As you might guess from the title, I’ve noticed some changes in my hypo awareness, and I think I’d say that they’re generally in a good way. The last couple of times I’ve been to clinic appointments, I’ve been asked to fill in what I think was the Clarke hypoglycaemia awareness questionnaire, and I’d always stated that I started to feel symptoms around 3.5-3.8. That was pre-looping.
Pre-looping (but using CGM), my stats looked something like this, taken from the 31 days of May 2016, using CGM, maybe with a bit of HAPP and plenty of sugar surfing (this data uses 3.9mmol/l as the low level – red line – and 9 mmol/l as the high level – yellow line).
Those numbers are actually pretty good, but show a fair bit of time high and low. The standard deviation is also a little too high, at around 36% of the Mean. That’s not to say the Hba1C estimation is too bad, and in fact was reasonably accurate compared to the lab result. The ambulatory glucose profile at the time looked rather like this:
In the 25th-75th percentile bands, there are some clear low points showing up. The variability is also pretty obvious given the breadth of the spread.
Fast forward to a point after six months of looping, and we have a similar set of data, over 31 days, mostly covering February 2017.
The statistics are a significant improvement over May 2016, with 89% of time spent in the same target range, and only 2% of the time low:
This shows a clear improvement in glycaemic variation, and the AGP shows this up in a far more clinical way:
Clearly I still have few issues with lunch, but the rest of the time, that spread has reduced dramatically. The number of times there’s a drop below that red line is also significantly lower. My Hba1C is predicted to be marginally lower, but not dramatically, and the mean glucose level is also slightly lower. The other difference is in standard deviation, which has dropped to 31% of mean.
But so what? Well aligned with this tighter band of glucose results, I’ve noticed another, unexpected, phenomenon. As I previously mentioned, I wasn’t hypo unaware, but my alert level was around 18.104.22.168 mmol/l. Recently, I’ve noticed that I am feeling hypos at around 4.0-4.2 mmol/l. And when I say feeling them, I mean if I sit at 4.0-4.2 mmol/l for any length of time, I feel pretty that fuzzy headedness that many people report. I’ve double and triple checked with finger prick testing, and these haven’t turned out to be falsely high on the CGM.
Now, this wasn’t something I was expecting to see happen when I started looping. In fact, very far from it. But it has happened. And here’s the interesting thing. This doesn’t seem to be an n=1 phenomenon. I asked on facebook and gitter about other people’s experiences. Only a few people responded, n=10 in total. Out of that, 70% reported an improvement in sensitivity, 10% a reduction (but down from 4.5mmol/l to around 4 mmol/l) and two saw no change, although one of those had never felt their hypos. It’s a tiny, but interesting sample. If I was bigging it up I’d say that 78% of loopers saw an improvement in hypo awareness (but we know the truth!). Potentially, it highlights another beneficial use for moving people onto hybrid closed loop systems.
Importantly, it also provides some indicators as to what someone could do if they are struggling with Impaired Awareness of Hypoglycaemia (IAH). Admittedly, based on this unscientific sample of ten people, it’s hardly an RCT, but it looks very much as though, if you can reduce your lows (as we are always told) but also reduce your variability (and not run especially higher levels as has often been the advice), then you can adjust, or potentially recover hypoglycaemia awareness. Now the variable amounts of time that the responders to the survey have been using looping systems suggests that this means that recovery might not take as long as six months as well. That’s something that would need to be researched.
There’s a corollary to this tight banding of glucose levels as well. When you get to 10 mmol/l (180 mg/dl), you don’t feel so good. No, not at all. In fact you feel more like you remember feeling at 13 or 15 mmol/l. Which I guess is also helpful, in that it can drive behavioural change away from ever getting to those types of level, because you feel rubbish! Now really well managed people with diabetes that spend 95% plus of their time in range will tell you this is normal, and what else do we expect? Unfortunately, that’s not 95% of people with type 1 diabetes.
I’d be the first to say that this isn’t medical advice, and you should always seek HCP opinion before embarking on something like fixing IAH, but by doing what seem to me to be simple things, potentially, it might be possible to save oneself a lot of grief. I don’t think it’s new data, but it’s helpful to see that what we’ve been told about fixing IAH has a real grounding in reality.
So there we have it. If you do struggle with hypos, firstly, try and get your clinic to provide you with a CGM (even temporarily) so that you can identify what’s going on, and, annoying as it might be, use the alarms. Secondly, try to keep your glucose levels out of the lows, but also out of the highs, and you may see an improvement. It’s got to be worth a shot!