What question did this study set out to answer?

This research aims to evaluate the agreement between continuous glucose monitoring (CGM) and plasma glucose metrics during glucose tolerance tests in youth-onset type 2 diabetes.

June 7, 2026

2937-LB: Agreement of Continuous Glucose Monitoring during Oral Glucose and Mixed-Meal Tests

Key Points

This research aims to evaluate the agreement between continuous glucose monitoring (CGM) and plasma glucose metrics during glucose tolerance tests in youth-onset type 2 diabetes.
Interim analysis included 24 youth-onset type 2 diabetes (Y-T2DM) and 9 healthy controls.
Participants underwent a 120-minute oral glucose tolerance test (OGTT) and a 300-minute mixed meal test (MMT).
Statistical analyses included Welch’s t-test, Bland-Altman analysis, and Lin’s Concordance Correlation Coefficient.
CGM AUC exceeded plasma AUC during OGTT (mean bias 2446 mg/dL·120 min, P<0.01) and MMT (3524 mg/dL·300 min, P<0.01).
Lower concordance between CGM and plasma AUC for OGTT (r=0.78) compared to MMT (r=0.93).
CGM-derived mDI-woI estimates were less than plasma (bias: -0.19 mL/mU/min) with poor concordance (r=0.46).

Abstract

Introduction and Objective: Continuous Glucose Monitoring (CGM) is widely used for glycemic management in type 2 diabetes and increasingly used in persons at risk for diabetes. CGM-derived glucose estimates may differ by up to 15% from venous plasma glucose, and performance in youth-onset type 2 diabetes (Y-T2DM), particularly during rapid glucose excursions, is not well characterized. We evaluated agreement between CGM and plasma glucose-derived metrics during an oral glucose tolerance test (OGTT) and mixed meal test (MMT) using glucose area under the curve (AUC) and model-derived disposition index without insulin (mDI-woI). Methods: This interim analysis included 24 Y-T2DM and 9 healthy controls who underwent a 120-minute 75g OGTT and 300-minute liquid MMT. CGM (Dexcom G7) was worn during testing. Glucose AUC was calculated using the trapezoidal rule. mDI-woI, an integrated measure of β-cell function, was derived by fitting OGTT data to an insulin sensitivity and secretion model in MATLAB. Statistical analyses included Welch’s t-test, Bland-Altman analysis and Lin’s Concordance Correlation Coefficient in R. Results: Participants were 20±3 years old (mean±SD), 52% female, BMI 36.3±11.0 kg/m2, and HbA1c 6.8±2.5%. Y-T2DM had higher BMI and HbA1c than controls (P0.05). CGM AUC exceeded plasma AUC during OGTT (mean 95% CI bias 2446 1017, 3875 mg/dL·120 min, P0.01) and MMT (3524 1073, 5974 mg/dL·300 min, P0.01). AUC bias did not differ between Y-T2D and controls for OGTT and MMT (P0.05). Concordance between CGM and plasma AUC was lower for OGTT (r=0.78) than MMT (r=0.93). mDI-woI estimates were lower using CGM versus plasma glucose (bias: -0.19 -0.27, -0.10 10-4 mL/mU/min) with poor concordance (r=0.46). Conclusion: During standardized metabolic testing, CGM-derived metrics overestimated glucose relative to plasma. Concordance varied by physiological context and was lower for OGTT-derived measures than MMT. Poor agreement highlights important limitations of CGM-derived metrics for modeling glucose dynamics and diabetes risk in youth. Disclosure N. Sala: None. M.M. Gaydos: None. I.N. Kacker: None. N.A. Macheret: None. S.L. Cantor: None. A. Sherman: None. J. Ha: None. N. Rangos: None. L. Mabundo: None. N. Malandrino: None. S. Chung: None. Funding National Institute of Diabetes & Digestive & Kidney Diseases, Z99 DK 999999

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2937-LB: Agreement of Continuous Glucose Monitoring during Oral Glucose and Mixed-Meal Tests

Key Points

Abstract

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