Accuracy of a 15-day Factory-Calibrated Continuous Glucose Monitoring System With Improved Sensor Design

Abstract

Background:

This study evaluates the performance of a 15-day factory-calibrated continuous glucose monitoring sensor used in FreeStyle Libre 2 Plus (Libre 2 Plus) and FreeStyle Libre 3 Plus (Libre 3 Plus) Systems, featuring an improved sensor design to reduce vitamin C interference.

Methods:

Participants aged 2 years and above were enrolled for this study at seven sites in the United States. Depending on their age and bodyweight, participants attended up to three in-clinic sessions where venous blood was obtained for comparator measurement. For 2- to 5-year-olds, only capillary comparator data were collected. Participants aged 11 years and older underwent supervised glycemic manipulation to achieve glucose levels across the sensor’s measurement range. Performance measures included the proportion of continuous glucose monitoring (CGM) values within ±20%/±20 mg/dL of comparator glucose values and mean absolute relative difference (MARD) between CGM and comparator values.

Results:

Of the total 332 participants enrolled in the study, 149 adults and 124 pediatric participants (ages 6-17 years) had paired data for analysis against YSI comparator. Percentages within ±20 mg/dL/20% were 94.2% and 94.0%, and MARDs were 8.2% and 8.1% for the adults and pediatric participants, respectively. For 12 pediatric participants of 2 to 5 years, the percentage within ±20 mg/dL/20% was 86.6%, with an MARD of 11.2% against self-monitoring of blood glucose (SMBG) comparator. The sensor performed well in the hypoglycemic range, with 97.1% and 98.0% of results within ±15 mg/dL of the YSI comparator for the adult and pediatric participants, respectively.

Conclusions:

The Libre 2 Plus and Libre 3 Plus Systems provide accurate glucose results across the dynamic range during the 15-day sensor wear period.