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?
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.