CGM useful or not?

[The Gadget Man]

New to the forum so excuse me if I am going over old ground here. I have been a type 1 diabetic for over 50 years so have used everything from urine in a test tube with a tablet to CGM's. I have only used two different CGM's Libre and my present favorite Dexcom One +.

My question is have we actually moved on at all. My original way of testing changed the urine colour so that you could compare it to a colour sheet that would give you the approximate blood sugar level. Systems improved until we got blood glucose meters. I used many different kinds and all worked well and except for the finger pricks were good. Then we got CGM's in some respects the holly grail. I started with the original Libre and ended with the Libre 2+. I became doubtful about the actual usefulness of CGM's when I was changed to the 2+. I had a number about 30% that was faulty in one way or another. I asked my diabetic nurse if there were any alternatives she prescribed the Dexcom One +. As an experiment I ran both together for a month. What I found was that neither gave the same reading at any time and neither was ever close to blood tests. One would read high and one low. To make this worse this was not consistent this would change for no apparent reason.
Then there are the known problems, pressure false readings and dawn miss readings.

My conclusion is that at best CGM's give an indication to your glucose levels, but then I had this 50 plus years ago with urine tests

 

[EllieM]

Hi @The Gadget Man and welcome to the forums. Like you I've lived through urine in a test tube, glucometers and cgms. I found a glucometer pretty life changing (it coincided with the introduction of MDI for me) but cgms (libre 1) allowed me to attain a much lower hba1c, though whenever it went much lower than 50 or 7% I lost hypo awareness and had ambulance inducing hypos.

I've had a pump for the last 2 years which hasn't improved my hba1c as much as I'd like but has removed the incidence and fear of severe hypos.

My two pregnancies were pre-cgm and frankly terrifying for family members and (to a lesser extent) me. I pretty well needed a full time minder when alone with my toddler during the second pregnancy. I would probably have gone for a third pregnancy had cgms been available then.

Are cgms accurate? Yes and no. I have sufficient experience to be well aware of when they may be inaccurate, and the pump cgm loop ensures that I never have severe hypos. I use my glucometer when I'm either very low or unexpectedly high.

Be aware that the dexcom G7 allows you to calibrate your readings if a sensor is "off", but I've only very rarely needed to use this.

The only downside of the new tech as far as I can see is that it can make people obsessive about their levels and lead to burn out. In the days of the test tube I just didn't care. (Admittedly I was a child then and my parents refrained from telliing me diabetic complication horror stories.) And of course you have to carry around more gear, specially when travelling.

 

[Ushthetaff]

I too came from the “ chemistry set” in the house era to measure urine sugar well it wasn’t measure per se it was either positive orange or negative blue . Seeing as this had no relation to actual blood sugar it was not the best control medium. The CGM has never professed to be as accurate as a blood sugar as it doesn’t measure blood.Used in conjunction with a blood sugar measure I have managed to bring my Hb1ac down from 100s to low 50s which will do for me

 

[Tony337]

Hi @The Gadget Man
Welcome...
Type 1 51 years MDI last hba1c 39 or 5.7.
You say yourself the CGM gives an indication and you are right and i find mine does what i need it to do for me.
I can get mine to read the same as finger prick but only with no fast acting insulin on board and no carbs.
It gets confused after a hard day at work and i have masses of carbs and novorapid on board.
We already know it is 20 minutes behind.
The first thing i did when i got mine was to take it for long walks to see what walking does for my levels.
So i factor in what i know and i end up with good levels.

The other thing not mentioned is the alarms.
When we were children the idea of a CGM was sci-fi whereas now (i work in a school) mum and dad can be at work and can access their childs CGM on their own phones. Marvellous i say and also don't forget we get the sensors on the NHS.

Whilst i take your point on accuracy i have got mine to work for me.

I wish you well

Tony

 

[The Gadget Man]

Thanks all for your replies. I was being a bit tongue in cheek with my post. I would not seriously go back to the days of urine testing. Haven't tried it yet but I am reasonably confident that I could keep my hba1c, more importantly my time in range, where it is by doing blood tests before meals as I use to.

Side point on recent visit to my diabetic nurse she indicated that time in range was more important than hba1c. This makes sense to me as logic tells me that hba1c, which is an average of your blood sugar levels, in theory could be good without ever having a single in range point. Very simplified I know but if your readings were equally 10.1 and 3.8 then your hba1c would be 6.95. So hba1c, if you relied solely on it could be yet another red herring.

Maybe the point I am making is that a diabetic has to take all this information that is available with a pinch of salt and just go with your gut felling.