May 15, 2013

Head-to-Head Comparison of CGMs


head-to-headThe continuous glucose monitoring (CGM) systems of today are better than the yesteryear models. This study published in Diabetes Technology & Therapeutics compares the accuracy and reliability of the Dexcom G4, Freestyle Navigator, and the Medtronic Paradigm with Enlite.

The comparison evaluated 20 people with T1D and the experience with each of the CGMs in a hospital setting and at home.Before the participants were turned-out to try the CGMs at home, the study ensured that the calibration, glucose levels, and accuracy were on point.

Throughout the study, participants were required to perform at least 5 finger sticks, per day to calibrate blood glucose readings and interstitial fluid. Interstitial fluid (ISF) is the way CGMs take measurements every 5 minutes to ensure accuracy. It’s a correlated shadow of bG level.

The study measured the differences between ISF and bG. The average difference read n the hospital setting was: 14.3% for FreeStyle Navigator, 15.6% for Medtronic Paradigm with Enlitewas, and 18.2% for Dexcom G4.

At home, the CGMs read a difference of 16..7% for FreeStyle Navigator,  18.8% for Dexcom G4, and 23.6% for Medtronic Paradigm with Enlitewas.

Of interest, and not advised by the CGM manufacturer is the amount of days the sensors will function. The Dexcom G4 works up to 10 days. The FreeStyle Navigator will work up to 8 days, and the Medtronic Paradigm with Enlitewas works for up to 8 days.

Final results show that the Dexcom G4 and the Medtronic Paradigm with Enlitewas were comparable in their accuracy. The Medtronic Paradigm with Enlitewas was less accurate than the Dexcom G4 or FreeStyle Navigatorl.

It’s important to realize that a CGM is trend reporting, not glucose monitoring. You must have a bG meter to effectively use a CGM.

The accuracy of CGMs today is better than it was 5 years ago. Moreover, the lifetime of each sensor may surpass the recommendations of the manufacturer. This is not to dare you to overextend your sensors. This is just to say that if push comes to shove, your sensor will keep doing the job for another day or two, if need be.

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