On a somewhat related note, I have been thinking about returning to an insulin pump after many years MDI. I stopped using Medtronic because I developed an allergy to the adhesive and I was using too much insulin to last three days. I had to change sites every two days due to pain at the site. Now that I have cut back dramatically on my insulin use, I am interested in trying a closed loop system with Dexcom. I would be interested in knowing what my options are and if anyone has had better luck with adhesives other than Medtronic. I have not developed an allergy to the Dexcom adhesive. I also think I would do better with a pump I can wear on my arm which is not really possible with tubing like Medtronic has. I appreciate all input.
Thanks for this. Of course I’d rather have fewer sensor changes, all else being equal. The footnotes are important, though, particularly this:
“A study was conducted to assess the sensor life where 73.9% of sensors lasted the full 15 days. When using the product per package labeling, approximately 26% of sensors may not last for the full 15 days.”
I don’t know what percentage of current sensors fail, so I can’t make the comparison, but these numbers are worth bearing in mind when complaining about failed sensors. I share the annoyance when that happens (and I’ve voiced it here a lot). But manufacturers and regulators may have different notions of what “acceptable” failure rates look like than we do.
Overall the G7 has been much more reliable for me than the G6. I did find I had to switch to the back of the upper arm from my preferred thigh position but the sensors are much more reliable there. I also learned that 90% of the time I get a “failed sensor” issue at startup, it works for the full duration (currently 10 days) if I just restart it. The G7 sensors still have issues at times but the good far outweighs the bad in my experience; the trend information is invaluable. I am skeptical about them lasting 15 days but excited at the prospect of fewer site changes.
Thanks for the post! Knew it had been applied for. Am concerned about the stats, seems they’re just re branding the G7 for a longer duration and hoping it takes! I’ve put it on my discussion list for my Endo in May, but Lord knows if he’ll have any better info than this. I wouldn’t mind having it for the longer duration if it actually works, but question the stats. We’ll see…,
For people on Medicare it may only be an advantage if they allow for an extra 25% of sensors to account for failures. Currently they allow only a 90 day supply to be ordered when you are down to a 10 day supply. There is no allowance for if you have to remove a sensor for an MRI, or if it falls off. So they would have to allow for that 25% failure rate, or not.
Mike
So I’m actually ok with the 25% or so that will fail after day 10 if they continue their policy of replacing sensors that fail early. After a year or so in guessing I could get a few months ahead on these new 15 day sensors. If I lost my insurance or there was some kind of shortage this would be some piece of mind.
I’ve had zero trouble getting replacements for sensors that fail on day 8 and 9 over the last year or two.
I also really hate the first 48 hours of a sensor because of erratic readings. I do TONS of fingersticks. The first overnight I’m awoken with low alerts from my phone and pump every hour or so even with a 12 hour presoak. I dramatically lower my carbs and stop working out. I think if this 48 hours was cut to twice a month instead of 3 times a month I would be a little less cranky.
This is deemed a significant change in the device’s intended use so Dexcom will have had to prove that the extended life of the sensor still meets specifications and demonstrates equivalent performance criteria compared to the predicate (original G7). What may be more difficult to discern is whether any design changes were necessary to support the 15 day use
@funk I think your comment and my concern address the same thing, ie a failure to achieve the 15-day time of about 26% of the sensors (my reading of the info…am I wrong?) seems very high!
A local (Seattle area) clinic was enrolling Type 1’s in a current “Dexcom G7 device trial”. I found out a little bit about it…wear 6 or 7 G7 sensors in different spots on your arms/body for 15 days, doing 9 fingersticks daily, visiting the clinic a few times. All while continuing with your own personal CGM if using one. The study was enrolling during March (a few weeks ago) but I was out of town on a trip so was too late to sign up.
My guess is they are trying to get a better MARD statistic for a variety of placements. I would think they have to improve the sensor quality somehow to improve on that sensor longevity after Day 10 and to make that MARD improvement but no inside info here, just a guess.
The MARD is the nightmare in the bottle. Here is @spdif 's comment on TUD:
@Jran1984T1 the problem with loop systems is the accuracy; the G7 sucks the first 24 hours or so then it’s really great. The new MARD numbers show that it drops back to the accuracy in the first three days after day 12.
So at present, for looping, use the 10 day G7; not the 15 day one, because accuracy is everything in a hybrid loop.
FWIW, I also saw in the announcement that a new Rx was required for the 15 day G7, patients would not be automatically rolled over from the 10 day sensor.
The G7 sensor is only cleared for use on the upper arm for adults. My endo told me FDA would not clear G7 for other anatomical locations as the clinical data did not support it. I agree with you - my experience is that the G7 is much more reliable than G6
In a June 2022 interview Dexcom CEO on G7 being expanded to 15 days.
I’ve read about a potential G7 Plus, where the life of the sensor would be extended from 10 days to 15 days. Is that something Dexcom is working on?
SAYER: It’s absolutely something we would work towards. We stopped at 10 days at this point in time because we want to maximize the patient experience. Meaning, we want to make sure these devices last their entire useful life, and patients are getting what they signed up for.
To get to 15 days — we have the tools to get there. For most adults, the sensors last 15 days now. But the question is, how do you define most? Is it 65%, or is it 70-80%? Whereas, we know the sensors last 10 days for almost everybody.
More:
The biggest issue for 10 days often is the adhesive, and what somebody puts the adhesive through in their own life, or just how their skin reacts to our adhesive. We do have adhesive programs. We have an adhesive we picked for G7 that became quite good. We are testing a couple of others to be more sticky for a 15-day product offering
And: We do have a 15-day program going on. We don’t have an electronics or battery problem going 15 days with G7. It’s really more of what the customer experience is going to look like, and are we giving them exactly what they asked for.
If an endo makes a statement like this it’s a warning sign that the are clueless about how a product is tested, the data submitted to the FDA and diabetes technology, run don’t walk and find another endo. The clinical testing used the arm to get that documented, and the data submitted only included arm placement. This does not limit placement of a Dexcom CGM anywhere else. The FDA does not “clear” medical products, the approve the clinical data and testing was sufficient to release a product.
Apologies in advance for being pedantic but the regulatory distinctions are important and in the case of the G7 sensor, may explain why performance is better in one location vs another.
Below is the link for the 510(k) Summary of Safety & Effectiveness for the G7 Sensor. It was “cleared” to market by FDA via the 510(k) process, which is typical for a Class II device. The 510(k) process is based on substantial equivalence with a legally marketed predicate device (eg the G6 sensor) that shares many of the technological characteristics with the subject device. Some, not all Class II devices require clinical data. Devices cleared to market via 510(k) are legally not “approved” by virtue of the submission type. Companies who advertise as such can get into hot water with FDA.
Class III devices are subject to Pre Market Approval (PMA) due to their higher risk (eg implants). They receive approval based on their own V&V, Clinical data etc and not based on a comparison with another legally marketed device. PMA devices take much longer to get approved and always require clinical data to gain approval. PMA devices can be advertised as “approved by FDA”.
I hope that distinction is clear for you.
If you read the SS&E for K213919, top of page 3, it states:
“Insert only in the arm or buttocks: Don’t wear it on other sites as it may not work as expected.”
Also the table on page 6:
“Anatomical Wear Location: Arm (age 2+ years) or upper buttocks (age 2-6 yrs)”
Note that the G6 sensor indications are different:
“Abdomen (age 2+ years) or upper buttocks (age 2-17 years)”
Yes it sure does, from both a legal and a regulatory perspective. That is why when you call Dexcom with a product complaint/failure, one of the first questions they ask you is which part of the body are you using the sensor on? I have never used a Dexcom sensor off label so I have always answered that question correctly. Not sure what would have happened had my answer been different.
I got to love the defensive response that misses the FACT that the sensor can be placed anywhere that it works; it is not voiding the “warranty” to wear it in another location if it performs as it should or as directed by the physician. Example…if you have injured arms, it is perfectly acceptable to wear it on another part of the body. If the arm is not giving you the expected performance of the product, a different location can be used. The 504(k) is clinical data used to submit the device for approval for selling the device, not the only way it can be used. This is stated in the guide for the device. The reason for recording the location when getting a call from Dexcom is to collect data, not to deny warranty.
The “Don’t wear it on other sites as it may not work as expected.” clearly indicates that there may be a difference in the way the product works if not used on the arm, not that it cannot be worn in another location.
I have worked in the industry, used CGMs for 20 plus years, used pumps for 34 years, and have 54 T1D years behind me. One more item of note about the location is that the Canada release of the G6 used the Tech Support data in the use of the G6 in the US, not new clinical data, to be able to state that it will perform as expected on the stomach and arm.
I have used the G6 followed by the G7 for a number of years. T1D for 47 yrs, tighter control than most according to my endo with A1Cs in the low 6’s. My stomach layers show the wear and skin effects of years of abdomen sensor & pump canola placement. So I gave the G7 placement on the arm a try. First one lasted 5 days before generating weird readings. Second one lasted 3 days.
I do resistance training a few days a week and the usual house/yard work on weekends. Decent muscle strength and necessary fat store around the abdomen. But I was never aware of bumping or pressing on a G7 when on the arm.
Since I had very few problems with any G6 not lasting the duration, my endo recommended going back to abdomen placement. His other patients using G7s had not had any problems. My G7s last the 10 days there.
My endo recommended keeping my Tslim pump on the same side of my body as the G7 to avoid connection issues due to the weaker radio chips in the G7, experienced by some of his patients.
I recently had yet another allergic reaction to an adhesive on my arms, so I have one on my abdomen right now. I was reassured to find that Dexcom Canada does say that it’s approved for abdomen placement in adults! But that the upper arm “results in optimal performance.” Where can I insert my Dexcom G7 sensor? | Dexcom