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Updated: May 6, 2026

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
Published on: April 7, 2020
Performance of three simultaneously used rtCGM systems around a physically active weekend camp in adults with type 1
Sabrina Sanfilippo1,2, Ulrike Thurm2, Mats Renfordt2
1Exercise Physiology, Training & Training Therapy Research Group, Department of Human Movement Sciences, Sport, and Health, University of Graz, Graz, Austria.
Aims:
Real-time continuous glucose monitoring (rtCGM) is crucial to diabetes management in type 1 diabetes (T1D), but its accuracy decreases during glucose fluctuations triggered by physical activity and exercise.
Materials And Methods:
Twenty adults with T1D (9 females; age 50 ± 12 years; HbA1c 6.6 ± 0.5%) participated in this study, which included a 3-day lab phase where three group exercise sessions (each lasting 90 min) were performed, followed by a 4-day home phase. Participants were required to wear a Dexcom G7 (Dexcom), FreeStyle Libre 3 (Abbott), and Simplera (Medtronic) rtCGM simultaneously. From 8:00 AM (initial measurement) to 10:00 PM (final measurement), duplicate capillary blood glucose measurements were taken at 2-h intervals using the Contour Next One glucometer (Ascensia Diabetes Care) and recorded in addition to the actual displayed sensor glucose values. The performance of the rtCGM systems was evaluated by means of median absolute relative difference (MedARD) and interquartile range [IQR] against the reference blood glucose. Absolute relative differences (|ARD|) of the three rtCGMs were analysed using the Kruskal-Wallis test (p < 0.05).
Results:
Overall, the MedARD [IQR] for Dexcom G7 was 8.4% [3.6-14.0] (723 comparison points), for Libre 3 7.5% [3.1-13.4] (723 comparison points), and Simplera 13.8% [6.9-22.5] (719 comparison points). No significant differences were found between Libre 3 versus Dexcom G7 (p = 0.35). A significant difference was found for Dexcom G7 versus Simplera and Libre 3 versus Simplera (p < 0.0001).
Conclusions:
Dexcom G7 and FreeStyle Libre 3 showed very high accuracy, which could not be found for the Simplera rtCGM system.
Clinical Registration:
German Clinical Trial Register, DRKS: DRKS00035836.
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