Disclaimer: none of the companies paid me to be mentioned here, in fact they all make a lot of money on me…
Type 1 diabetes means that I don’t have any insulin production. My blood glucose level is too high. The treatment is about measuring your blood glucose and “push” it in the right direction with the help of insulin, food or exercise. (Ok it’s far more complicated than that but I will save myself a lot of time and recommend Google). My blood glucose meter has such a mandatory place in my daily routine that it’s easy to forget that these machines haven’t been available for that long. The first ones for home use were launched in 1981 and they were nothing like the little white button on my arm, my FreeStyle Libre that continuously measures my blood glucose.
The history of the blood glucose meter started with Leland C. Clark Jr, who on the 15th of April 1956 presented his first paper about the oxygen electrode, later named the Clark electrode. In 1962 Clark and Ann Lyons developed the first glucose enzyme electrode based on his early inventions. It was a biosensor based on a thin layer of glucose oxidase on an oxygen electrode. The readout was the amount of oxygen consumed by glucose oxidase during the enzymatic reaction with the substrate glucose. The first devices were only available in hospitals and were big heavy machines that, in due time, showed the result with moving needles on a display. Studies done in the late 1970s demonstrated that home monitoring did indeed improve glycemic control in type 1 diabetics, which paved the way for the first over the counter devices around 1981.
In some regions, especially North America, the availability of home test devices were delayed as hospitals resisted. They argued the superior accuracy of the lab measurements outweighed the advantage of the instant result for the diabetic at home. Some officials still resist today, though the cost of complications due to poor glucose control greatly outweighs the costs of test stripes, lancets and so on.
The blood glucose meters improved over the years; the size reduced, the measurement time went from a couple of minutes to a couple of seconds, and the amount of blood needed decreased. You could use other parts of your body instead of your fingertips, like your arms, and the general handling became easier.
Still, even with all this development, the blood glucose meter has one major problem. All these measurements gives you a set of individual data points. In-between those is a vast land of uncharted space. You might go to bed with an ok value and wake up, sky-high, wondering what happened;
“Did I have a hypoglycemic attack that I didn’t wake up from and then a recoil? Did I sleepwalk and raid the kitchen? Is it the dawn phenomenon, do I need more base insulin to counter that? Or less insulin if I’m having hypos during the night?”
If you want more data to evaluate and optimize your insulin dosage, you’ll have to set your alarm and measure your blood glucose several times during the night. Diabetics need their undisturbed sleep just as much as healthy people. If it’s only about your own health, you might decide that sleep takes priority over more data. If it’s about your child however it’s a different story. A lot of parents with diabetic children check their child’s blood glucose every night. There are parents that haven’t had a full night sleep since their child got diabetes, which might have been 10 years ago…
The introduction of continues glucose meters, CGM was a total revolution for the diabetics. Instead of checking your blood glucose with a machine, you have a sensor semi-permanently inserted under your skin. You have your blood glucose on a display and, here’s the magic; a curve over your blood glucose level during the last hours. If that mysterious high value in the morning was due to an unknown hypoglycemic attack, you can see that your blood glucose dropped to a very low and after that spiked, because your liver emptied its storage of glycogen in order to save your life. If on the other hand that high number was a result of the “dawn phenomenon” then your blood glucose level was probably fine for most of the night and started climbing during the early morning.
The dawn phenomenon is a surge of hormones that the body produces daily around 4:00 to 5:00. It’s a sort of “kick-start” that you need, something all people have, but since a diabetic doesn’t have the normal insulin regulation, the blood glucose climbs during to morning.
The point which I’m getting to; both a hypoglycemic attack during the night and the dawn phenomena gives a high blood glucose in the morning. It is key to know which type of problem it is, as it requires completely different types of changes in your insulin dosage. If you only have the two separate data points, 22:00 and 07:00, then you can’t tell which of the two problems it is. See how wonderful it is, when you have much more data about your past to base your future actions on?
That was one of the huge benefits of a continuous system. The other one is that I don’t just get a number on that display, there’s an arrow next to it. Since the system has so much data about my blood glucose level during the last hours, it can make a prediction on how it will behave and displays an arrow, showing how your blood glucose will move for the upcoming hours. Even if you don’t know that much about diabetes, you understand this simple visualization. Like last Monday, when I was taking meeting minutes for one of those “marathon meetings”. I was checking my display for my continuous blood glucose meter, about once every 15 minutes, and noticed that although the blood glucose is perfect now, it is going down. So, a 5 minute break, eat some sugar, and continue to work. If I only had a standard blood glucose meter, then I would have gotten a hypoglycemic attack and I would have needed a 30 minute break. Not the mention that taking a test in your fingertip, while typing on your computer is somewhat difficult.
There are two types of continuous glucose measuring systems, CGM and FGM. Continuous Glucose Measurement systems are provided in Sweden mainly by Dexcom and Medtronic. They have alarm features, a signal if your blood glucose drops too low. This is extremely helpful, for those diabetics that have unawareness problems, where you don’t sense yourself that your blood glucose is too low or for children who not yet can communicate this with their parents. The display that sends the alarm can lie in the parents’ bedroom, waking them up if their child gets hypoglycemic during the night. Mum and Dad can get their much-needed sleep now.
The fear that your blood glucose will drop during the night, without you knowing, making you unconscious, and resulting in you never waking up again, is (realistically or not) one of the diabetic’s worst fears.
The CGM has one big problem; it is, not surprisingly a very expensive system. It’s usually only prescribed to children (with very actively insisting parents) and to adults with severe unawareness problems.
The introduction of FreeStyle Libre in 2013 changed the game. It’s a flash glucose meter, FGM. While the sensor in the CGM measures and stores the data for a long time, usually about 90 days, the memory in the Libre sensor only holds eight hours of data. This means that if you don’t scan the sensor with your hand device, i.e. retrieves the data at least every eight hours, you get an incomplete data set. If you don’t scan the sensor last thing before bedtime and first thing in the morning (or sleep in) you don’t get the full story of your night problems. Also the FGM system doesn’t have any alarm functions.
An inferior system to the CGM. Thus a less expensive system. This is continuous blood glucose meters für alle…
This is why the Libre has changed the game for so many diabetics; since it costs much less than a CGM system, the counties in Sweden are prescribing this system in a high rate to the diabetics, making their lives far more manageable and having a drastic impact on the average blood glucose levels. … In fact, the Libre doesn’t cost more than that you can actually buy it yourself (provided that you have a reasonable well paid job) and it is partially marketed as such. It will be very interesting to see the statistics when the Libre have been in wide-spread use for about five years.
There is one big nemesis with the Libre, a problem that also occurs with the other CGM systems and more or less with any medical device attached to your body: your skin rarely appreciates having something glued on to it for a long time. Particularly with the Libre, which is attached to your body for 14 days, it is a huge problem that so many people get skin reactions to the adhesive. A great deal of us continue use it anyway, as the benefits are still that good.
The solution is on its way though.
The Sensonic Eversense is based on a sensor inserted subcutaneously in my upper arm, with a transmitter above, and measures my blood glucose around the clock. The sensor has to be inserted by help of medical staff, unlike the Dexcom and Libre which the diabetic changes herself. The sensor stays there for 90 days, and doesn’t use the Clark electrode principle. Instead the sensor is coated with a light sensitive biopolymer, the transmitter shines a light on the sensor and calculates the blood glucose levels based on the reflected light.
You remove the transmitter every day, and clean your skin, which greatly reduces the risk of skin reactions to the adhesive. (You have to take it off, as it needs to be charged every day and it is not waterproof.) It has all the alarm functions that you might desire and instead of a “stupid clumsy hand device” it sends the data to your smartphone via Bluetooth.
This is the “crème de la crème”. Though, I’m not going to sugarcoat it, the cream needs a little more processing in the dairy, as there are some issues. But it has great potentials. It’s expensive, obviously, but it is quite possible that it can work longer than the specified 90 days. When I daydream about future technology, this thing lasts for a couple of years. One of those in every diabetic, type 1, 2 and everything in-between and then as they say, Bob’s your uncle.
And now you have an abundance of data, every second of your day. Truly an amazing future…
Having type 1 diabetes means being stalked by data, and with these new inventions there’s no escaping. 24/7 you have your current blood glucose value hanging over you, demanding being taken into consideration. It is a mandatory part of daily life; you study your CGM curve, consider future plans and make a prediction on how much insulin you will need. Underneath the surface, always in the back of your mind, are the short and long term side effects of the disease; eyes, kidneys, nerves and feet. Don’t go all hyperglycemic so that you fry your blood vessels and nerves, don’t go all hypoglycemic so that you become unconscious, and potentially exiting this world. That number is always chasing you, like a grade on your performance, because the numbers are rarely within the by healthcare demanded range.
That’s the issue here; I am my own treating doctor. I make all the decisions about my treatment, thus every time it fails it’s my own fault. If I get problems with my eyes due to high blood glucose levels then I deserve it, right? With the home blood glucose meter all responsibility landed on the patient itself. And that dark cloud of guilt, inadequacy and fear can be huge sometimes.