Glucose patterns during the OGTT and risk of future diabetes in an urban Indian population: the CARRS study

• Authors: Adam Hulman, Aarhus University; Unjali Gujral, Emory University; K.M. Venkat Narayan, Emory University; Rajendra Pradeepa, World Health Organization; Deepa Mohan, World Health Organization; Ranjit Mohan Anjana, World Health Organization; Viswanathan Mohan, World Health Organization; Kristine Faerch, Steno Diabetes Center; Daniel Witte, Aarhus University
• Journal Title: Diabetes Research and Clinical Practice
• Volume: Volume 126
• Publisher: Elsevier | 2017-04-01, Pages 192-197
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.diabres.2017.01.009
• Subjects: Health Sciences, Public Health; Health Sciences, Nutrition
• Keywords: Science & Technology; Life Sciences & Biomedicine; Endocrinology & Metabolism; Type 2 diabetes; Asian Indian; Oral glucose tolerance test; Diabetes physiology; BETA-CELL DYSFUNCTION; PLASMA-GLUCOSE; ASIAN INDIANS; INSULIN SENSITIVITY; DYSGLYCEMIA; TOLERANCE; RESISTANCE; PREDICTOR; LEVEL

Abstract

Traditionally, fasting and 2-hour post challenge plasma glucose have been used to diagnose diabetes. However, evidence indicates that clinically relevant pathophysiological information can be obtained by adding intermediate time-points to a standard oral glucose tolerance test (OGTT). Methods We studied a population-based sample of 3666 Asian Indians without diabetes from the CARRS-Chennai Study, India. Participants underwent a three-point (fasting, 30-min, and 2-h) OGTT at baseline. Patterns of glycemic response during OGTT were identified using latent class mixed-effects models. After a median follow-up of two years, participants had a second OGTT. Logistic regression adjusted for diabetes risk factors was used to compare risk of incident diabetes among participants in different latent classes. Results We identified four latent classes with different glucose patterns (Classes 1–4). Glucose values for Classes 1, 2, and 4 ranked consistently at all three time-points, but at gradually higher levels. However, Class 3 represented a distinct pattern, characterized by high 30-min (30 minPG), normal fasting (FPG) and 2-h (2hPG) plasma glucose, moderately high insulin sensitivity, and low acute insulin response. Approximately 22% of participants were categorized as Class 3, and had a 10-fold risk of diabetes compared to the group with the most favorable glucose response, despite 92.5% of Class 3 participants having normal glucose tolerance (NGT) at baseline. Conclusions Elevated 30 minPG is associated with high risk of incident diabetes, even in individuals classified as NGT by a traditional OGTT. Assessing 30 minPG may identify a subgroup of high-risk individuals who remained unidentified by traditional measures.