Accuracy of a 14-Day Factory-Calibrated Continuous Glucose Monitoring System With Advanced Algorithm in Pediatric and Adult Population With Diabetes

Background: In this study, we evaluated the analytical performance of the second-generation factory-calibrated FreeStyle Libre Flash Glucose Monitoring (FreeStyle Libre 2) System compared to plasma venous blood glucose reference, Yellow Springs Instrument 2300 (YSI). Methods: The study enrolled participants aged four and above with type 1 or type 2 diabetes at seven sites in the United States. Adult participants (18+ years) participated in three in-clinic sessions and pediatric participants (4-17years) participated in up to two in-clinic sessions stratified to provide data for days 1, 2, 3, 7, 8, 9, 12, 13, or 14 of sensor wear. Participants aged 11+ underwent supervised glycemic manipulation during in-clinic sessions to achieve glucose levels across the measurement range of the System. Performance evaluation included accuracy measures such as the proportion of continuous glucose monitoring (CGM) values that were within +/- 20% or +/- 20mg/dL of reference glucose values, and bias measures such as the mean absolute relative difference (MARD) between CGM and reference values. Results: Data from the 144 adults and 129 pediatric participants were analyzed. Percent of sensor results within +/- 20%/20mg/dL of YSI reference were 93.2% and 92.1%, and MARD was 9.2% and 9.7% for the adults and pediatric participants, respectively. The System performed well in the hypoglycemic range, with 94.3% of the results for the adult population and 96.1% of the data for pediatric population being within 15mg/dL of the YSI reference. The time lag was 2.4 +/- 4.6minutes for adults and 2.1 +/- 5.0minutes for pediatrics. Conclusions: The System demonstrated improved analytical accuracy performance across the dynamic range during the 14-day sensor wear period as compared to the previous-generation device.

Automated summary

This study evaluated the analytical performance of the second-generation factory-calibrated FreeStyle Libre 2 system compared to the YSI reference. The results showed that the system performed well in terms of accuracy and bias during the 14-day sensor wear period. It demonstrated excellent performance in the hypoglycemic range.