Continuous Glucose Monitoring System Offers Improved Accuracy

Frequent use of continuous glucose monitoring systems is associated with improved glycemic outcomes in persons with diabetes, but the need for calibrations and sensor insertions are often barriers to adoption.

A newly improved, factory-calibrated, continuous glucose monitoring (CGM) system provided accurate glucose readings for 10 days (240 hours) and removed a number of clinical barriers to widespread CGM use, such as acetaminophen interference and complicated adjustments.

Scientists at the University of Colorado Denver (Aurora, CO, USA) and their colleague tested the accuracy of the improved G6 CGM system, which includes a thinner and smaller transmitter, predictive low glucose alert, sensor membrane to block acetaminophen, and 10-day sensor wear. The current study enrolled 151 youth (age 6 to 17) and 139 adults with type 1 and 2 diabetes from 11 sites within the USA.

Youth participants returned for one clinic session of six hours, and adults for three clinic sessions of up to three hours, during which CGM readings were compared with venous glucose concentrations in a laboratory setting. Glucose levels were manipulated for the 202 participants over the age of 13 to determine that the G6 CGM system, was adequately covering the entire reportable 40-400 mg/dL range. Performance evaluation included the proportion of CGM values that were within ±20% of reference glucose values greater than 100 mg/dL or within ±20 mg/dL of reference glucose values ≤100 mg/dL (%20/20), the analogous (%15/15), and the mean absolute relative difference (MARD, expressed as a percentage) between temporally matched CGM and reference values.

The data from 262 study participants (21,569 matched CGM reference pairs) were analyzed. The overall %15/15, %20/20, and MARD were 82.4%, 92.3%, and 10.0%, respectively. Matched pairs from 134 adults and 128 youth of ages 6–17 years were similar with respect to %20/20 (92.4% and 91.9%) and MARD (9.9% and 10.1%). Overall %20/20 values on days 1 and 10 of sensor wear were 88.6% and 90.6%, respectively. The system's “Urgent Low Soon” (predictive of hypoglycemia within 20 minutes) hypoglycemia alert was correctly provided 84% of the time within 30 minutes before impending biochemical hypoglycemia (<70 mg/dL). The 10-day sensor survival rate was 87%.

The authors concluded that the new factory-calibrated G6 real-time CGM system provides accurate readings for 10 days and removes several clinical barriers to broader CGM adoption. The study was published online on June 1, 2018, in the journal Diabetes Technology & Therapeutics.

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University of Colorado Denver