@article{26d16f7f8c174553bce529500118109a,
title = "Associations of HbA1c with the timing of C-peptide responses during the oral glucose tolerance test at the diagnosis of type 1 diabetes",
abstract = "Background: In new onset type 1 diabetes (T1D), overall C-peptide measures such as area under the curve (AUC) C-peptide and peak C-peptide are useful for estimating the extent of β-cell dysfunction, and for assessing responses to intervention therapy. However, measures of the timing of C-peptide responsiveness could have additional value. Objectives: We assessed the contribution of the timing of C-peptide responsiveness during oral glucose tolerance tests (OGTTs) to hemoglobin A1c (HbA1c) variation at T1D diagnosis. Methods: We analyzed data from 85 individuals <18 years with OGTTs and HbA1c measurements at diagnosis. Overall [AUC and peak C-peptide] and timing measures [30-0 minute C-peptide (early); 60 to 120 minute C-peptide sum-30 minutes (late); 120/30 C-peptide; time to peak C-peptide] were utilized. Results: At diagnosis, the mean (±SD) age was 11.2 ± 3.3 years, body mass index (BMI)-z was 0.4 ± 1.1, 51.0% were male. The average HbA1c was 43.54 ± 8.46 mmol/mol (6.1 ± 0.8%). HbA1c correlated inversely with the AUC C-peptide (P < 0.001), peak C-peptide (P < 0.001), early and late C-peptide responses (P < 0.001 each), and 120/30 C-peptide (P < 0.001). Those with a peak C-peptide occurring at ≤60 minutes had higher HbA1c values than those with peaks later (P = 0.003). HbA1c variance was better explained with timing measures added to regression models (R2 = 11.6% with AUC C-peptide alone; R2 = 20.0% with 120/30 C-peptide added; R2 = 13.7% with peak C-peptide alone, R2 = 20.4% with timing of the peak added). Similar associations were seen between the 2-hour glucose and the C-peptide measures. Conclusions: These findings show that the addition of timing measures of C-peptide responsiveness better explains HbA1c variation at diagnosis than standard measures alone.",
keywords = "C-peptide, HbA1c, OGTT, glycemia, type 1 diabetes",
author = "{Type 1 Diabetes Trial Net and Diabetes Prevention Trial-Type-1 (DPT-1) Study Groups} and Ismail, {Heba M.} and Carmella Evans-Molina and DiMeglio, {Linda A.} and Becker, {Dorothy J.} and Ingrid Libman and Sims, {Emily K.} and David Boulware and Herold, {Kevan C.} and Lisa Rafkin and Jay Skyler and Cleves, {Mario A.} and Jerry Palmer and Sosenko, {Jay M.}",
note = "Funding Information: information National Institute of Allergy and Infectious Diseases; National Institute of Diabetes and Digestive and Kidney Diseases; Eunice Kennedy Shriver National Institute of Child Health and Human Development, Grant/Award Numbers: UC4 DK106993, U01 DK107014, U01 DK107013, U01 DK106994, U01 DK106984, U01 DK103282, U01 DK103266, U01 DK103153, U01 DK103180, U01 DK085509, U01 DK085499, U01 DK085476, U01 DK085466, U01 DK085465, U01 DK085461, U01 DK061058, U01 DK061042, U01 DK061034, U01 DK061010Members of the Type 1 Diabetes TrialNet Study Group and TrialNet Affiliate Centers are listed in the online only (electronic Supporting Information). The Type 1 Diabetes TrialNet Study Group is a clinical trials network currently funded by the National Institutes of Health (NIH) through the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Allergy and Infectious Diseases, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, through the cooperative agreements U01 DK061010, U01 DK061034, U01 DK061042, U01 DK061058, U01 DK085461, U01 DK085465, U01 DK085466, U01 DK085476, U01 DK085499, U01 DK085509, U01 DK103180, U01 DK103153, U01 DK103266, U01 DK103282, U01 DK106984, U01 DK106994, U01 DK107013, U01 DK107014, UC4 DK106993, and the Juvenile Diabetes Research Foundation International (JDRF). The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the NIH or the JDRF. Funding Information: Members of the Type 1 Diabetes TrialNet Study Group and TrialNet Affiliate Centers are listed in the online only (electronic Supporting Information). The Type 1 Diabetes TrialNet Study Group is a clinical trials network currently funded by the National Institutes of Health (NIH) through the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Allergy and Infectious Diseases, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, through the cooperative agreements U01 DK061010, U01 DK061034, U01 DK061042, U01 DK061058, U01 DK085461, U01 DK085465, U01 DK085466, U01 DK085476, U01 DK085499, U01 DK085509, U01 DK103180, U01 DK103153, U01 DK103266, U01 DK103282, U01 DK106984, U01 DK106994, U01 DK107013, U01 DK107014, UC4 DK106993, and the Juvenile Diabetes Research Foundation International (JDRF). The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the NIH or the JDRF. Publisher Copyright: {\textcopyright} 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd",
year = "2019",
month = jun,
doi = "10.1111/pedi.12845",
language = "English (US)",
volume = "20",
pages = "408--413",
journal = "Pediatric Diabetes",
issn = "1399-543X",
publisher = "Blackwell Munksgaard",
number = "4",
}