The burden of calibrating continuous glucose monitoring (CGM) systems may be addressed by factory calibration (FC). We evaluated the accuracy of the "G6 FC" CGM System (Dexcom, Inc.) in adults ages 18+ and children ages 6-17 with type 1 diabetes. This was a prospective, non-randomized, multi-center, single-arm study that enrolled 76 subjects at 4 U.S. sites. Subjects participated in either 1 or 2 clinic sessions of varying duration, depending on age. System performance was evaluated in terms of percent accuracy with respect to YSI. Accuracy was characterized as the proportion of CGM values that were within ± 15%, ± 20% of their paired YSI values for glucose levels > 100 mg/dL or within ± 15 mg/dL, ± 20 mg/dL of YSI for glucose levels ≤ 100 mg/dL. The two-sided 95% bootstrapped confidence interval (CI) was calculated for its statistical significance. Accuracy was also measured by comparing the difference, absolute difference, relative difference and absolute relative difference of the G6 FC System with respect to YSI. The G6 FC System showed an overall percent % 20/20 accuracy of 93.9% (95% CI: 89.8, 97.1%) based on 3,532 matched pairs from 62 subjects (25 adults and 37 children). Similarly, the overall percent % 15/15 accuracy was 83.3% (95% CI: 76.7, 89.4%). The Day-1 and Day 10 percent % 20/20 accuracies were 92.2% and 92.5%, respectively; Day-1 and Day 10 mean absolute relative difference (MARD) values were 9.3% and 9.0%, respectively. The percent % 20/20 accuracy was 92.5% for adults and 96.2% for children. The MARD was 9.0% overall, 9.8% for adults, and 7.7% for children. Mean bias and mean relative difference were -8.3 mg/dL and -5.0%, respectively for overall; -10.9 mg/dL and -6.9% for adults; and -4.3 mg/dL and -2.1% for children. The G6 FC System showed high accuracy using multiple metrics for pediatric and adult subjects across days of wear, including Day 1. Elimination of the requirement for calibrations should improve the acceptability and utility of this novel CGM system.

Disclosure

X. Zhang: Employee; Self; Dexcom, Inc. T. Johnson: Employee; Self; Dexcom, Inc. D.A. Price: Employee; Self; Dexcom, Inc. A. Balo: Employee; Self; Dexcom, Inc..

© 2018 by the American Diabetes Association.
2018
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