Association of metformin with susceptibility to COVID-19 in people with type 2 diabetes

Jingya Wang, Jennifer M Cooper, Krishna Gokhale, Dionisio Acosta-Mena, Samir Dhalla, Nathan Byne, Joht Singh Chandan, Astha Anand, Kelvin Okoth, Anuradhaa Subramanian, Mansoor N Bangash, Thomas Jackson, Dawit Zemedikun, Tom Taverner, Wasim Hanif, Sandip Ghosh, Parth Narendran, Konstantinos A Toulis, Abd A Tahrani, Rajendra SurenthirakumaranNicola J Adderley, Shamil Haroon, Kamlesh Khunti, Christopher Sainsbury, G Neil Thomas, Krishnarajah Nirantharakumar

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OBJECTIVE: Diabetes has emerged as an important risk factor for mortality from COVID-19. Metformin, the most commonly prescribed glucose-lowering agent, has been proposed to influence susceptibility to and outcomes of COVID-19 via multiple mechanisms. We investigated whether, in patients with diabetes, metformin is associated with susceptibility to COVID-19 and its outcomes.

RESEARCH DESIGN AND METHODS: We performed a propensity score-matched cohort study with active comparators using a large UK primary care dataset. Adults with type 2 diabetes patients and a current prescription for metformin and other glucose-lowering agents (MF+) were compared to those with a current prescription for glucose-lowering agents that did not include metformin (MF-). Outcomes were confirmed COVID-19, suspected/confirmed COVID-19, and associated mortality. A negative control outcome analysis (back pain) was also performed.

RESULTS: There were 29 558 and 10 271 patients in the MF+ and MF- groups, respectively, who met the inclusion criteria. In the propensity score-matched analysis, the adjusted hazard ratios for suspected/confirmed COVID-19, confirmed COVID-19, and COVID-19-related mortality were 0.85 (95% CI 0.67, 1.08), 0.80 (95% CI 0.49, 1.30), and 0.87 (95% CI 0.34, 2.20) respectively. The negative outcome control analysis did not suggest unobserved confounding.

CONCLUSION: Current prescription of metformin was not associated with the risk of COVID-19 or COVID-19-related mortality. It is safe to continue prescribing metformin to improve glycemic control in patients with.

Original languageEnglish
Article numberdgab067
Pages (from-to)1255-1268
Number of pages14
JournalJournal of Clinical Endocrinology and Metabolism
Issue number5
Early online date9 Feb 2021
Publication statusPublished - May 2021

Bibliographical note

© The Author(s) 2021. Published by Oxford University Press on behalf of the Endocrine Society.


  • Aged
  • COVID-19/complications
  • Cohort Studies
  • Diabetes Mellitus, Type 2/complications
  • Female
  • Humans
  • Hypoglycemic Agents/administration & dosage
  • Kaplan-Meier Estimate
  • Male
  • Metformin/administration & dosage
  • Middle Aged
  • Propensity Score
  • Retrospective Studies
  • SARS-CoV-2 infection
  • metformin
  • COVID-19
  • type 2 diabetes mellitus

ASJC Scopus subject areas

  • Biochemistry, medical
  • Endocrinology
  • Biochemistry
  • Clinical Biochemistry
  • Endocrinology, Diabetes and Metabolism


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