Starting with the Dexcom G4 released in 2012, I have bolused insulin based on my CGM. Although the G4 was not FDA-approved for insulin dosing, I was comfortable doing so “sometimes, in certain circumstances, and within certain guidelines.” That quote comes from a 2013 blogpost titled “To Dose or Not to Dose” and explains that I mostly trusted the Dex but averaged 8 fingersticks per day.
Fast forward 5 years. I regularly dose insulin off my Dexcom CGM and only average 4 meter tests per day. That average reflects sensor day 1 where I might test 8 times and other days where I may only test 2-3 times. The Dexcom G5 is somewhat more accurate than the algorithm of the original G4, but the difference is only a couple MARD points and not a huge statistical variation.
So what has changed that I have eliminated at least 4 meter tests per day?
What has changed is Me.
I have 10 years of CGM usage under my belt. The early years of Medtronic SofSensors were rocky with a huge improvement when I moved to the Dexcom 7+. The 7+ was reliable for trends but I don’t remember trusting it enough to guide my bolusing decisions. With the mostly reliable G4 numbers, I frankly just became lazy about using my BG meter. I had good insurance with no need to ration test strips and no issue poking holes in my fingers. I was just lazy and welcomed a small reprieve from a few daily diabetes tasks. Before I knew it, the laziness turned into a habit. It was initially a guilty habit but over time CGM reliance became entrenched in my diabetes decision-making.
And guess what. It didn’t kill me! And now it is FDA-approved.
Lately I have been frustrated with inconsistencies between my meter and my Dexcom numbers. It drives me crazy. I have always had issues with Dex sensors reading low. As I increasingly target normal-ish BG numbers, the Dex low tendency often results in alarms for lows that aren’t lows. Dexcom screams 65; meter says 85. Maybe I calibrate and Dex goes up to 75 before dropping back down to the 60’s. I know that numbers showing up after calibrations are determined by “The Algorithm” but sometimes if I enter 85, I just want the receiver to say 85.
My perfecto personality overreacts to diabetes numbers. When my meter and CGM feud, I calibrate too often. I over-manage blood sugars. I get lows and highs as I target perfection and my mental health meter explodes.
What do I do?
Do I start testing 8-12 times a day like in the old days? Do I donate the CGM to Goodwill?
Heck No!
I just move to Planet Dexcom and go with the flow of CGM numbers. I test less.
Although Dr. Bernstein might disagree, I believe that when you are 66 years old with 42 years of diabetes under your belt, 20 or 30 points here and there probably doesn’t matter a lot. Especially if I have a flatter CGM tracing because of fewer peaks and valleys. By not obsessively using my meter, I might miss some large Dexcom/meter discrepancies. At the same time, it hasn’t killed me yet. I am mostly hypo unaware. But because I have had so few catastrophic lows since the introduction of Dexcom G4, I have some confidence that if I pay attention to my body and my diabetes devices, I am somewhat protected from incapacitating lows.
Remember. It hasn’t killed me yet.
Note: Because I am on Medicare, I am using the Dexcom G5 and it will be a while before I have access to the G6. I find it interesting that many of the early-users of the G6 which requires no calibration are celebrating its accuracy. Simultaneously they are claiming that they are not using their BG meter. So actually they don’t know how accurate it is. They are living on Planet Dexcom and finding that it is a relatively safe and happy place to be.
There will come a day when blood glucose meters go away and everyone with diabetes uses some type of continuous glucose meter. We’ll live on
Planet Dexcom or
Planet Libre or
Planet Medtronic or
Planet Eversense or
Some other CGM planet in the diabetes universe.
Relatively safe and happy.
Test Guess and Go 
Planet Dexcom is a great way to describe it! It also reminds me of the B-52’s song Planet Claire : )
When everything’s a little bit +\- and guess-ish anyway, we sort of just have to choose a planet, hope for the best, and stick with it.
I think lately my kids might only prick 1-2 times a day and we don’t have G6 yet. I try to not hover. But when I DO hover (or check them in their sleep) Planet Dexcom is usually within a few points. Reassuring to read your post.
“When everything’s a little bit +\- and guess-ish anyway.” That’s diabetes in a nutshell, Katy. Thanks as always for reading. 😀
An excellent synopsis about our wonderful experience with CGMs. Laddie, you and I have almost the same time frames of our T1D experience. I was diagnosed T1D 51 years ago, been wearing pumps for 26+ years and CGMs also for 10 years (I started with the Navigator).
My migration away from 8-14 BG tests per day finally kicked in about 4 years ago. I just got tired of the finger sticks and decided to trust my Dexcom. I’m certainly not any worse for the wear and have a lot of faith in my G5.
My next hurdle is seeing what speed-bumps I’ll have to move from my Animas Ping to a tSlim X2 when support stops in September-2019. I’m sure it will be an adventure.
Good luck on your pump transition. Medicare doesn’t make hardware and supplies easy to get. I think they figure that we’re retired and need something to fill our time….
Many things to think about…long time animas vibe and dexcom wearer and last week’s endo appt says I am being too strict…causing anxiety…license to eat a donut? Nah…5.7a1c is worth it…i am on the planet with you. Nice twist!Thanks
Thanks, Sandy. You do know that today is National Donut Day…. 🍩
I, too, am using Dexcom G5 under Medicare. It’s my first CGM and I’ve only had it for 3 months. For many years I had to pay cash for all my supplies and I’ve experimented with a lot of low-cost test strips. The worst was one that produced a number in the 280’s and an immediate retest gave me a “LO”. Those test strips were so inaccurate as to be worthless. The Contour Next strips that are supplied with my G5 are at the top of the heap. NIH tests done in 2015 gave them the best score with only one other test strip coming close, Freestyle LIte. (https://www.ncbi.nlm.nih.gov/pubmed/25260047). For the most part, in my very limited experience, the finger stick numbers are reasonable close to Dexcom numbers most of the time and I have been comfortable dosing by the Dexcom result.. One thing I’ve wondered about though is placement of the sensor. In advance of receiving my Dexcom I looked up insertion videos on youtube and the first 3 I found all showed insertion into the back of the upper arm. I’ve also read of people using their thigh. When I read through the Dexcom material it stated that the only approved insertion location was the upper abdomen. So far I have only used the upper abdomen.
I’m inclined to agree with you, it’s not going to kill you. A woman who managed two pregnancies in the 70’s with primitive tools (comparatively) and has no complications can not be undone by a Dexcom.
Side note: I think Sandy Brown’s endo and mine may have gone to an endocrinology conference and come home with new ideas. At my last appointment my endo, whom I’ve been seeing for over 10 years, suddenly said “you know, you can eat dessert now and then”. I’m shocked.
I think that Dexcom is OK with upper arm placements. They just haven’t had it approved by the FDA and thus have to recommend abdomen. I prefer my belly for pump sites and also get adhesive allergies to Dex on my belly but not on my arms. Thanks for reading and commenting.
I primarily use side arms and side thighs for my CGM placement due to abdominal scar tissue. Even though these sites aren’t FDA approved, they’re by my Endocrinologist and my consistent numbers!
Medtronic recently had arm sites approved for its CGM and there is no reason to think that arms are not similarly successful for Dexcom users. I don’t use my thighs very often but I know lots of people have good results with those areas just as you do.
Interesting… this is pretty much my experience too. When the sensor is in, I’m checking 2-4 times per day now. When I do, the numbers on the Dexcom are usually within ten points of my meter after day one.
I have erratic results in the first 24-36 hours and that is one reason that I wear the sensors longer than 1 week. I used to go 3 weeks prior to Medicare when I was hoarding sensors. Now I go about 10-14 days which will fit with the G6 (if I ever get access to it!). Medicare is mostly fine, but don’t hurry to come join us, Stephen.
I have very accurate BGs from G5 when calibrating ever 12 hrs (fasting wakeup and pre-dinner that are typically less than 5 points difference. But the reality is its just a number! Going on 48 yrs T1D and have always had A1Cs 5.7-6.7. I also have been experimenting with long term (20+ days, 32 longest so far) G5 usage with similar matching numbers.
Im disappointed that the G6 can’t be re-started like I’ve been doing. I like less frequent installations and having backup inventory for the inevitable pharmacy/insurance screw ups!
The struggles a of T1D are real and endless, but remember, it’s just a number so focus on the trends instead 😊
Thanks, Trent.
I find many parallels with your experience, and dose most of the time off my G5, with only 2-3 tests per day these days. While I try to relax and remember it’s just a number (42 years of this…), that’s a LOT easier to do on the days when my pump sites are working and my BG numbers are responding to my usual patterns. Much harder when things seem to go a bit haywire for no discernible reason… 🙂 Thanks for your posts, I always enjoy them!
Thanks, Lucia. Yeah, life is tougher when things go haywire….
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I once had a well respected researcher explain the two parts of this issue. First, we have to remember that every single measure of glucose is really a range base don the measurement. instrument. No single measure is 100% accurate, instead they all operate within a range, even a blood draw at a lab is understood with in a range.
Second, the glucose in the interstitial fluid is likely a better measure of what our brain senses when it activates the endocrine system overall.
So is it bad that the blood in the capillaries in our finger shows a different blood glucose than our CGM?
I think no (my opinion). It is difficult but I have gradually learned to not put to much emphasis on the finger stick. Even if that is our traditional measure of glucose, it is a flawed measure just as the CGM is a flawed measure as well.
Those are some interesting points, Rick. I had never heard that institial fluid might match how I feel better than BG. Thanks as always for reading.
I can no longer leave comments about your Tandem reviews, but I wanted to thank you for the suggestion of the charger for the pump. We have struggled with getting the pump plugged in regularly and this suggestion is a great fix! Many thanks.
Thanks for your comment, Lisa, and I’m so glad that the portable charger is working for you. That is still the way I charge my pump almost every time.
Hi Laddie- I got a note from Senator Elizabeth Warren’s office today, as I had asked her to contact CMS about Medicare not allowing use of IPhone. The use of Iphhone is now approved and it will be rolled out by suppliers soon. I use Tandem T-Slim X2 and Dexcom G5, so this is great news so that I can keep my husband in the loop on his phone. Contacting Senator sometimes works! https://www.cms.gov/Center/Provider-Type/Durable-Medical-Equipment-DME-Center.html
Thanks, Patrice, for your advocacy. And yes, it is great that soon we will be using our smartphones and allowed to follow or be followed by our loved ones.