Standard blood glucose screening tools were designed largely around adult physiology, yet the pediatric obesity epidemic is creating an urgent need for better early-warning indicators in children. This small but methodologically careful study suggests that continuous glucose monitoring, specifically how much time a young person spends within tight glucose ranges, may add meaningful signal beyond conventional markers for identifying prediabetes in obese adolescents.
Eighty-four youth with obesity (ages 10–18, mean BMI ~32.8 kg/m²) wore a Freestyle Libre 2 sensor for two weeks while also undergoing a formal oral glucose tolerance test. Investigators compared two CGM-derived metrics—time in tight range (TITR) of 70–140 mg/dL and 70–120 mg/dL—between participants classified as having normal glucose tolerance versus prediabetes. Both TITR thresholds were significantly lower in the prediabetes group (p < 0.05), while HbA1c and post-load glucose area under the curve were significantly elevated. Notably, no other CGM metrics beyond the tight-range variables showed statistically significant differences between groups, pointing to TITR as the most sensitive free-living glucose signal in this population.
This work enters a contested space. Pediatric HbA1c has known reliability limitations due to higher red-cell turnover in adolescents, and fasting glucose can miss the postprandial dysregulation that often appears first in youth-onset insulin resistance. CGM offers a two-week window into real-world glucose dynamics, potentially capturing excursions that a single clinic visit cannot. However, with only 84 participants, this remains an exploratory, hypothesis-generating study rather than definitive evidence. The cohort skewed young (mean age ~12.6 years) and included no control group of lean youth. It also cannot establish whether lower TITR causally precedes or simply accompanies prediabetes onset. Replication in larger, more diverse cohorts with longitudinal follow-up is essential before TITR could inform clinical screening protocols. Still, as an incremental proof-of-concept, the findings position TITR as a promising adjunct metric deserving prospective evaluation.