Considering switching from Freestyle Libre 2 to Dexcom G7

[lsrpm64]

My employer, and by extension my insurance provider, is now opening up coverage. I am a Type 2 insulin dependent and used to only be covered by the FreeStyle Libre 2 system, Not Dexcom

I have tried it now for almost 2 years and have been disappointed. Many inaccurate readings (and yes I do recognize the lag between interstitial readings and fingerstick readings)and more than a few False low alarms, along with countless signal loss alarms. so many I have turned that off to protect my sanity.

but after the recent change with employer and insurance I now qualify for the Dexcom system. I see no reason to start with the G6 as the G7 is available in my area. That is a no brainer. But I am concerned that I will be destined for disappointment. I would rather go back to all the time use of fingersticks than deal with the inaccurate numbers, the false low alarms, and the signal loss.

Is the G7 far better? More accurate? Less prone to false lows and signal loss? It is more expensive than the Libre 2 but I would consider it worth it IF it has dramatically less issues. Has anyone switched from Libre 2 to G7? Thoughts. Opinions, etc?

Will I like it, love it, or hate it?

 

[rebrascora]

@Proud to be erratic switched from Libre 2 to Dexcom One and is now self funding G7 I believe and loves it. I think @mikeyB also uses it.
Personally I love Libre2 and it works really well for me BUT you need to be aware of it's limitations and indeed the limitations of all CGM.

We have a thread regarding the limitations of Libre and other CGM which I will link below. It was composed by a member here as a result of many discussions between members sharing our experiences and is very comprehensive. For instance the big one to know is that false lows through the night are generally compression lows where you have rolled over onto the sensor arm and the sensor squeezes thee underlying tissue causing a change in the chemistry and it registering a false low which will recover after the pressure is removed. If you wake up on that side when the low alarm goes off, that is usually the tell tale indication that it will be a compression low. Gradually you learn to position it where that can't happen or learn not to sleep on that side.

I think many of us find the signal loss alarm more of an irritation than a use and I disabled it.from the start as I had heard others complain about it here. Oddly, the alarms tend to still come through beyond the signal loss distance, so I am not sure what benefit it is.

Anyway, here is the thread link I mentioned...

CGM limitations and precautions

Moderator Note: This helpful reply was copied from another thread as it details some of the commonly experienced limitations of continuous glucose sensors. My blood sugar has been in perfect range for days now, but although I haven't changed anything, I'm starting to get very short periods of...

forum.diabetes.org.uk

Good luck if you move to the G7. I know the G6 and Dexcom One can be worn on other parts of the body so it is easier to negate the compression low issue. I assume the G7 can also be worn elsewhere but hopefully the members who use it can clarify that.

 

[Docb]

A couple of things @lsrpm64...

First off welcome to the forum. i see you are posting from Canada. No problem with that but most of the forum are UK based and differences in medical protocols between UK and other countries can cause confusion if we are not careful.

I do not use any of the tech. As a non insulin dependent T2 I do not qualify to have it supplied by our system and it would lose out on cost benefit grounds if I thought about paying for it myself.

I spent most of my working life measuring stuff and trying to make sense of the measurements and I suggest you do not think about accuracy because you have no idea how accurate the various devices are. They might give different results but unless you check them against the same calibrated standard you have no idea which is most "accurate". The real question is which is most convenient to use whilst giving you data you can work with. Only you can work that out, depending on how your diabetes behaves and your own particular goals.

I'll add my usual caveat..... my thoughts are only valid with respect to T2. T1 is a whole different ball game.

 

[Inka]

@lsrpm64 I switched from Libre 2 to the G7 and the difference is incredible! The G7 is amazingly accurate. I hardly ever fingerprick now apart from when I need to (eg when driving). I know I can trust the number it’s telling me. It also has a fantastic range of alarms, which actually work properly because the sensor is so accurate.

The sensor itself is small and very low profile. Insertion is more ‘definite’ and painless. The G7 doesn’t need a transmitter as it’s built in to every sensor (unlike the G6). I use the suggested overpatch that comes with each sensor and it sticks perfectly for the 10 days with no peeling or lifting. You can calibrate it, if needed, which can be very useful.

I love my G7 and for me it’s much, much better than Libre 2 because of its superb accuracy.

 

[pistolpete]

You cant really compare the G7 to the Libre 2, the Libre 3 is a comparison to the G7 and thats more accurate than the G7 and smaller. Dexcom is ok but its slow, even the G7 is slow compared to the L2.

I understand the problems with the Libre but I had exact same problems with Dexcom.

In reality I can turn a potential hypo around in less than 5 minutes with Libre, with Dexcom unless you finger prick your pretty much blind for 5 minutes, I understand that suits some people though.

Dexcom does suffer with signal loss and compression lows and you cant just scan the sensor like you can with libre to reconnect, you have to wait for the sensor to reconnect.

The G6 sensor is massive, its like having a mouse stuck on your arm and the mechanism for attatching it is ridiculously big and in the UK but that huge thing needs to be dispossed of in a sharps bin. The G7 is far better, if you can go for the G7. You may find it works for you its just to slow for me (when I got one to work).

 

[Proud to be erratic]

Hello @lsrpm64,
I moved from Libre 2 to Dexcom One because I found L2 unreliable and not sufficiently close to actual BG. I had a 50% failure rate with L2. Dex One was a little better but still not terrific. I trialled Dexcom's G7 and found that so good that I continued to self fund the G7. Fortunately I now receive G7 through the NHS.

I am extremely happy with G7 and like @Inka I can now go for extended periods without any finger pricks. I had not realised how much extra stress I was experiencing, just because of needing to check that my L2 or Dex One CGM readings were realistically close to actual BG before taking any bolus dose.

Unlike @pistolpete I rarely experience either compression lows or signal loss with G7 and it is certainly not too slow for me. I particularly appreciate the wider range of alert settings available to me with G7. The L2 low alarm is capped at 5.6 mmol/L which was sometimes just too late in alerting me when my BG is rapidly falling; G7 allows me to have a low alert at 8.4 (which is in practice higher than my requirement) but I regularly use a low alert setting of 6.5 which gives me time to assess and decide if I need to take corrective action in a timely manner. Overall G7 is a winner for me; I prefer the L2 logbook features over G7's history recording - but that is a minor inconvenience in relation to G7's better reliability and the reassurance that comes from that.

 

[rebrascora]

The G7 is amazingly accurate. I hardly ever fingerprick now apart from when I need to (eg when driving). I know I can trust the number it’s telling me. I

I could say the same about the Libre 2. I bolus from it, i treat hypos or near hypos from it. I correct from it. I generally only need to do 2-3 finger pricks in the 2 weeks of sensor life. It sticks well and I have to prise it off at the end of 14 days. I trust it enough to have done 6 stacked corrections from it the other night, some of them just half an hour apart and it didn't let me down. I love my Libre 2 provided I take into consideration it's limitations and quirks, which I can very happily live with and some of which will apply to other CGM systems.

It seems that what works better is very much an individual thing.

 

[helli]

yes I do recognize the lag between interstitial readings and fingerstick readings

yes I do recognize the lag between interstitial readings and fingerstick readings

This comment suggests you do not understand the Libre algorithm.
Sure, there is a lag between interstitial fluid and BG changes. However, Libre understands this lag too and "predicts" the current value so you should not see the lag unless your BG trend changes direction in the last 10 minutes

Is Dexcom better than Libre? In my experience and reading the forum, I would say we are all different. People get very enthusiastic about Dexcom accuracy. I trialled it and was unimpressed...for me.
The only value over the native Libre app was that I could calibrate the readings against finger prick readings. But I found the app too basic.
But that is my experience. We are all different and, without trying it, you won't know if it is better FOR YOU.

 

[rebrascora]

Sure, there is a lag between interstitial fluid and BG changes. However, Libre understands this lag too and "predicts" the current value so you should not see the lag unless your BG trend changes direction in the last 10 minutes

Or when the rate of change changes. ie. It is reliable when levels are increasing or decreasing at a uniform rate, but if the rate of change slows, for instance when levels are rising quickly and then reaching the top of a peak, the extrapolation of the algorithm will overshoot until it gets more data showing that BG has levelled off and then it corrects itself and is why you might have an event marker hanging above or below the graph line.

 

[lsrpm64]

@Proud to be erratic switched from Libre 2 to Dexcom One and is now self funding G7 I believe and loves it. I think @mikeyB also uses it.
Personally I love Libre2 and it works really well for me BUT you need to be aware of it's limitations and indeed the limitations of all CGM.

We have a thread regarding the limitations of Libre and other CGM which I will link below. It was composed by a member here as a result of many discussions between members sharing our experiences and is very comprehensive. For instance the big one to know is that false lows through the night are generally compression lows where you have rolled over onto the sensor arm and the sensor squeezes thee underlying tissue causing a change in the chemistry and it registering a false low which will recover after the pressure is removed. If you wake up on that side when the low alarm goes off, that is usually the tell tale indication that it will be a compression low. Gradually you learn to position it where that can't happen or learn not to sleep on that side.

I think many of us find the signal loss alarm more of an irritation than a use and I disabled it.from the start as I had heard others complain about it here. Oddly, the alarms tend to still come through beyond the signal loss distance, so I am not sure what benefit it is.

Anyway, here is the thread link I mentioned...

CGM limitations and precautions

Moderator Note: This helpful reply was copied from another thread as it details some of the commonly experienced limitations of continuous glucose sensors. My blood sugar has been in perfect range for days now, but although I haven't changed anything, I'm starting to get very short periods of...

forum.diabetes.org.uk

Good luck if you move to the G7. I know the G6 and Dexcom One can be worn on other parts of the body so it is easier to negate the compression low issue. I assume the G7 can also be worn elsewhere but hopefully the members who use it can clarify that.

I am already aware of the possibility of compression lows and that is not what is happening to me. It has happened when sitting on my couch. And I have been more than careful of the placement in order to avoid compression lows.

I am wondering if I can put it on my belly. But I am afraid cause I am seriously overweight. And I am concerned that I will “rub it off”

 

[Proud to be erratic]

The device is approved for use when worn on the arm. That positioning particularly affects its approval and acceptance by the UK DVLA.

During the peak of COVID lockdown I was only driving a couple of times a week to the Hospital for my chemotherapy and because of its unreliability for me I was already getting fp readings lots of times daily, more than enough to satisfy DVLA requirements without CGM. So I wore my sensor on my chest, above my nipple, and that gave me better readings, which encouraged me to continue experimenting with different body positions. I found when on my chest my phone scans were quicker and didn't seem to need my phone to be in exactly "the right place" to get a reading first scan each time.

My experimenting drifted to a halt because I came across the Diabox app which converted L2 into a real time CGM on a so much better interface for my android phone. Diabox even displayed my continuous readings onto my sleeping phone - how impressive that was (how 3rd rate the Freestyle app for Libre 2 was instantly revealed!). No more scanning, no more waking up a phone and then waking up an app; just look at the screen for a reassurance check. Way superior alarms and alerts with much better sounds and much better graph displays (in landscape if you chose) (how restrictive the Freestyle app suddenly became; all fur and no knickers as an aunt would say!).

After 12 months I happily accepted an offer to try Dex One - gracefully accepting that my body and Libre were essentially incompatible. Improved reliability but with clumsy and less friendly tech and still inaccurate with (then) no calibration.

One of the benefits of CGM is getting a less stressful way of managing my D and its only now with G7 that I better appreciate that technology can take away some of that stress.

 

[Inka]

Or when the rate of change changes. ie. It is reliable when levels are increasing or decreasing at a uniform rate, but if the rate of change slows, for instance when levels are rising quickly and then reaching the top of a peak, the extrapolation of the algorithm will overshoot until it gets more data showing that BG has levelled off and then it corrects itself and is why you might have an event marker hanging above or below the graph line.

Yes, like everything it depends on the individual, but when my clinic told me about the accuracy of the G7 I was pretty cynical. I read up on the studies and thought I might as well try it. I didn’t think it would be as accurate as it’s turned out to be by a long stretch. My experience is reflected in my clinic. Nobody who’s trialled the G7 has gone back to the Libre.

Just as a note - I use the Dexcom G7 receiver not a phone. It’s tiny and I find the information on there more than sufficient. I also like the predictive alerts.

 

[rianos]

I switched to self funding the G7 after I found the L2 extremely inaccurate compared to a glucometre reading. I immediate found the G7 to be much more accurate - to the point that about 75% of the time it agrees exactly to my glucometre reading and the other times it's never more than 0.5mmol out. With the L2 I found it could be plus/minus 3.5 at any given stage which I found totally unacceptable. I also do not know why some people 'apologise' for the L2 and state to give it 48 hours etc - the G7 takes at most 30 minutes to warm up and is accurate right away for me.

I also detest the way the L2 corrects its graph and effectively does not give an accurate history of what it has told you your sugar is - for example it regularly told me I was high or low and then corrected itself and removed the high/low from the graph and quite frankly I am unsure why this is allowed - the G7 plots a graph and allows you to scroll back and see exactly what it said your sugar was at a given time - it doesn't try to lie and correct itself.

As others have mentioned the alarms are light years ahead of the L2 and even the L3 and the overall app and user experience is infinitely better - it interacts with apple health to show average/range of glucose etc, you can ask Siri 'whats my glucose' and it will reply - which I found extremely helpful when driving 900 miles to the South of France in the summer and also the app has a widget so you can see your glucose/graph directly open your Home Screen without having to enter the app which I also find a really nice touch.

The only things I would say I found better about the L2 was that it stuck better to my arm - by the end of the 10 days the G7 is starting to lift around the edges for me and also sometimes the G7 would lose signal at a relatively low distance away from my phone when the L2 wouldn't.

I recently did an experiment when I wore my G7 on one arm and the L2 on the other to compare results and found the L2 at any given time could read +/- 3.5 compared to the G7 however I noticed that this didn't last for long and the L2 would generally correct itself within about 30 minutes and generally arrive at a value within about +/- 1 of the G7 but the issue with trying to rely on the L2 would be if I checked it at one of the points it is wrong before it corrects itself. I never had an issue with the L2 before the update that made it a CGM and to me it seems like the transformation to a CGM updating glucose every minute was too much for the L2/algorithm and it simply isn't good enough and is inaccurately trying to predict my glucose. I think the 5 minute intervals of the G7 is more than enough - I would rather an accurate result every 5 minutes rather than an inaccurate guess every minute. I should counter this by saying that my mother uses the L2 and it always seems to agree very closely to her glucometre (which is the same type of glucometre I use) so perhaps each company's algorithm just works better for different people.

 

[Tdm]

Best thing to do is give it a try, see if it works better for you. For me the dex g6 is a big improvement on libre 2, but as people have said, different sensors suit different people