OGTT Glucose Response Curves, Insulin Sensitivity, and β-Cell Function in RISE: Comparison Between Youth and Adults at Randomization and in Response to Interventions to Preserve β-Cell Function
Authors: Silva A. Arslanian, Laure El ghormli, Joon Young Kim, Ashley H. Tjaden, Elena Barengolts, Sonia Caprio, Tamara S. Hannon, Kieren J. Mather, Kristen J. Nadeau, Kristina M. Utzschneider, Steven E. Kahn, David A. Ehrmann, Karla A. Temple, Abby Rue, Elena Barengolts, Babak Mokhlesi, Eve Van Cauter, Susan Sam, M. Annette Miller, Steven E. Kahn, Karen M. Atkinson, Jerry P. Palmer, Kristina M. Utzschneider, Tsige Gebremedhin, Abigail Kernan-Schloss, Alexandra Kozedub, Brenda K. Montgomery, Emily J. Morse, Kieren J. Mather, Tammy Garrett, Tamara S. Hannon, Amale Lteif, Aniket Patel, Robin Chisholm, Karen Moore, Vivian Pirics, Linda Pratt, Kristen J. Nadeau, Susan Gross, Philip S. Zeitler, Jayne Williams, Melanie-Cree Green, Yesenia Garcia Reyes, Krista Vissat, Silva A. Arslanian, Kathleen Brown, Nancy Guerra, Kristin Porter, Sonia Caprio, Mary Savoye, Bridget Pierpont, Thomas A. Buchanan, Anny H. Xiang, Enrique Trigo, Elizabeth Beale, Fadi N. Hendee, Namir Katkhouda, Krishan Nayak, Mayra Martinez, Cortney Montgomery, Xinhui Wang, Sharon L. Edelstein, John M. Lachin, Ashley N. Hogan, Santica Marcovina, Jessica Harting, John Albers, Dave Hill, Peter J. Savage, Ellen W. Leschek
Journal: Diabetes Care (2021)

OBJECTIVE We examined the glucose response curves (biphasic [BPh], monophasic [MPh], incessant increase [IIn]) during an oral glucose tolerance test (OGTT) and their relationship to insulin sensitivity (IS) and β-cell function (βCF) in youth versus adults with impaired glucose tolerance or recently diagnosed type 2 diabetes. RESEARCH DESIGN AND METHODS This was both a cross-sectional and a longitudinal evaluation of participants in the RISE study randomized to metformin alone for 12 months or glargine for 3 months followed by metformin for 9 months. At baseline/randomization, OGTTs (85 youth, 353 adults) were categorized as BPh, MPh, or IIn. The relationship of the glucose response curves to hyperglycemic clamp–measured IS and βCF at baseline and the change in glucose response curves 12 months after randomization were assessed. RESULTS At randomization, the prevalence of the BPh curve was significantly higher in youth than adults (18.8% vs. 8.2%), with no differences in MPh or IIn. IS did not differ across glucose response curves in youth or adults. However, irrespective of curve type, youth had lower IS than adults (P &amp;lt; 0.05). βCF was lowest in IIn versus MPh and BPh in youth and adults (P &amp;lt; 0.05), yet compared with adults, youth had higher βCF in BPh and MPh (P &amp;lt; 0.005) but not IIn. At month 12, the change in glucose response curves did not differ between youth and adults, and there was no treatment effect. CONCLUSIONS Despite a twofold higher prevalence of the more favorable BPh curve in youth at randomization, RISE interventions did not result in beneficial changes in glucose response curves in youth compared with adults. Moreover, the typical β-cell hypersecretion in youth was not present in the IIn curve, emphasizing the severity of β-cell dysfunction in youth with this least favorable glucose response curve.