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World J Diabetes. Jun 15, 2021; 12(6): 786-793
Published online Jun 15, 2021. doi: 10.4239/wjd.v12.i6.786
Oral glucose tolerance test in diabetes, the old method revisited
Feng Yu Kuo, Kai-Chun Cheng, Yingxiao Li, Juei-Tang Cheng
Feng Yu Kuo, Cardiovascular Center, Veterans General Hospital, Kaohsiung 82445, Taiwan
Kai-Chun Cheng, Department of Pharmacy, College of Pharmacy and Health Care, Tajen University, Pingtung 90741, Taiwan
Kai-Chun Cheng, Pharmacological Department of Herbal Medicine and Department of Psychosomatic Internal Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan
Yingxiao Li, Department of Nursing, Tzu Chi University of Science and Technology, Hualien 973302, Taiwan
Juei-Tang Cheng, Department of Medical Research, Chi-Mei Medical Center, Tainan 71004, Taiwan
Author contributions: Kuo FY and Cheng KC designed the article; Kuo FY and Li Y collected the references and prepared the manuscript; Cheng JT revised the manuscript for important intellectual content; all authors read and approved the final manuscript.
Conflict-of-interest statement: No conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Juei-Tang Cheng, PhD, Additional Professor, Department of Medical Research, Chi-Mei Medical Center, No. 901 Zhonghua Road, Yong Kang District, Tainan 71004, Taiwan. jtcheng5503@gmail.com
Received: January 14, 2021
Peer-review started: January 14, 2021
First decision: February 12, 2021
Revised: February 24, 2021
Accepted: May 19, 2021
Article in press: May 19, 2021
Published online: June 15, 2021
Processing time: 141 Days and 4.1 Hours
Abstract

The oral glucose tolerance test (OGTT) has been widely used both in clinics and in basic research for a long time. It is applied to diagnose impaired glucose tolerance and/or type 2 diabetes mellitus in individuals. Additionally, it has been employed in research to investigate glucose utilization and insulin sensitivity in animals. The main aim of each was quite different, and the details are also somewhat varied. However, the time or duration of the OGTT was the same, using the 2-h post-glucose load glycemia in both, following the suggestions of the American Diabetes Association. Recently, the use of 30-min or 1-h post-glucose load glycemia in clinical practice has been recommended by several studies. In this review article, we describe this new view and suggest perspectives for the OGTT. Additionally, quantification of the glucose curve in basic research is also discussed. Unlike in clinical practice, the incremental area under the curve is not suitable for use in the studies involving animals receiving repeated treatments or chronic treatment. We discuss the potential mechanisms in detail. Moreover, variations between bench and bedside in the application of the OGTT are introduced. Finally, the newly identified method for the OGTT must achieve a recommendation from the American Diabetes Association or another official unit soon. In conclusion, we summarize the recent reports regarding the OGTT and add some of our own perspectives, including machine learning and others.

Keywords: Oral glucose tolerance test; Impaired glucose tolerance; Glucose Utilization; Type 2 diabetes; Area under the curve

Core Tip: Oral glucose tolerance test (OGTT) is a useful tool that has been applied from the last century to now. It is used to diagnose impaired glucose tolerance and/or type 2 diabetes mellitus in individuals. Basic research also applied it to investigate the glucose utilization and insulin sensitivity in animals. However, the main aim of each is quite different, and the details are also somewhat varied. In addition to the merits of OGTT in bench and bedside, variations between clinical practice and basic research are also discussed. Notably, recent reports have recommended that the time for OGTT be shorter in individuals. This conclusion needs to be confirmed officially in advance by diabetes associations. This new method is also required to be clarified in animal research. Additionally, perspectives of OGTT application are also conducted in this review including machine learning. Therefore, this report suggests a new way for OGTT practice in the future.