Skip to main content
Top

03-02-2025 | Metformin | Original Research

Inpatient Metformin Utilization and Post-hospitalization Clinical Outcomes: An Observational Cohort Study

Authors: Robert J. Gallo, MD, Shoutzu Lin, MS, Daniel Z. Fang, MD, Peter A. Glassman, MBBS, MSc, Anju Sahay, PhD, Paul A. Heidenreich, MD, MS

Published in: Journal of General Internal Medicine

Login to get access

Abstract

Background

Metformin is the first-line treatment for diabetes, with multiple long-term benefits. However, there is limited evidence for its use in the inpatient setting, and clinical guidelines have historically recommended holding oral diabetes medications during acute hospitalization. While studies have not found evidence of harm from continuing metformin during hospitalization, withholding may lead to unnecessary insulin prescriptions, which in turn may lead to hypoglycemia events after discharge and other associated complications.

Objective

To investigate the association between metformin use during hospitalization and post-hospitalization outcomes.

Design

Observational cohort study from January 2016 to January 2022, emulating a target trial.

Participants

Adults with type 2 diabetes admitted to a Veterans Health Administration hospital for common medical conditions.

Interventions

Continuation of an outpatient metformin prescription during hospitalization.

Main Measures

Hypoglycemia within 90 days of discharge. Secondary outcomes included insulin prescriptions at discharge, 90-day readmissions, and 90-day mortality.

Key Results

The propensity-matched cohort included 67,162 hospitalizations, equally split between those who did and did not have metformin continued during hospitalization. Within 90 days of hospital discharge, those that received metformin had lower risk of hypoglycemia (1.5% vs 1.8%; OR 0.83, 95% CI 0.73–0.93; p = 0.003), readmissions (29.4% vs 30.6%; OR 0.96, 95% CI 0.92–1.00; p= 0.03), and mortality (6.4% vs 7.4%; OR 0.86, 95% CI 0.80–0.92; p <0.001). Patients receiving metformin also had lower risk of insulin prescriptions at discharge (18.5% vs 20.3%; OR 0.89, 95% CI 0.84–0.95; p<0.001).

Conclusions

Continuation of metformin during hospitalization for patients with type 2 diabetes was associated with decreased risk of post-hospitalization insulin prescriptions and 90-day hypoglycemia, readmissions, and mortality. These findings question clinical guideline recommendations to hold metformin during hospitalization.
Appendix
Available only for authorised users
Literature
1.
go back to reference Maruthur NM, Tseng E, Hutfless S, et al. Diabetes Medications As Monotherapy or Metformin-based Combination Therapy for Type 2 Diabetes: A Systematic Review and Meta-analysis. Ann Intern Med. 2016;164(11). https://doi.org/10.7326/M15-2650 Maruthur NM, Tseng E, Hutfless S, et al. Diabetes Medications As Monotherapy or Metformin-based Combination Therapy for Type 2 Diabetes: A Systematic Review and Meta-analysis. Ann Intern Med. 2016;164(11). https://​doi.​org/​10.​7326/​M15-2650
12.
go back to reference Aalen OO, Johansen S. An empirical transition matrix for nonhomogeneous Markov chains based on censored observations. Scandinavian Journal of Statistics. Published online 1978:141-150. Aalen OO, Johansen S. An empirical transition matrix for nonhomogeneous Markov chains based on censored observations. Scandinavian Journal of Statistics. Published online 1978:141-150.
13.
go back to reference Pishgar F, Greifer N, Leyrat C, Stuart E. MatchThem:: matching and weighting after multiple imputation. arXiv preprint arXiv:200911772. Published online 2020. Pishgar F, Greifer N, Leyrat C, Stuart E. MatchThem:: matching and weighting after multiple imputation. arXiv preprint arXiv:200911772. Published online 2020.
14.
go back to reference Greifer N, Greifer MN. Package ‘cobalt.’ R Package Version. 2020;4. Greifer N, Greifer MN. Package ‘cobalt.’ R Package Version. 2020;4.
17.
go back to reference ACR Committee on Drugs and Contrast Media. ACR Manual On Contrast Media. American College of Radiology; 2023. ACR Committee on Drugs and Contrast Media. ACR Manual On Contrast Media. American College of Radiology; 2023.
18.
go back to reference Gallo RJ, Fang DZ, Heidenreich PA. Administrative Coding Versus Laboratory Diagnosis of Inpatient Hypoglycemia. Diabetes Care. 2023;46(6):e126-e127.CrossRefPubMed Gallo RJ, Fang DZ, Heidenreich PA. Administrative Coding Versus Laboratory Diagnosis of Inpatient Hypoglycemia. Diabetes Care. 2023;46(6):e126-e127.CrossRefPubMed
Metadata
Title
Inpatient Metformin Utilization and Post-hospitalization Clinical Outcomes: An Observational Cohort Study
Authors
Robert J. Gallo, MD
Shoutzu Lin, MS
Daniel Z. Fang, MD
Peter A. Glassman, MBBS, MSc
Anju Sahay, PhD
Paul A. Heidenreich, MD, MS
Publication date
03-02-2025
Publisher
Springer International Publishing
Published in
Journal of General Internal Medicine
Print ISSN: 0884-8734
Electronic ISSN: 1525-1497
DOI
https://doi.org/10.1007/s11606-025-09384-y

Keynote series | Spotlight on menopause

Menopause can have a significant impact on the body, with effects ranging beyond the endocrine and reproductive systems. Learn about the systemic effects of menopause, so you can help patients in your clinics through the transition.   

Prof. Martha Hickey
Dr. Claudia Barth
Dr. Samar El Khoudary
Developed by: Springer Medicine
Watch now

Keynote webinar | Spotlight on adolescent vaping

Growing numbers of young people are using e-cigarettes, despite warnings of respiratory effects and addiction. How can doctors tackle the epidemic, and what health effects should you prepare to manage in your clinics?

Prof. Ann McNeill
Dr. Debbie Robson
Benji Horwell
Developed by: Springer Medicine
Watch now

Keynote webinar | Spotlight on modern management of frailty

Frailty has a significant impact on health and wellbeing, especially in older adults. Our experts explain the factors that contribute to the development of frailty and how you can manage the condition and reduce the risk of disability, dependency, and mortality in your patients.

Prof. Alfonso Cruz-Jentoft
Prof. Barbara C. van Munster
Prof. Mirko Petrovic
Developed by: Springer Medicine
Watch now

A quick guide to ECGs

Improve your ECG interpretation skills with this comprehensive, rapid, interactive course. Expert advice provides detailed feedback as you work through 50 ECGs covering the most common cardiac presentations to ensure your practice stays up to date. 

PD Dr. Carsten W. Israel
Developed by: Springer Medizin
Start the cases

At a glance: The STEP trials

A round-up of the STEP phase 3 clinical trials evaluating semaglutide for weight loss in people with overweight or obesity.

Developed by: Springer Medicine
Read more