University of Minnesota, Minneapolis, Minnesota, USA Correspondence Carolyn T. Bramante, MD, MPH, 420 Delaware St SE, MMC 276, Minneapolis, MN 55455, USA. Email: bramante@umn.edu Abstract Observational studies suggest outpatient metformin use is associated with reduced mortality from coronavirus disease‐2019 (COVID‐19). Metformin is known to decrease interleukin‐6 and tumor‐necrosis factor‐α, which appear to contribute to morbidity in Funding information Agency for Healthcare Research and Quality, Grant/Award Number: K12HS026379; UMN Rapid Response Covid Grant, Grant/Award Number: UM 2020‐2231; COVID‐19. We sought to understand whether outpatient metformin use was associated with reduced odds of severe COVID‐19 disease in a large US healthcare data set. Retrospective cohort analysis of electronic health record (EHR) data that was pooled across This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. © 2021 The Authors. Journal of Medical Virology published by Wiley Periodicals LLC J Med Virol...