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. 2021 Mar;15(2):287-293.
doi: 10.1177/1932296819895022. Epub 2019 Dec 17.

Comparative Accuracy Analysis of a Real-time and an Intermittent-Scanning Continuous Glucose Monitoring System

Manuela Link  1 , Ulrike Kamecke  1 , Delia Waldenmaier  1 , Stefan Pleus  1 , Arturo Garcia  2 , Cornelia Haug  1 , Guido Freckmann  1
Affiliations

Comparative Accuracy Analysis of a Real-time and an Intermittent-Scanning Continuous Glucose Monitoring System

Manuela Link et al. J Diabetes Sci Technol. 2021 Mar.

Abstract

Background: Currently, two different types of continuous glucose monitoring (CGM) systems are available: real time (rt) CGM systems that continuously provide glucose values and intermittent-scanning (is) CGM systems. This study compared accuracy of an rtCGM and an isCGM system when worn in parallel.

Methods: Dexcom G5 Mobile (DG5) and FreeStyle Libre (FL) were worn in parallel by 27 subjects for 14 days including two clinic sessions with induced glucose excursions. The percentage of CGM values within ±20% or ±20 mg/dL of the laboratory comparison method results (YSI 2300 STAT Plus, YSI Inc., Yellow Springs, OH, United States; glucose oxidase based) or blood glucose meter values and mean absolute relative difference (MARD) were calculated. Consensus error grid and continuous glucose error grid analyses were performed to assess clinical accuracy.

Results: Both systems displayed clinically accurate readings. Compared to laboratory comparison method results during clinic sessions, DG5 had 91.5% of values within ±20%/20 mg/dL and a MARD of 9.5%; FL had 82.5% of scanned values within ±20%/20 mg/dL and an MARD of 13.6%. Both systems showed a lower level of performance during the home phase and when using the blood glucose meter as reference.

Conclusion: The two systems tested in this study represent two different principles of CGM. DG5 generally provided higher accordance with laboratory comparison method results than FL.

Keywords: accuracy; continuous glucose monitoring; mean absolute relative difference; performance; sensor.

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Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: GF is general manager of the IDT (Institut für Diabetes-Technologie Forschungs- und Entwicklungsgesellschaft mbH an der Universität Ulm, Ulm, Germany), which carries out clinical studies on the evaluation of BG meters and medical devices for diabetes therapy on its own initiative and on behalf of various companies. GF/IDT have received speakers’ honoraria or consulting fees from Abbott, Ascensia, Bayer, Dexcom, LifeScan, Menarini Diagnostics, Metronom Health, Novo Nordisk, Roche, Sanofi, Sensile and Ypsomed. ML, UK, DW, SP, and CH are employees of IDT. AG is employee of Dexcom, Inc.

Figures

Figure 1.
Figure 1.
Differences between continuous glucose monitoring (top: Dexcom G5 Mobile, bottom: scanned FreeStyle Libre) and glucose oxidase based comparison method values. Dotted lines indicate the ±20 mg/dL/20% range.
Figure 2.
Figure 2.
Distribution of values within ±20 mg/dL/20% of glucose oxidase based comparison method values (left: Dexcom G5 Mobile, right: scanned FreeStyle Libre) between individual subjects (n = 27).
See this image and copyright information in PMC

References

    1. FDA advisory panel votes to recommend non-adjunctive use of Dexcom G5 mobile CGM. Diabetes Technol Ther. 2016;18(8):512-516. - PubMed
    1. Shapiro AR. Nonadjunctive use of continuous glucose monitors for insulin dosing: is it safe? J Diabetes Sci Technol. 2017;11(4):833-838. - PMC - PubMed
    1. International Organization for Standardization. In vitro diagnostic medical devices – Measurement of quantities in biological samples – Metrological traceability of values assigned to calibrators and control materials. EN ISO. 17511:2003. 2003.
    1. Liu D, Moberg E, Kollind M, Lins PE, Adamson U, Macdonald IA. Arterial, arterialized venous, venous and capillary blood glucose measurements in normal man during hyperinsulinaemic euglycaemia and hypoglycaemia. Diabetologia. 1992;35(3):287-290. - PubMed
    1. Kropff J, van Steen SC, deGraaff P, Chan MW, van Amstel RBE, DeVries JH. Venous, arterialized-venous, or capillary glucose reference measurements for the accuracy assessment of a continuous glucose monitoring system. Diabetes Technol Ther. 2017;19(11):609-617. - PubMed

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