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Research Paper|Volume 14, Issue 22|pp 8927—8943

The potential benefit of metformin to reduce delirium risk and mortality: a retrospective cohort study

Takehiko Yamanashi1,2,3, Zoe-Ella EM Anderson2, Manisha Modukuri2, Gloria Chang2, Tammy Tran2, Pedro S. Marra2, Nadia E. Wahba2, Kaitlyn J. Crutchley2, Eleanor J. Sullivan2, Sydney S. Jellison2, Katie R. Comp2, Cade C. Akers2, Alissa A. Meyer2, Sangil Lee4, Masaaki Iwata3, Hyunkeun R. Cho5, Eri Shinozaki6, Gen Shinozaki1,2
  • 1Stanford University School of Medicine, Department of Psychiatry and Behavioral Sciences, Palo Alto, CA 94305, USA
  • 2University of Iowa Carver College of Medicine, Department of Psychiatry, Iowa City, IA 52242, USA
  • 3Tottori University Faculty of Medicine, Department of Neuropsychiatry, Yonago-Shi, Tottori, Japan
  • 4University of Iowa Carver College of Medicine, Department of Emergency Medicine, Iowa City, IA 52242, USA
  • 5University of Iowa College of Public Health, Department of Biostatistics, Iowa City, IA 52242, USA
  • 6University of Iowa Carver College of Medicine, Department of Internal Medicine, Iowa City, IA 52242, USA
Received: July 26, 2022Accepted: October 27, 2022Published: November 17, 2022
https://doi.org/10.18632/aging.204393

Copyright: © 2022 Yamanashi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Purpose: Metformin has been reported to improve age-related disorders, including dementia, and to lower mortality. This study was conducted to investigate whether metformin use lower delirium risk, as well as long-term mortality.

Methods: In this retrospective cohort study, previously recruited 1,404 subjects were analyzed. The relationship between metformin use and delirium, and the relationship between metformin use and 3-year mortality were investigated.

Main findings: 242 subjects were categorized into a type 2 diabetes mellitus (DM)-without-metformin group, and 264 subjects were categorized into a DM-with-metformin group. Prevalence of delirium was 36.0% in the DM-without-metformin group, and 29.2% in the DM-with-metformin group. A history of metformin use reduced the risk of delirium in patients with DM (OR, 0.50 [95% CI, 0.32 to 0.79]) after controlling for confounding factors. The 3-year mortality in the DM-without-metformin group (survival rate, 0.595 [95% CI, 0.512 to 0.669]) was higher than in the DM-with-metformin group (survival rate, 0.695 [95% CI, 0.604 to 0.770]) (p=0.035). A history of metformin use decreased the risk of 3-year mortality after adjustment for confounding factors (HR, 0.69 [95% CI, 0.48 to 0.98]).

Conclusions: Metformin use may lower the risk of delirium and mortality in DM patients.