The Oral Glucose Tolerance Test: 100 Years Later

Abstract

Ram Jagannathan,1 João Sérgio Neves,2,3 Brenda Dorcely,4 Stephanie T Chung,5 Kosuke Tamura,6 Mary Rhee,7 Michael Bergman8 1Division of Hospital Medicine, Emory University School of Medicine, Atlanta, GA, USA; 2Department of Surgery and Physiology, Cardiovascular Research and Development Center, Faculty of Medicine, University of Porto, Porto, Portugal; 3Department of Endocrinology, Diabetes and Metabolism, Sa&uppertilde;o Joa&uppertilde; o University Hospital Center, Porto, Portugal; 4NYU Grossman School of Medicine, Division of Endocrinology, Diabetes, Metabolism, New York, NY 10016, USA; 5Diabetes, Obesity, and Endocrinology Branch, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA; 6Social Determinants of Obesity and Cardiovascular Risk Laboratory, Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; 7Emory University School of Medicine, Department of Medicine, Division of Endocrinology, Metabolism, and Lipids, Atlanta VA Health Care System, Atlanta, GA 30322, USA; 8NYU Grossman School of Medicine, NYU Diabetes Prevention Program, Endocrinology, Diabetes, Metabolism, VA New York Harbor Healthcare System, Manhattan Campus, New York, NY 10010, USACorrespondence: Ram JagannathanDivision of Hospital Medicine, Emory University School of Medicine, Atlanta, GA 30322, USAEmail [email protected]: 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.Keywords: OGTT history, OGTT, glycated hemoglobin, diabetes, gestational diabetes, pathophysiology, 1-h post-load glucose, prediction, shape index

Keywords

• ogtt history
• ogtt
• glycated hemoglobin
• diabetes
• gestational diabetes
• pathophysiology
• 1-h post-load glucose
• prediction
• shape index;