The Oral Glucose Tolerance Test: 100 Years Later

• Type of Material: Article
• Authors: Ram Jagannathan, Emory University; João Sérgio Neves, University of Porto; Brenda Dorcely, New York University; Stephanie T. Chung, National Institutes of Health; Kosuke Tamura, National Institutes of Health; Mary Rhee, Emory University; Michael Bergman, New York University
• Language: English
• Date: 2020-10-19
• Publisher: Dove Medical Press
• Publication Version: Final Published Version
• Copyright Statement: © 2020 Jagannathan et al.
• License: Creative Commons Attribution-Noncommercial 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.2147/DMSO.S246062
• Title of Journal or Parent Work: Diabetes Metabolic Syndrome and Obesity-Targets and Therapy
• Volume: 13
• Start Page: 3787
• End Page: 3805
• Grant/Funding Information: STC is supported by the Intramural Research Program of the NIH, The National Institute of Diabetes and Digestive and Kidney Diseases. Dr Mary Rhee reports clinical trial, site co-investigator for Boehringer Ingelheim, grants from National Institutes of Health, research support from Veterans Affairs (VA), outside the submitted work. MKR is supported in part by the NIH (U01 DK091958, U01 DK2U01DK098246, R03 AI133172, P30 DK111024, R21 AI156161), VA (VA I01 CX001737, IK2 RX002928), and Boehringer Ingelheim. MKR is also supported in part by the Veterans Health Administration (VA); this work is not intended to reflect the official opinion of the VA or the US government.
• Keywords: prediction; OGTT history; gestational diabetes; diabetes; shape index; glycated hemoglobin; pathophysiology; 1-h post-load glucose; OGTT
• Research Categories: Biology, Physiology; Health Sciences, Pathology

Abstract

For over 100 years, the oral glucose tolerance test (OGTT) has been the cornerstone for detecting prediabetes and type 2 diabetes (T2DM). In recent decades, controversies have arisen identifying internationally acceptable cut points using fasting plasma glucose (FPG), 2-h post-load glucose (2-h PG), and/or HbA1c for defining intermediate hyperglycemia (prediabetes). Despite this, there has been a steadfast global consensus of the 2-h PG for defining dysglycemic states during the OGTT. This article reviews the history of the OGTT and recent advances in its application, including the glucose challenge test and mathematical modeling for determining the shape of the glucose curve. Pitfalls of the FPG, 2-h PG during the OGTT, and HbA1c are considered as well. Finally, the associations between the 30-minute and 1-hour plasma glucose (1-h PG) levels derived from the OGTT and incidence of diabetes and its complications will be reviewed. The considerable evidence base supports modifying current screening and diagnostic recommendations with the use of the 1‐h PG. Measurement of the 1‐h PG level could increase the likelihood of identifying high-risk individuals when the pancreatic ß-cell function is substantially more intact with the added practical advantage of potentially replacing the conventional 2‐h OGTT making it more acceptable in the clinical setting.