Did Dexcom make the right G6 choice?

I’ve been following the recent news about the FDA’s approval for Dexcom to market its new G6 continuous glucose monitor. I even listened to two podcasts interviewing Dexcom CEO Kevin Sayer recorded in the last few days.

The big issue for many, especially those who pay cash for their Dexcom CGMs, is that the G6 features a hard shut-off at 10 days. We won’t be able to restart the sensors like many have done over the years with the G4/G5 systems.

Why did Dexcom choose this absolute 10-day service life? Kevin Sayer, CEO of Dexcom, said that the company had to make that choice in order for the FDA to certify the G6 as a “no calibration required” system and that the user could make treatment decisions based on the CGM reading. Mr. Sayer said that this 10-day absolute shut-off was required by the FDA.

Now I realize that no normal person prefers to poke his/her finger as much as we diabetics have over the years. Getting a CGM that releases us from this onerous task is attractive. I get that.

What I’m wondering, however, is if Dexcom made a good trade-off. I, for one, would much prefer the ability to restart a CGM sensor for a second or even third session. I am lucky enough to enjoy good insurance coverage. Others who pay cash for their CGM use may very well be priced out of using the G6. A hard 10-day G6 shutoff will restrict access to many in our community.

I think Dexcom made a bad trade. I used to prick my fingertips 12-15 times per day. Fingersticking once or twice per day for calibration doesn’t seem like much of a cost to enable sensor restarts.

I’ve been using a Dexcom CGM since 2009. I will likely hang back with my G4 system instead of upgrading to the G6.



It seems like a bad trade off to me–what’s the big deal about calibrating once a day?–but as I posted elsewhere I think there’s more to it. I assume it also has to do with non-Medtronic pump makers integrating with Dexcom CGM for their closed loop systems. Because those systems involve giving the CGM direct automated control over insulin dosing, accuracy–and thus calibration–takes on a much higher importance both in the eyes of the FDA and in practice. The MdT Guardian approach to this is to make the calibrations mandatory for running automode: if you don’t calibrate, the CGM readings stop and the pump kicks you out of auto until you do. It’s a fairly elaborate process to get it all started up again, especially when it happens at stupid-o’clock in the a.m. (which it inevitably does). So having a system that doesn’t require calibration is a distinct marketing advantage with regard to looping. But even those of us used to getting 14-21 days out of a sensor know that they will eventually start behaving erratically, which again has much greater potential consequences in a closed-loop system. I presume that’s why they have to declare a fairly conservative hard deadline of ten days.

For me, I’ve had my go at auto mode and I’m not eager to return to it, so I’ll stick with my G5s for now.


I’m sure this figured into Dexcom’s decision. It seems to me that this safety related decision is more appropriately considered when the full system, including the insulin pump, is proposed.

I’m also thinking that the user could make a choice at the outset of each G6 sensor session. S/he could proceed down the daily calibration/sensor restart path or the no cals/no sensor no-restart path.

I know that many people with diabetes work at Dexcom, but I wonder about the users’ role, if any, in this decision. I am always suspicious when a med-tech manufacturer tries to shift responsibility onto the FDA.

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I’ll be very interested to see what Dexcom does when the G6 comes to other countries. In the US, it seems the majority of people have insurance coverage for part or all of the cost of a CGM. In Canada and likely most other countries, the vast majority of people pay for their CGM entirely out of pocket. So this decision could have much more far-reaching consequences in other countries than it does in the US.

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I understand the financial attractiveness of this decision for Dexcom. I also understand the G6 was developed with future closed-loop systems in mind. IMO, Dexcom seems to be forgetting that, at least in the US, not everyone will want to use closed-loop, & many will be unable to afford it. With the uncertainty of the future of health insurance in this country, I view that as a big risk. Pumps & CGMs alone are expensive enough, & already out of reach of so many. How much more expensive will closed-loop systems be?


That will change the market dynamic. I’m sorry to see Dexcom take this path. Sayer says he wants to widen access to CGM technology but this move doesn’t back up his words.

If the price were to drop significantly, then I’d give his words more weight. I have a feeling that a box of three G6 sensors (a fixed 30-day supply) will end up costing about the same as four G4/G5 sensors (a nominal 28-day supply).


What he probably means is he wants to get more insurance coverage and/or government coverage. Not that he wants to make these technologies affordable to the user.

A box of G4/G5 sensors is a 90-120 day supply for me. :frowning:

I certainly won’t be upgrading if this limitation is also true for Canada.


Avoiding daily fingersticks will certainly appeal to some, but my decision pivots on the accuracy as measured by the MARD number as being comparable. I will not give up 9-month transmitters and at least 14-day sensors for marginal performance benefits. Even with insurance coverage I would be paying more in copays.

I’m hoping the G4 line continues for awhile. It might only be available until the last Animas G4 Vibe drops from warranty.


@Terry4 my daughter’s supplier told us a few months ago that we would be required to upgrade to G5 in order to purchase a new system. She’s been out of warranty for a year.

Unless I’m misreafing, Dexcom plans for all users of stand-alone systems to upgrade to G6.

"Current customers who are out of warranty should continue to reorder their current Dexcom CGM System supplies. Current customers who order after March 27th will automatically be enrolled in the Dexcom G6 Upgrade Program and will receive Dexcom G6 after 90 days.

Current customers who are in-warranty past early June will be upgraded to Dexcom G6 when their system components reach out of warranty status."

I wonder if that is a supplier policy or Dexcom policy. Maybe the supplier has decided that they don’t want to stock the older G4 line. I just received a new G4 kit in early February 2018 from third-party supplier, Solara.


Heck, with Xdrip+ and my G5, I haven’t done a calibration in almost a week.

But, for the G6, I can fully understand the liability standpoint when you are talking about using this with a looping system. If you can say 10 days without a doubt, that isn’t that bad!
Cause as soon as someone could restart the sensor, three or four weeks in, someone looping could get into BIG trouble if something happened while sleeping, etc.

And let’s face it, they haven’t killed off the G4, and the G5 has been out for sometime. I doubt they are going to kill off the older systems that fast when they have already done all the work, development, etc.

I like the UI of the Dexcom apps a little better, but as soon as that transmitter battery warning comes up, it’s xDrip for me too. Another reason I hope we’re not going to be forced to upgrade to G6: having to wait for Johan (blessed be he!) to develop an upgrade.

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Since the G4 shares the same sensor with the G5, G4 sensors will be available as long as Dexcom supports the G5. The G4 battery can successfully be replaced at various non-approved places. That leaves the G4 receiver which can last for several years.

One other factor that will play in any Dexcom decision to withdraw the G4 from the market: there’s a Tandem pump that uses the G4, so Dexcom will likely support that pump at least until the warranty period expires.

I also prefer the G4’s range over the G5’s and the G4’s fewer data dropouts.


Me too.

Just ordered new G4 transmitter, and supplier sent me 2 G5s. Called them and they said it was a mistake, and they shipped the G4.

But at first I thought maybe the supplier had already made decision to stop supplying G4. It was an odd coincidence.

I have saved old dead G4 transmitters and would replace batteries if that’s what it comes to, as long as the sensors are still available.

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Yeah, I have three battery-dead G4 transmitters, candidates for a battery replacement, if needed. One thing that could change my personal position on the G6 is if someone figures a workaround tactic and can extend the sensor beyond 10 days without a loss of accuracy.

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Since my current G5 sensors only last me ~10-12 days anyway, with day 1 being oftentimes useless, I’ll be perfectly happy if they can get a dependable 10 day sensor. It’s been reported that the new sensor will perform better on day 1… that would be great.


I think the G6 will have trouble competing with Abbott Libre despite the obvious tradeoffs associated with the less expensive Libre. The longer sensor life for the G5 was one of several advantages often mentioned by those choosing Dexcom over the Libre, one of several factors making the G5 worth the extra expense. Now they are both “factory calibrated”, insertion process is similar and both have a 10 day sensor life. It seems to me that Dexcom will eventually need to lower their sensor price to stay competitive obtaining new customers.

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I wonder about the calibration. Just because it doesn’t require calibration, doesn’t mean it won’t need calibration. Right now, even though I have excellent coverage for my sensors, I still like to run them until they quit. Habit from the self pay days. I don’t like the idea of a hard shut down.

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IMHO, they will have an even harder time once the Senseonics CGM is certified by the FDA.

I think Libre’s no-calibration sensor influenced decision makers at Dexcom. Yet I think that Dexcom is reluctant to go head to head with Abbott on price. There’s also a group of loyal long-time Dexcom users, including me, who are not persuaded to make the jump to the G6. It’ll be interesting to see what price Dexcom sets with the G6. I think they’ll try to price three G6 sensors (one box) at the same or comparable price as four G4/G5 sensors, also one box.

That would make the G6 sensor more expensive than the G4/G5 and a lot more expensive than the Libre. Both sensors are comparably accurate with the Libre’s MARD at 9.7% and the G6 at 9%. (For MARD, lower is better.) The G6, however, can drop its MARD to the 7% range with daily calibrations. Dexcom’s product does maintain an advantage over the Libre with its ability to push alarms to the user.

Europe, with little insurance coverage for CGM or flash monitors, has already shown that the market decidedly favors the less expensive Libre. The US market is skewed with significant insurance coverage and this may push Dexcom to a higher price. This should be interesting and may prove daunting for Dexcom’s marketing. We shall see.