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ADA: CGM Comparisons — Advances, Pitfalls, and Clinical Relevance

Jul 14, 2018
 

Overview from a presentation at the 2018 American Diabetes Associations 78th Scientific Sessions.

Attendees were provided with a detailed review and evaluation of findings that affect clinical and economic outcomes related to current FDA-approved products for “point in time” glucometers and also the devices for continuous monitoring of blood glucose levels, specifically in type 1 diabetes. Of note is that all study sets reviewed had less than 30 participants and may therefore be considered as not statistically significant.

Glucometers

All evidence reviewed was of glucometers with in-home use as these products were not officially approved for hospital use. The result was that a disappointing 46.4% passed the 2013 International Standards for Organization (ISO) Standards.

Of interest was that outcomes were suggestive of bias as evaluations of glucometers varied most significantly when the study was performed by a competitor, next by the manufacturer itself and then by an independent source. Glucometers are technique-dependent and individualized use in home would anticipate further variances of technique from ideal circumstances expected in lab testing.

Continuous Glucose Monitors (CGM)

The discussion shared trends related to glucose variability from basal rate by 46–55% in studies of 13 and 20 participants respectively, during the Dawn Phenomenon observed in approximately 50% of participants. Specifically a MARD derivation set and validation study suggests the need for ongoing assessment of these devices in the real world.

Challenges cited compared six weeks’ use related to warm-up time, calibration requirements, sensor life, and interferences shown in the chart below:

 

CGM Dexcom G5 Dexcom G6* Freestyle Libre Pro Senseonics

Eversense

Warmup time 2 hours 2 hours 1 hour 24 hours
Calibration Requirements 2 x/day Not Required none 2x/day
Sensor Life 7 days 10 Days 14 days 90 days US

180 days Europe

Interferences Tylenol Vitamin C, ASA

*(was not included in discussion)

Conclusions

Accuracy cannot be directly compared across CGM devices, however, the Eversense achieved the most favorable MARD during clinical studies followed by the Dexcom G-5 with the Libre Pro performing poorly in the hypoglycemic range.

The session started with a discussion on accuracy of blood glucose monitors and it was found that less than 50% of meters tested met the ISO standards. Next there was a discussion on the Eversense Implantable continuous glucose monitoring system. This sensor will be implanted in the upper arm and worn for 180 days. The MARD is 9.4% with a 78% survival rate for 180 days.

The transmitter is the size of a quarter and is removed for showers. It has a rechargeable battery that is charged for 15 minutes every two days and will require two calibrations a day. The next discussion was an accuracy comparison of the Dexcom G-5, Abbott Libre Pro, and Eversense CGM. The Eversense achieved the lowest MARD during clinical studies followed by the Dexcom G-5 with the Libre Pro performing poorly in the hypoglycemic range.

Submitted by Michele Laine MSN-ARNP, CDE and Sandy Pieschel, RN, CDE

Summary of presentation at American Diabetes Association Annual Meeting and conference June 22, 2018