(46) Metformin Use and Risk for COVID-19 Infection and Severe COVID-19 Outcomes

Sunday, August 28, 2022

8:00 AM – 1:45 PM CEST

Location: Hall C

Publication Number: 1091

Presenting Author(s)

Sascha Dublin, MD, PhD
– Senior Scientific Investigator, Kaiser Permanente Washington Health Research Institute, University of Washington, Seattle, Washington, Seattle, Washington, United States

Co-Author(s)

Jennifer Kuntz, PhD
– Kaiser Permanente Center for Health Research, Portland, Oregon, United States
James Floyd, MD, MS
– Associate Professor, Department of Medicine, University of Washington, Seattle, WA, United States
Rod Walker, MS
– Biostatistician III, Kaiser Permanente Washington Health Research Institute, Seattle, WA, United States
Stephen Fortmann, MD
– Distinguished Investigator, Senior Director Science Programs, Kaiser Permanente Center for Health Research, Portland, OR, United States
Elizabeth Bayliss, MD, MSPH
– Senior Scientific Investigator, Institute for Health Research, Kaiser Permanente Colorado, Aurora, CO, United States
Susan Shortreed, PhD
– Senior Scientific Investigator, Kaiser Permanente Washington Health Research Institute, Seattle, WA, United States
Laura Harrington, PhD, MPH
– Assistant Investigator, Kaiser Permanente Washington Health Research Institute, Seattle, WA, United States
Mi Lee, MPH
– Data Report and Analytics Consultant III, Biostatistics, Kaiser Permanente Center for Health Research, Portland, OR, United States
Ladia Albertson-Junkans, MPH
– Data Analytics and Reporting Consultant, Kaiser Permanente Washington Health Research Institute, Seattle, WA, United States
John Powers, MS
– Biostatistician, Institute for Health Research, Kaiser Permanente Colorado, Aurora, CO, United States
Sharon Fuller, BA
– Programmer, Kaiser Permanente Washington Health Research Institute, Seattle, WA, United States

Background: Metformin is a glucose-lowering drug recommended as first-line treatment for diabetes mellitus (DM). Several observational studies have linked metformin use prior to or at the time of COVID-19 infection to reduced infection severity and mortality risk among people with DM.

Objectives: To evaluate the association between current metformin use and risk of (1) COVID-19 infection and (2) severe COVID-19-related outcomes among people with DM.

Methods: We conducted a retrospective cohort study among adult (≥18 years) members of 3 integrated health care systems in the US (Kaiser Permanente Colorado, Northwest, and Washington) who were continuously enrolled for 6 months as of 2/29/20 with no prior COVID-19 infection. Our study population was people with DM, as identified through International Classification of Disease (ICD)-9/ICD-10 diagnosis, hemoglobin A1c (HbA1c) ≥ 6.5%, or outpatient dispensing of DM medications. We identified COVID-19 infections between cohort entry and 2/28/21 through positive polymerase chain reaction SARS-CoV-2 testing results, inpatient ICD-10 diagnosis codes for COVID-19, and death certificates listing COVID-19 as cause of death. We defined severe COVID-19 outcomes as COVID-19 hospitalization with invasive mechanical ventilation or COVID-19-related death. We used repeated measures logistic regression to estimate the association between a time-varying measure of current metformin use (versus no use) and odds of COVID-19 infection, adjusting for other glucose-lowering medication use (insulin, sulfonylurea, other DM medications), demographics, calendar time, presence of comorbid conditions, body mass index, and DM severity measures (DM type, complications, and HbA1c levels). Using similar methods, we estimated the odds of severe COVID-19 outcomes.

Results: We identified 142,340 adults with DM as of 2/29/2020, of which 52% were women and 68% self-reported their race/ethnicity as non-Hispanic white. Mean age was 63 years and 44% were receiving metformin. Analyses included 6,019 COVID-19 infections and 471 severe COVID-19 outcomes. We did not find sufficient evidence to support an association between current metformin use and the odds of COVID-19 infection (adjusted odds ratio (aOR)=0.95; 95% confidence interval (CI): 0.89-1.00) or severe COVID-19 outcomes (aOR=0.83; 95% CI: 0.67-1.02) among people with DM.

Conclusions: Our study did not support an association between metformin use and COVID-19 infection or severity among people with DM. Our results contrast with those of several prior studies. Differences may be due to variations in the methods used to define and capture metformin use, DM severity measures, and COVID-19 outcomes.