CGM-measured glucose values have a strong correlation with C-peptide, HbA1c and IDAAC, but do poorly in predicting C-peptide levels in the two years following onset of diabetes

Bruce Buckingham, Peiyao Cheng, Roy W. Beck, Craig Kollman, Katrina J. Ruedy, Stuart A. Weinzimer, Robert Slover, Andrew A. Bremer, John Fuqua, William Tamborlane, the Diabetes Research in Children Network (DirecNet) for the Diabetes Research in Children Network (DirecNet)

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Aims/hypothesis: The aim of this work was to assess the association between continuous glucose monitoring (CGM) data, HbA<inf>1c</inf>, insulin-dose-adjusted HbA<inf>1c</inf> (IDAA<inf>1c</inf>) and C-peptide responses during the first 2 years following diagnosis of type 1 diabetes. Methods: A secondary analysis was conducted of data collected from a randomised trial assessing the effect of intensive management initiated within 1 week of diagnosis of type 1 diabetes, in which mixed-meal tolerance tests were performed at baseline and at eight additional time points through 24 months. CGM data were collected at each visit. Results: Among 67 study participants (mean age [± SD] 13.3 ± 5.7 years), HbA<inf>1c</inf> was inversely correlated with C-peptide at each time point (p < 0.001), as were changes in each measure between time points (p < 0.001). However, C-peptide at one visit did not predict the change in HbA<inf>1c</inf> at the next visit and vice versa. Higher C-peptide levels correlated with increased proportion of CGM glucose values between 3.9 and 7.8 mmol/l and lower CV (p = 0.001 and p = 0.02, respectively) but not with CGM glucose levels <3.9 mmol/l. Virtually all participants with IDAA<inf>1c</inf> < 9 retained substantial insulin secretion but when evaluated together with CGM, time in the range of 3.9–7.8 mmol/l and CV did not provide additional value in predicting C-peptide levels. Conclusions/interpretation: In the first 2 years after diagnosis of type 1 diabetes, higher C-peptide levels are associated with increased sensor glucose levels in the target range and with lower glucose variability but not hypoglycaemia. CGM metrics do not provide added value over the IDAA<inf>1c</inf> in predicting C-peptide levels.

Original languageEnglish (US)
Pages (from-to)1167-1174
Number of pages8
JournalDiabetologia
Volume58
Issue number6
DOIs
StatePublished - Jun 1 2015

Keywords

  • Clinical diabetes
  • Clinical science
  • Devices

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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    Buckingham, B., Cheng, P., Beck, R. W., Kollman, C., Ruedy, K. J., Weinzimer, S. A., Slover, R., Bremer, A. A., Fuqua, J., Tamborlane, W., & for the Diabetes Research in Children Network (DirecNet), T. D. R. I. C. N. D. (2015). CGM-measured glucose values have a strong correlation with C-peptide, HbA1c and IDAAC, but do poorly in predicting C-peptide levels in the two years following onset of diabetes. Diabetologia, 58(6), 1167-1174. https://doi.org/10.1007/s00125-015-3559-y