Two 'Wonderful Advances' in CGM: The Dexcom G6 Pro and Freestyle Libre 2

Anne L. Peters, MD


September 29, 2020

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This transcript has been edited for clarity.

Today I'm going to discuss two new advances in continuous glucose monitoring (CGM).

Remember that there are two different kinds of continuous glucose monitors: professional and personal. Professional CGM is a blinded form of monitoring [where a device] is placed [on the patient] in the provider's clinic and worn by the patient for a discrete length of time. The sensor is then taken off and the data are analyzed retrospectively.

Personal CGM is the kind [of monitoring] where the patient owns the device. They get the device from their pharmacy, a distributor, or by mail order, and it's theirs. The sensors come to them and they pretty much wear the device continuously in order to get ongoing real-time data that allow them to adjust their insulin and make lifestyle modifications as needed.

But now, some nuances have changed.

The Dexcom G6 Pro

Dexcom has come out with its first version of a professional device — a device that is still put on in the office. But there are two ways that the Dexcom G6 Pro can be worn. One is the same blinded way, where it's put on in the office and started with a reader. The patient goes out, wears it, and the data are looked at when they come back. The second way is that in the office, instead of being turned on to be blinded, it can be turned on to be real-time, so that the patient can now see in an ongoing way what their glucose levels are. That information comes through the CLARITY [app], and it is on the patient's iPhone.

It's a lot like wearing a regular real-time Dexcom because they are seeing the data, but it's limited to a 10-day duration on the professional version. Instead of having a transmitter that is reused, the transmitter is just used for those 10 days. This is basically an office-based system that allows patients to have 10 days of real-time data or 10 days of blinded data that can be analyzed both by the patient and the healthcare professional in order to assess how a patient is doing.

The Freestyle Libre 2

The second advancement in CGM is the Freestyle Libre 2, which in my mind is really an advancement from the prior Libre. To your patients, it's going to act and seem a lot like the original Libre; it's still a round disc and you still have to swipe in order to get a glucose value. But now, on the reader, the patient can set alarms for a low glucose level and a high glucose level. There are no trend alarms — only alarms for an absolute level.

This device is different from the original Libre in that it does not couple to a smartphone; it must be coupled with a reader. The reader vibrates and/or makes a sound when the alarms are reached. A patient can set a low alarm, a high alarm, or both. They can also have an out-of-range signal loss alarm if they wish.

I think this is a wonderful advancement because I was always worried about patients not being alerted to being low. Now they can have this next to them at their bedside and it can give them an alert so they can know if they are going low. They still have to swipe to see what the actual number is, but to me, the notion of an alarm makes all the difference.

The other big change is that this is now more accurate. The Libre 2 was given the designation of an iCGM (integrated continuous glucose monitor) by the Food and Drug Administration. This means that it is at a higher standard and it now can be meshed with other devices because it's good enough to be used with an algorithm or a pump or anything else. The Dexcom was the first sensor to receive this designation, and now we have the Libre 2.

So the new Libre is more accurate and it now has an alarm for a high and low blood glucose level. These are great upgrades. Your patient may not like the fact that they have to carry the reader because it can no longer talk to a smartphone, but I think that you get so much more benefit from the alarms that it's worth carrying the reader. And in the future, it's going to talk to a smartphone as well.

It's really great that things are advancing. We now have the professional Dexcom G6 available to patients, which gives them at least a short-term, real-time or retrospective ability to look at their glucose levels, and the Libre 2, which expands the functionality of the original Libre system.

Anne L. Peters, MD, is a professor of medicine at the University of Southern California (USC) Keck School of Medicine and director of the USC clinical diabetes programs. She has published more than 200 articles, reviews, and abstracts, and three books, on diabetes, and has been an investigator for more than 40 research studies. She has spoken internationally at over 400 programs and serves on many committees of several professional organizations.

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