Thirty-Minute Post-load Glucose Could Be a Useful Screening Measure for Abnormal Oral Glucose Tolerance Test Response in Adolescents with Obesity

BACKGROUND: With the growing obesity epidemic, subjecting every child with obesity to a 2-hour oral glucose tolerance test (OGTT) is impractical. Instead, 30-minute plasma glucose (PG), which reflects the acute phase of insulin secretion, might be a useful measure in the initial assessment of such individuals. Our study aimed to evaluate the optimal cutoff of 30-minute PG in predicting abnormal OGTT response and to compare the predictive value of this cutoff with that of the previously reported values from a combination of non-fasting parameters. METHODS: For this study, 332 overweight or obese pediatric individuals who had undergone the OGTT under the Department of Pediatrics and Adolescent Medicine, Queen Mary Hospital, Hong Kong, from 2012 to 2018 were included. The optimal cutoff of 30-minute PG for prediction of abnormal OGTT response was determined using a receiver operating characteristics curve, and the positive predictive value (PPV) was evaluated. RESULTS: There were 180 males (54.2%) and the mean age of the included individuals was 15.4±2.3 years. A 30-minute PG ≥9.2 mmol/L predicts abnormal OGTT response with the best combination of sensitivity and specificity. The PPV for abnormal OGTT response at this cutoff was 45%. Addition of this 30-minute PG cutoff to non-fasting parameters, including glycated hemoglobin, abnormal alanine transaminase, and family history of diabetes, resulted in an improved PPV of 70% for abnormal OGTT response. CONCLUSION: Addition of 30-minute PG to non-fasting parameters improved the clinical utility in identifying high-risk individuals for abnormal OGTT response.