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. 2025 Aug 1;48(8):1395-1399.
doi: 10.2337/dc25-0291.

Associations of CGM Metrics With Stimulated C-Peptide Measures in Youth With Recent-Onset Type 1 Diabetes

Anna Neyman  1   2 , Linda A DiMeglio  1 , Colleen Bauza  3 , Bruce Buckingham  4 , Mark A Clements  5 , Gregory P Forlenza  6 , Jennifer L Sherr  7 , Lauren Kanapka  3 , Roy W Beck  3 , Craig Kollman  3 , Shannon Beasley  8 , Erin Cobry  6 , Lisa Norlander  4 , Ryan McDonough  5 , Michelle Van Name  7 , Antoinette Moran  8 ; CLVer Study Group
Collaborators, Affiliations

Associations of CGM Metrics With Stimulated C-Peptide Measures in Youth With Recent-Onset Type 1 Diabetes

Anna Neyman et al. Diabetes Care. .

Abstract

Objective: Continuous glucose monitoring (CGM) measures could be a surrogate for stimulated C-peptide outcomes in type 1 diabetes trials.

Research design and methods: CGM and mixed-meal tolerance test-derived C-peptide measures at time points out to 52 weeks after diagnosis were compared in 103 children.

Results: At 52 weeks, CGM metrics moderately correlated with C-peptide area under the curve. The highest Spearman correlations were for time-in-range 70-180 mg/dL, time <70 mg/dL, and glucose coefficient of variation (0.45, -0.33, and -0.58, respectively; the multivariate model using these three metrics had a slightly higher correlation of 0.63). For predicting peak C-peptide concentrations ≥0.2 pmol/mL, this combination had a sensitivity of 68.4% and specificity of 75%.

Conclusions: CGM measures correlated with stimulated C-peptide measures; however, the strength of the correlations and sensitivity and specificity of CGM-derived measures were not great enough to replace C-peptide measures in clinical trials.

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Conflict of interest statement

Duality of Interest. L.A.D. reports receiving consulting or advisory fees from Abata Therapeutics, MannKind, Provention Bio, and Zealand Pharma and study supplies from Dexcom. B.B. reports receiving grants, personal fees, and/or nonfinancial support from Medtronic, Tandem Diabetes Care, Insulet, NovoNordisk, and Lilly, and reports his institution has received research funding from Medtronic, Tandem Diabetes Care, Beta Bionics, and Insulet. M.A.C. reports receiving personal fees from Glooko Inc and nonfinancial support from Dexcom and Abbott Diabetes Care. G.F.F. reports serving as a consultant, speaker, or advisory board member for Medtronic, Dexcom, Abbott, Tandem Diabetes Care, Insulet, Lilly, and Beta Bionics, and reports his institution has received funding on his behalf for research grants from Medtronic, Dexcom, Abbott, Tandem Diabetes Care, Insulet, Lilly, and Beta Bionics. J.L.S. reports receiving speaking honoraria from Lilly, Insulet, Medtronic, and Zealand Pharma; serving on advisory boards for Bigfoot Biomedical, Cecelia Health, Insulet, Medtronic Diabetes, Breakthrough T1D Fund, StartUp Health T1D Moonshot, and Vertex Pharmaceuticals; receiving consultant fees from Insulet and Medtronic; and that her institution has received research grant support from Medtronic and Insulet. R.W.B. reports his institution has received funding on his behalf as follows: grant funding and study supplies from Tandem Diabetes Care, Beta Bionics, and Dexcom; grant funding from Bigfoot Biomedical; study supplies from Medtronic, Ascencia, and Roche; consulting fees and study supplies from Lilly and NovoNordisk; and consulting fees from Insulet and Zucara Therapeutics. C.K. reports receiving grants from Dexcom and Tandem Diabetes Care. M.V.N. reports receiving research support from ProventionBio. A.M. reports serving on advisory boards from Dompé Farmaceutici SpA, ProventionBio, and Abata Therapeutics; serving on a data and safety monitoring board for NovoNordisk; and that her institution has received grant funding on her behalf from Abbott Diabetes, ProventionBio, Intrexon (now Precigen), and Caladrius Biosciences and study supplies from NovoNordisk, Medtronic, and Abbott Diabetes. No other potential conflicts of interest relevant to this article were reported.

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