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My 1300 days on CGMs / FGMs
November 22, 2020 / Advocacy / Technology / Type 1

My 1300 days on CGMs / FGMs

25 min read

I will first resolve the doubts of all those suspects – have I regretted the money spent on all these 1300 days? NEVER!  Some spend it on cigarettes or other vices.  I decided to invest that money in my health!  Let’s face it – using CGMs (Continuous Glucose Monitoring System – in my case Dexcom) and FGMs (Flash Glucose Monitoring System – Freestyle Libre) is an extremely expensive sport and for many it is really difficult (actually impossible) to raise the necessary financial amount.  As my favorite Adam Brown writes in his book Bright Spots & Landmines, and I sign in full

However, in this text, I would much rather focus on my experience than on costs.  However, this will bring more benefits, and mentioning the costs only negative emotions, especially for fear of the decision that will follow us by the CHIF this Tuesday.

The difference between CGMs (hereinafter Dexcom, since I used it) and FGMs (hereinafter Libre) technology is that Dexcom offers the possibility of alarms, and Libre does not (although there is everything to do to get alarms, but in the original package they do not exist).

In the next few lines I will try to approximate the advantages and disadvantages of both systems.



In case we sleep deeply and we recalculated the amount of insulin, or we were extremely active that day or the anticyclone is strong (and we didn’t listen carefully to Vakula (a famous Croatian meterologist)) or we just have diabetes and there is no answer to why our sugar dropped sharply, Dexcom receiver will signal with a tone and vibration that we are in hypoglycemia and that we need to eat something.  We set the desired value of sugar at which we want the alarm to sound.  In this case, we will prevent the occurrence of hypoglycemia (and vice versa – hyperglycemia) and maintain its values ​​in the desired range.



Yes – alarms are sometimes annoying…And there is nothing more beautiful than sleeping through the night without a hypo or hyper alarm playing.  But, there are indeed situations when these alarms are extremely useful, so that the “lack” of waking up on time and preventing something much worse cannot be treated as a big flaw.



Dexcom and Libre:

The Dexcom sensor is slightly larger and a little more complicated to set up.  The application itself is a bit more painful than compared to the Libre sensor.  When installing the Libre sensor, I personally do not feel any pain, while with the Dexcom sensor, I still feel that something stung me.  Since the area affected by the patch with the Libre sensor is smaller, our skin also has more space to breathe and is more comfortable to wear.  The Dexcom sensor has a guaranteed shelf life of 7 days, but all users know that this period can be extended.  I had each Dexcom sensor on hand for a minimum of 4-5 weeks, with one even reaching the 8-week deadline once.  The Libre sensor, on the other hand, can be used for a maximum of 14 days and there is no possibility of “cheating”.  Of course, if we look at the cost, we would like to have the sensor in use for as long as possible, but if we look at the sweating factor and after a few weeks of using the sensor in the same place we get redness around the place of its application – then the possibility of changing more often seems more tempting.  Personally, I like Libre sensors a lot more because of the size, easier and painless application and the fact that I HAVE to change it after 14 days.  My skin will be more grateful for that, especially if I continuously wear and change the sensors one after the other – as it is the case with me.



Yes – the sensors are a bit more inaccurate than measuring glucose from a drop of blood (finger).  The reason is that the sensors measure the level of sugar in the intercellular fluid, and due to the anatomy of the body only after the carbohydrates from the food eaten are transferred to the blood, it is the turn of the intercellular fluid.  This means that the whole process is a bit slower and that the value of sugar obtained through the sensor will be later than that of the blood and will be a little more inaccurate.  However, the question is which is more important to us – to know exactly in mmol the value of glucose or is it more important for us to follow the upward / downward trend and know in which direction our sugar “travels”?  Whether my blood sugar is 5.0 or 5.9 is irrelevant to me, but the information from which I see that my sugar drops sharply or rises sharply is what COMPLETELY EXCLUDED from my life all those severe cases of hypoglycemia that I struggled with before using the sensor.


Comparing Dexcom and Libre – I haven’t noticed that one is more inaccurate than the other, but there are people for whom one of the devices is more accurate and the other totally inaccurate.


How to make the right decision – Dexcom or Libre, or CGMs or FGMs?

During the day I think it almost doesn’t matter if you have one or the other system because despite the fact that Libre doesn’t have sensors, you can scan and check your sugar at any time.  Of course, sometimes we forget that, so we are sorry that we still do not have alarms that will warn us in time that we need to react.  In case of special situations when it is extremely important for us to react in time and prevent possible jumps, either in hyper or hypo sense, I give preference to Dexcom because regardless of our concentration and forgetfulness, alarms are like tax administration – they will never forget you.  It will wake you up “without misery” in the most beautiful part of your sleep or remind you during the exam with a vibration that you still need to concentrate on your sugar for only 30 seconds in order to complete the exam in full concentration.  I consider alarms to be a big plus for pregnant women who do not have to wake up unnecessarily during the night and check their glucose levels, but the alarm will really do that if and only when it is needed.

On the other hand, Libre patches seem stronger to me than those with Dexcom sensors and there is less possibility of peeling off.  The fact that they are smaller is a big plus for me because I really feel that my skin is a bit more grateful than with the Dexcom sensor.  But what works best for you, you’ll only know if you try both systems.  Each has advantages and disadvantages, but both are worth their weight in gold.


The other day, it happened to me that during a more intense sports activity, I took my sensor off my hand.  The sensor flew away so perfectly as I watched helplessly.  Then for the first time in 1300 days I was only a few hours without a sensor.  I felt like a dumb hen.  Although I measured my BG (Blood Glucose) with a brace, the values ​​I got were nothing but the simplest number with which I have no insight into what is really happening – does my sugar rise under the action of adrenaline after training or does it fall sharply?  My BG at that time was 7 mmol / L.  In 90% of cases, the action of adrenaline always begins at that moment, and the fact that I was without an insulin pump for 2.5 hours additionally contributes to the BG jump.  That is why I gave myself the necessary correction, which in 90% of cases is appropriate and necessary.  But this time it fell into those rare 10% of cases and my BG suddenly started falling without my awareness of it.  After a full 3 years, I felt one of those stronger hypoglycemias that I used to struggle with every day, and my hands were taking on the symptoms of Parkinson’s disease and the shivering was my roommate for the next few minutes.

With the use of continuous glucose monitoring sensors, I COMPLETELY dropped such episodes, and I almost forgot about the real feeling of hypoglycemia.  Thanks to the sensors for continuous measurement, I manage to keep my body as close as possible to those in healthy people, and that is a wonderful feeling.  Then, I felt both physically and mentally well, and my productivity was at its maximum.  Of course – we all have our better and worse days, but like hypoglycemia, extremely high hyperglycemia has become almost a thing of the past for me.

Is there really an additional need to prove to the competent institutions that, as Adam Brown says, this SAVES LIVES?  YES – continuous glucose measurement really saves lives, and everything else is a crime!

The text was published in the magazine ZADI 01/2018.  It is a magazine of the Zagreb Diabetes Society, which I warmly recommend to all people with diabetes, as well as participation in educational workshops provided by their employees and volunteers!

Maja Vukovic Read more posts by this author
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