Improvement of Glycemic Control by Metformin Is Associated With Frequency of Defecation Before Treatment in Patients With Type 2 Diabetes Mellitus

Kunio Hieshima, Seigo Sugiyama, Akira Yoshida, Noboru Kurinami, Tomoko Suzuki, Kaori Otsuka, Fumio Miyamoto, Keizo Kajiwara, Katsunori Jinnouchi, Tomio Jinnouchi, Hideaki Jinnouchi


Background: It was recently reported that metformin induces glucose excretion in the terminal ileum. This study reassessed the ability of metformin to promote defecation and its relationship with the glycated hemoglobin (HbA1c) level in patients with type 2 diabetes mellitus (T2DM).

Methods: We retrospectively assessed the frequency of defecation (FD) in patients with T2DM who were admitted to our hospital for glycemic control between April 2017 and March 2022. We examined the FD associated with initiation of metformin or a sodium-glucose cotransporter-2 inhibitor (SGLT2i) by calculating the change in FD after starting treatment (DeltaFD). Next, we compared the FD variables (DeltaFD, the FD ratio and FD before and after starting treatment) and the change in glycated hemoglobin (DeltaHbA1c) at 1.5 and 6 months after discharge between the two treatment groups with no change in medications except for minor adjustments in the insulin dose.

Results: Fifty-five patients were included (metformin group, n = 30; SGLT2i group, n = 25). The mean FD increased significantly after the maximum dose was reached in the metformin group (from 0.70 0.19 to 0.83 0.18 times/day; P = 0.001) but not in the SGLT2i group. Surprisingly, there was no significant relationship between DeltaFD or the FD ratio before and after starting treatment and the DeltaHbA1c in either treatment group. However, there was a significant correlation of FD before and after starting metformin with the DeltaHbA1c (r = -0.467, P = 0.009 and r = -0.509, P = 0.004, respectively). Multivariate analysis found a significant correlation of FD before and after starting metformin with DeltaHbA1c (P < 0.05). However, there was no correlation of FD with DeltaHbA1c before or after starting an SGLT2i.

Conclusions: Metformin improves HbA1c in patients with T2DM in an FD-associated manner but not in an FD change-associated manner. Given that DeltaHbA1c was associated with FD both after and before starting metformin, we suggest that the effects of this agent may be influenced by the pretreatment FD as well as conventional dose dependence. However, metformin did increase the FD, but the reason for this phenomenon is currently unknown.

J Endocrinol Metab. 2023;13(4):153-163


Frequency of defecation; Metformin; Type 2 diabetes mellitus

Full Text: HTML PDF

Browse  Journals  


Journal of Clinical Medicine Research

Journal of Endocrinology and Metabolism

Journal of Clinical Gynecology and Obstetrics


World Journal of Oncology

Gastroenterology Research

Journal of Hematology


Journal of Medical Cases

Journal of Current Surgery

Clinical Infection and Immunity


Cardiology Research

World Journal of Nephrology and Urology

Cellular and Molecular Medicine Research


Journal of Neurology Research

International Journal of Clinical Pediatrics



Journal of Endocrinology and Metabolism, bimonthly, ISSN 1923-2861 (print), 1923-287X (online), published by Elmer Press Inc.                     
The content of this site is intended for health care professionals.
This is an open-access journal distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License, which permits unrestricted
non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons Attribution license (Attribution-NonCommercial 4.0 International CC-BY-NC 4.0)

This journal follows the International Committee of Medical Journal Editors (ICMJE) recommendations for manuscripts submitted to biomedical journals,
the Committee on Publication Ethics (COPE) guidelines, and the Principles of Transparency and Best Practice in Scholarly Publishing.

website:   editorial contact:
Address: 9225 Leslie Street, Suite 201, Richmond Hill, Ontario, L4B 3H6, Canada

© Elmer Press Inc. All Rights Reserved.

Disclaimer: The views and opinions expressed in the published articles are those of the authors and do not necessarily reflect the views or opinions of the editors and Elmer Press Inc. This website is provided for medical research and informational purposes only and does not constitute any medical advice or professional services. The information provided in this journal should not be used for diagnosis and treatment, those seeking medical advice should always consult with a licensed physician.