Flash glucose monitoring in children under 4 years of age: a prospective evaluation of the Freestyle Libre 2 in a pediatric type 1 diabetes population

BACKGROUND. Continuous glucose monitoring (CGM) is becoming the standard of care for children with type 1 diabetes (T1D), yet data on its use in children under 4 years old remain limited. FreeStyle Libre 2 (FSL2) is approved for use from the age of 4, but there is a clinical need for use in younger age groups.

OBJECTIVE. To evaluate the accuracy and safety of the FSL2 system when used off-label in children aged 1–4 years with T1D.

MATERIALS AND METHODS. The study included 20 children with T1D (mean age 2.8±0.7 years, diabetes duration 1.2±0.8 years, HbA1c 7.1±1.4%). Participants consecutively used two FSL2 sensors over a 28-day period. Accuracy was assessed by comparing FSL2 data to reference capillary blood glucose measurements (≥6 times daily). Analyses included mean absolute relative difference (MARD), agreement rates, and distribution across zones of the Parkes consensus error grid.

RESULTS. A total of 2,554 paired measurements were analyzed. Overall MARD was 11.5% (95% CI: 10.6–12.3%). Agreement rates: 74.6% of readings were within ±15%/15 mg/dL, and 84.2% within ±20%/20 mg/dL. A total of 99.9% of readings fell within Zones A+B of the consensus error grid. MARD remained stable over the 14-day sensor wear period (11.9%, 11.1%, 11.7% in the initial, middle and final periods of use). The average sensor wear time was 285.7±95.9 hours. No serious adverse events were reported; local skin reactions were mild and resolved fully without any treatment.

CONCLUSION. FSL2 demonstrated clinically acceptable accuracy and a high safety profile in children aged 1–4 years with T1D. The findings support potential extension of FSL2 use in this age group to improve glycemic control and family quality of life.

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