What on earth are you on about?
In the unlikely event that you have never heard of the Libre, or Flash monitoring, here's a brief overview: It's not quite a CGM. It's not quite a Blood Glucose monitor.
Too brief? Oh, OK... here's a bit more detail: The Abbott Freestyle Libre is a new kind of blood glucose monitoring technology that sits somewhere between existing CGM options and traditional SMBG (fingerstick) monitors. It measures interstitial glucose levels using what Matt (Abbott's techical bod) described as 'wired enzyme technology' and Fiona (communications lead) referred to as 'special sauce'. If you've not looked into CGM before, interstitial glucose is not quite the same as blood glucose. It is measured in the fluid that surrounds the cells in tissue rather than from the blood itself. Typically these levels lag slightly behind BG by up to 10-15 minutes, but Abbott are using an algorithm to adjust readings which they claim reduces this lag to 5 minutes or less on the Libre. The measurement is performed with a tiny, flexible filament inserted under the skin and attached to a small, flat, circular sensor, roughly the size of a £2 coin. Abbott recommends that the sensor is worn on the back of the upper arm which seems to give optimum results and is less likely to be knocked off by doorframes. If you are writing a blog post, you will also notice that this location is virtually un-photographable one-handed - see below. The Libre's sensor measures glucose levels once every minute and stores 8 hour's worth of data. One of the main differences between the Libre and traditional CGM is that the data are not sent via transmitter/receiver continually. To access the information you simply wave the reader (or is it 'flash'? or perhaps 'swipe'?) over the sensor and you will be given a glucose concentration reading taken at that moment along with a graph of data from the previous 8 hours. Data points on the graph are created every 15 minutes averaged from the readings taken at 1 minute intervals. You also get the 'trend arrows' which will be familiar to CGM users and give an indication of which direction, and how fast glucose concentrations are changing. The near-field communication works anywhere between 1cm and 4cm and will happily ready through clothing, even as much as a skiing jacket they said. I've already smiled to myself as I walked down a street and checked my levels by swiping my reader over the arm over my coat.
I was hugely impressed with how easy it was to insert the sensor. It was also absolutely painless, significantly less 'stabby' than a set insertion for Artoo. Everyone around the table inserted their sensors at the same time, and noone seemed to feel a thing. The sensor came in two parts that needed to be pushed together which seemed to 'prime' the self-serter. Then you chose the back-of-arm location you fancied and applied gentle pressure to the composite gizmo which gave a reassuring click. Interestingly Abbott mentioned that an awful lot of care, attention and engineering boffinry had gone into the seemingly simple process. Including the 'click' which happens only as the inserting spring/needle withdraws. As a result you don't tense up on insertion, because by the time you hear the click - it's all over. Dave (@sowerbee) did ask whether much of the resulting plastic was recyclable, but it seems that almost none of it is - to keep the process as simple, reliable and precise as possible the idea of a reusable inserter seems to have been dropped quite early on. Long term Libre users will probably also need to get a bigger sharps bin - much like the self-serting Mio sets for the Veo, most of the plastic leftovers need to head for incineration. Once you have inserted the sensor the handset begins a 60 minute countdown before the first reading is available. The sensors are being described by Abbott as 'factory calibrated'. While traditional CGM sensors have required occasional BG/fingerstick calibration throughout their life, Libre sensors are manufactured in such a way that this is not necessary. I did ask what would happen if you had forked out your own hard-earned for a sensor only to find that it was stubbornly and continually miles out from your BG monitor and it was suggested that this would be a 'contact customer services' moment. I got the impression that if you could demonstrate that a sensor was massively misbehaving through no fault of your own they may well send a replacement.
Sensor life is 14 days.
From what I can tell there is no way to extend or restart sensors. Each is electronically paired to the handset and begins to count down 14 days from the initial 60 minute 'Start New Sensor' countdown. Smart cookie Chris (@grumpy_pumper) asked what might happen if your reader developed a fault at some inconvenient time - say 5.45pm on the Thursday before Easter. It would be days before a replacement receiver could be sent, so even if the new reader could be paired with the old sensor (and thinking about it now, I'm not even sure it could) several days of 'sensor life' would be lost. Without promising anything concrete, again Abbott seemed to suggest that they would try to behave fairly. Certainly in a market where they must anticipate a significant number of customers will be self-funding they are aware of the need to be seen to be fair if any problems occur. Abbott's research data suggest that sensor accuracy is likely to be slightly further out from BG meter readings during the first 24 hours after insertion, and then more accurate through days 2-14. Early days for me, but this certainly seems to have been my pattern with the first sensor. It is remaining very comfortable after the first few days. I'm currently on day 3 and on the whole I would not know it was there. If I had my insertion time again I might attempt to make sure it was just higher up my arm than my t-shirt sleeve line, but the sensor is very discreet and if anything just looks like a nicotine patch to everyone else so it's not particularly problematic if it is on show. It certainly doesn't scream 'medical device'.
The reader looks very like a normal BG monitor. It has a single button and then uses a decently responsive touch screen to navigate between various functions, displays and data handling options. Nice clear colour screen too. It was really easy and straightforward to set up and is very intuitive to use. No real need to go digging around in the handbook so far. The reader stores 90 days of data, and provided that you swipe your arm at least 3 times a day at the right moments you get a full 24 hour picture of changes in glucose levels. So far I have been swiping with such frantic, gleeful regularity that I can't actually tell you what happens to graphs where you've run over the 8 hour sensor storage limit, but I suspect you would just see a gap. Along with the 8-hour graph that you can see each time you swipe you can also dig back through a logbook of recent swipes, which you may have tagged with references to insulin, food, medication, exercise etc or view daily graphs 24-hours to a screen or check a variety of analytical screens.
The handset will also function as both a standard blood glucose monitor or blood ketone monitor (using the appropriate Freestyle Optium strips). Somewhat inevitably, the Abbott bumpf suggests that you check your BG level with a fingerstick meter if your levels are changing rapidly (where the potential difference due to lag between interstitial readings and blood glucose readings could be more marked) or if the result on the Libre doesn't match how you are feeling. It's nice to know then, that with a few strips and a fingerpricker in your pocket the Libre reader gives you access to fingerstick checks without the need to carry a whole extra bag of kit. On the whole though, the marketing claim is that you could use results from the Libre in place of almost all your normal fingerstick tests. I'm really interested to see whether I would have the confidence to do this so I'm currently testing at my usual SMBG schedule alongside Libre swipes to see what sort of differences I find. Those of us with more than a few years T1 mileage will already be aware that BG meters themselves are not exactly the most consistent performers, meter-to-meter or even strip-to-strip on the same meter.
The reader can also function as a bolus wizard in a similar way to the Insulinx or Accu-Chek Expert, though you need the support of a healthcare professional to get this set up and access this functionality. Like most meters the reader has an operating temperature range of 10-45C so while you can apparently scan through a ski jacket, you would probably need to keep the reader toasty in an inside pocket to avoid it grumbling about being a bit chilly. Battery-wise the sensors are unpowered and the reader is recharged via USB. A full charge is expected to last around 7 days of normal use.
As has been mentioned, one of the main differences between the Freestyle Libre and conventional CGM is that the data is not pushed by transmitter to the receiver. This means that the Libre cannot alert you with beeping/buzzing noises if your levels are soaring or crashing. This may be a significant concern for some, particularly when it comes to night-time, but part of me is quite glad. I always had a sneaking concern over how I would respond to a CGM repeatedly wittering and warbling to remind me that I'd made an almighty hash of estimating yet another buffet meal and that my glucose levels were still stubbornly stuck in orbit. The fact that the checking on the Libre is always initiated by me and can occur as often as I want it to is, if anything, something of a relief.
The handset offers a number of nifty, inbuilt analytical functions which can really help you to get your head around this avalanche of new data. I think I'm going to leave a detailed description of these for a separate post as I suspect many of you are losing the will to live by now. Briefly though, you can view results for 7, 14 30 and 90 days for Average Glucose, Time in Target, number of Low Glucose Events (where levels have stayed below 3.9mmol/L for over 15 minutes) or view a Daily Patterns graph, provided you have more than 5 days of glucose data stored. You can also export data via USB cable to be compiled into PDF reports and which can use something intriguingly called AGP (ambulatory glucose profiling). More on that later when I've got more data stored, but it looks really interesting. Helpfully several of the views display results grouped/averaged by time period so, for example, you can easily spot which time of day I've been having most fun with in the past 3 days.
What does it cost?
Abbott are offering a Starter Pack for £133.29 which includes a reader and two sensors. Otherwise the reader (on its own) costs £48.29 and sensors £48.29 each. These prices are ex-VAT so people would need to fill in the paperwork to get their VAT exemption on medical grounds. At those prices a full year's sensor coverage runs to just over £1,250 which is certainly not cheap, but when comparing with existing CGM options it is probably worth bearing in mind the significantly greater cost of handsets/receivers and transmitters for those options. Especially where transmitters are only guaranteed to last 6 months.
Freestyle Libre sensors/receivers will be available to purchase from Abbott's online shop from the end of September/beginning of October 2014 and once you have a receiver you could choose to buy sensors to cover as much or as little of the year as your budget allowed.
What has it been like so far?
In a word, amazing.
I have never had access to any kind of continuous data before, so I guess it was always going to be an eye opener, but I have been really impressed with the similarity between my standard fingerstick readings and results on the Libre. In a follow-up post once this first sensor has run its course I intend to do a little compare-and-contrast number crunching of the results, but already I am wondering what it might be like to more or less 'fly solo' with the Libre for the second sensor and only cross-check with SMBG if things felt wrong.
For the first time ever I have a full picture of what has been going on overnight every single morning. And if I wake up blearily overnight I am FAR more likely to swipe the Libre for an instant check than I am to get up, go downstairs and test. Not only that... but swiping the Libre does not involve turning any lights on or faffuing about with strips and finger-squeezing so there is far less chance of disturbing Jane in the rare event that my BG meter happened to be upstairs. I've already caught one sneaky overnight low that I am 100% sure I would have simply ignored/not checked via SMBG. Much comment has been made about the Libre for under 18s. Currently it is only licensed/available for adults but it was made very clear on Friday that Abbott are leaping through the regulatory hoops for a paediatric license as fast as they can. The phrases used were 'actively pursuing' and 'great need'. Sadly Abbott cannot predict the timeline, but certainly gave the impression that this was something they are already working towards as a priority. I can imagine that swipe-the-lump-under-the-duvet monitoring would hugely appeal to parents of children with diabetes who choose to test during the nighttime.
One of the other things I have already noticed is that the Libre makes glucose monitoring so effortless that I am inclined to check more frequently rather than less. Certainly in these early 'novelty' days. Part of this, I know is my own foolishness. I have been carefully logging and recording my BG levels, food, exercise and all manner of other details for several years now. It was one of the changes that made a massive difference to my own management and understanding of how my diabetes behaves and really helps me spot patterns and fix things. I made an agreement with myself early on that I would stick to a regular testing schedule and add in extras if things needed checking, but (importantly) that I would log every BG check I made to ensure I wasn't kidding myself by only writing down the good ones. Perhaps it's just me, but as noble as that set-up is I still find that there are occasions where I suspect I might be a tiny bit higher or lower than I'd like but don't want to mess up a good week's worth of results with another red flag so I'm tempted to make a small correction on instinct and hope to solve an imagined problem by the time I next test. This can be particularly the case if I'm having a week where I've had frustrating red flags peppering my results because results are 0.1 mmol/L past the cut-off rather than being real, proper, decent mess-ups. Yes it is silly. I know it's silly. But I do it anyway. And sometimes I end up treating a hypo-that-never-was and sending myself sky high in the process. Jane says it's because I am too much of a perfectionist. Too competitive with myself. And she's right. Again.
But with the Libre I am released from this - at least in part. If I want to check how a correction is going I don't need to wait until I think I'll be out of red flag territory. The curve on the graph will be there whether I check or not, so I might as well actually know. This, for me I think is going to be something of a Big Thing. Less double guessing and more data-driven responses. I may never play Uncertainty Tennis again while I have a sensor in my arm.
I am very interested to see how things progress over the next few weeks and will transfer some results into Excel (manually unfortunately as there is no direct .csv export from the Libre software) to try to understand how close or otherwise the results have been between fingerstick SMBG and Freestyle Libre. Unsurprisingly though, the trend arrows and graphs are already winning me over.
Does it replace fingersticks? My first few days certainly look really promising. Abbott themselves concede that there will always be at least some continuing requirement for good old fashioned punctured fingers. I'll write an update in a few more days with some of my own n=1 observations about numbers.
|Left-right: Me, Dave, Jen, Laura, Chris and Sue|
Aside from meeting the fab folks from Abbott and PR gurus WeberShandwick who laid on a really interesting and engaging event, one of the very best parts of the morning for me was getting the chance to meet face to face with some amazing folks from the #DOC. Jen (@missjengrieves), Laura (@ninjabetic1), Sue (@desangsue), Dave (@sowerbee) and Chris (@grumpy_pumper) are every bit as lovely as you would imagine. I look forward to reading their thoughts on the Libre later on.
Try these other posts too:
Laura (@ninjabetic1): FreeStyle Libre - Flash Glucose Technology
Jen (@missjengrieves): Freestyle Libre Review – a gamechanger for diabetes management?
Dave (@sowerbee): New Kit! - Freestyle Libre Review: Part 1