Prospective Test Performance of Nonfasting Biomarkers to Identify Dysglycemia in Children and Adolescents

Introduction: Test performance screening measures for dysglycemia have not been evaluated prospectively in youth. This study evaluated the prospective test performance of random glucose (RG), 1-hour nonfasting glucose challenge test (1-h GCT), Hemoglobin A1c (HbA1c), fructosamine (FA), and 1,5-Anhydroglucitol (1,5-AG) for identifying dysglycemia. Methods: Youth ages 8-17 years with overweight or obesity (body mass index, BMI, >= 85th percentile) without known diabetes completed nonfasting tests at baseline (n=176) and returned an average of 1.1 years later for two formal fasting 2-hour oral glucose tolerance tests. Outcomes included glucose-defined dysglycemia (fasting plasma glucose >= 100 mg/dL or 2-hour plasma glucose >= 140 mg/dL) or elevated HbA1c (>= 5.7%). Longitudinal test performance was evaluated using receiver operating characteristic (ROC) curves and calculation of area under the curve (AUC). Results: Glucose-defined dysglycemia, elevated HbA1c, and either dysglycemia or elevated HbA1c were present in 15 (8.5%), 11 (6.3%), and 23 (13.1%) participants at baseline, and 16 (9.1%), 18 (10.3%), and 28 (15.9%) participants at follow-up. For prediction of glucose-defined dysglycemia at follow-up, RG, 1-h GCT, and HbA1c had similar performance (0.68 (95% CI 0.55-0.80), 0.76 (95% CI 0.64-0.89), and 0.70 (95% CI 0.56-0.84)), while FA and 1,5-AG performed poorly. For prediction of HbA1c at follow-up, baseline HbA1c had strong performance (AUC 0.93 (95% CI 0.88-0.98)), RG had moderate performance (AUC 0.67 (0.54-0.79)), while 1-h GCT, FA, and 1,5-AG performed poorly. Conclusion: HbA1c and nonfasting glucose tests had reasonable longitudinal discrimination identifying adolescents at risk for dysglycemia, but performance depended on outcome definition.