Initial Experience with a Novel 21-Day Continuous Glucose Monitoring System in Pediatric Type 1 Diabetic Patients: A Two-Center Initial Accuracy Evaluation

Abstract _______________________________________________________________________________________________________________ Background. All currently marketed factory-calibrated continuous glucose monitoring (CGM) systems are licensed for a maximum wear time of 14 days. We report the first clinical experience with the Perlanova (Instara-1) CGM system, a factory-calibrated device with an extended 21-day sensor wear time, in a pediatric population with type 1 diabetes (T1D). Methods. In a two-center retrospective evaluation, sensors were applied to pediatric T1D patients aged 4–18 years and worn for up to 21 days. CGM readings were compared against contemporaneous capillary (fingerstick) self-monitoring of blood glucose (SMBG) reference values. Paired data points were generated by matching each reference measurement to the nearest CGM value within a predefined time window. The primary endpoint was the overall mean absolute relative difference (MARD); secondary endpoints included the MARD trajectory across the 21-day wear period, MARD stratified by glycaemic range, Bland–Altman agreement, and consensus error-grid distribution. Results. A total of 1,523 paired data points from 32 pediatric T1D patients (median age 13 years, range 4–18) were analysed. Using a ±10-minute matching window, the overall MARD was 8.6% (median absolute relative difference 3.8%). Point-of-care agreement was high (87.5% within ±15/15 and 93.1% within ±20/20). CGM and reference glucose were strongly correlated (r = 0.963), and 98.9% of paired points fell within consensus error-grid zones A+B. Bland–Altman analysis showed a small negative bias (−5.9 mg/dL; 95% limits of agreement −50.2 to +38.4 mg/dL). Accuracy was preserved throughout the 21-day wear period, with daily MARD remaining largely within the 5–8% band and no progressive deterioration before day 21. Conclusion. This first-in-class experience indicates that the 21-day Perlanova CGM system provides clinically acceptable accuracy in pediatric T1D patients, maintained across the full extended wear period. These preliminary findings support larger confirmatory studies using a venous/YSI reference standard.