Fasting and 2-h OGTT glucose along with HbA1c are used in clinical practice for diagnosing IGT and T2D, and in clinical trials for assessing eligibility. While previous studies found poor reproducibility of such measures in adults and youth at risk for dysglycemia, no studies have assessed group differences in reproducibility. We assessed reproducibility of glycemic measures in treatment-naïve youth and adults screened for RISE. Central laboratory measurements of plasma glucose and HbA1c from two standardized 2-h OGTTs completed 4 weeks apart were compared in 66 youth (mean age 14.2 y) and 354 adults (52.7 y) with IGT or recently diagnosed T2D, using ADA criteria. Between screening and baseline, mean coefficient of variation (CV) was lowest for HbA1c in both groups (Table). HbA1c variability was greater in youth than adults, whereas 2-h glucose variability was greater in adults. Status concordance was highest with HbA1c and lowest with 2-h glucose alone, and significantly lower in youth than adults using HbA1c alone. This variability produced discordant glycemic classification at screening vs. baseline in over 25% of participants. The variability and lack of classification concordance in youth and adults highlights the limitations of one-time testing for diagnostic classification in clinical practice and trials.

graphic
View largeDownload slide
Disclosure

A.H. Tjaden: None. S. Edelstein: None. S.A. Arslanian: None. E. Barengolts: None. S. Caprio: None. M. Cree-Green: None. A.A. Lteif: None. K.J. Mather: Advisory Panel; Self; Roche Diabetes Care. Research Support; Self; Abbott, Merck & Co., Inc., Novo Nordisk A/S, Sanofi. M. Savoye: None. A. Xiang: None. S.E. Kahn: Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Intarcia Therapeutics, Inc., Janssen Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk A/S. Consultant; Self; Neurimmune. Other Relationship; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk A/S. R. Consortium: None.

Funding

American Diabetes Association (1-14-RISE-01 to S.E.K.); National Institute of Diabetes and Digestive and Kidney Diseases

© 2019 by the American Diabetes Association.
2019
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals.org/content/license.