Continuous Glucose Monitoring Identifies Youth with Prediabetes at Risk for Glycemic Progression

Pediatric prediabetes is common among youth with obesity, yet most do not progress to type 2 diabetes, and many regress to normoglycemia. Youth-onset type 2 diabetes has a severe course not well predicted by degree of adiposity or hemoglobin A1c (HbA1c) alone. This study used continuous glucose monitoring (CGM) to characterize glycemic patterns in youth with prediabetes and to determine whether baseline CGM metrics identify those at highest risk for HbA1c progression over 6 months.

Youth aged 10-18 years with obesity and HbA1c 5.7%-6.4% were enrolled in a prospective 6-month observational cohort study, with baseline and follow-up assessments including HbA1c and 14 days of CGM wear. CGM metrics were derived using the R iglu package. Changes over time and associations with follow-up HbA1c and HbA1c change were analyzed using paired t-tests and PRESS-based forward-selected linear regression models, adjusting for clinical covariates.

Among 29 youth with prediabetes, HbA1c and most CGM metrics remained stable over 6 months, with 32% regressing to normoglycemia. One participant progressed to HbA1c 6.5% who demonstrated markedly elevated baseline CGM glycemic variability and hyperglycemia. While multiple baseline CGM metrics were associated with follow-up HbA1c and HbA1c change in univariable analyses, PRESS-based multivariable models identified time spent above 140 mg/dL as the strongest and only consistent independent predictor of both higher follow-up HbA1c and worsening glycemic trajectory.

CGM metrics outperformed HbA1c in predicting short-term glycemic progression in youth with prediabetes, supporting CGM as a promising adjunctive tool for early risk stratification.