Posted by on Wednesday 20 May 2015

Gimme 5 - a new hypo strategy

It is. Is it? Isn't it?
Here is a conversation I have had at pretty much every annual review I have ever had for my diabetes:

HCP: How many hypos are you having?
Me: Well... erm... that kinda depends on what you mean
HCP: What?
Me: On how you define 'hypo'. What you mean by it. What number or experience you use.
HCP: Erm... well... I... er...

You might think that it is a fairly simple question. Anything below 4.0mmol/L right? "Four is the floor" and all that.

Except that in the US it would be below 70mg/dl (3.9mmol/L) not below 72mg/dl (4.0mmol/L) - so suddenly there are a whole bunch of results that don't 'count' if you live over the pond just to make the US version a round number.

The matter is even more complicated by inherent meter inaccuracy. I have to say I trust my current Contour Next USB more than any other I have ever owned. Previously if I wasn't sure of a result I would immediately retest and could get a new result perhaps a mmol/L or two different in either direction. With my Contour Next USB, double checked results are more often than not *exactly* the same, or at most within a few decimal places. But this aside, ALL blood glucose meters are only legally required to work to within +/- 20% of a lab value. As I have pointed out before this can mean that your 4.0 (72) reads anywhere between 3.2 (58) and 4.8 (86). So which of those sub-4s would you count if some of them might be over 4 with a different strip or from a different finger? I can't spend my whole life (and all my test strips) triple-checking everything and taking the mean value...

But even if we set aside the imperfections in the data feed and assume that all the numbers are the actual numbers, it still isn't that simple. Particularly if, like me, you have ever experienced a degree of hypoglycaemia unawareness. Because you, dear non-diabetic reader, could be quite happily pottering along right now with a plamsa glucose concentration of 3.8mmol/L and no warning signs, and no one would care a hoot. For me and rest of the pancreatically-challenged horde though... things are different. If we don't get clanging warning signs at every 3.9 there is a breed of healthcare professional that will believe you are a danger to yourself, society at large and will be lucky to make it down the stairs without collapsing into a coma.

Don't get me wrong. I do not underestimate the severity of Impaired Awareness of Hypoglycaemia. Far from it. I have lived with it, and through it, and (particularly if associated with Severe Hypoglycaemia as it so often is) it is miserable for you, your family and everyone you are close to.

But if people without diabetes can be 3.8 and not hypo... then... well... er... Are we pancreas impersonators supposed to perform better than a fully-functioning non-D?!

Added to this - some guidance describes treating levels below 4.0mmol/L to avoid hypoglycaemia. From this standpoint 3.x-3.9mmol/L could be seen as offering a sort of 'buffer zone', a tiny whisker of breathing room before things might start getting messy. But 3.what?

This study suggests that most non-diabetic people will begin to experience some early warning signs in the region of 3.6-3.9mmol/L

While this study puts the level at which the brain begins to malfunction as 3.0mmol/L. And this, after all, is what we are actually trying to avoid at the end of the day.

But you don't have to have lived with diabetes for very long before you realise that the more 3.7's you have, the harder they are to spot. And the more likely you are to start getting 3.2s. And so on... and so on...

Plus ca change
And so it goes... I have some sub-4s, I try to have fewer. Some months it works. Other months it doesn't. Sometimes people are advised to 'run a bit higher' for a while (though there is little evidence that this relaxing of targets actually works to be honest). And I'm always caught by not really knowing how important a handful of readings between 3.5 and 4.0mmol/L are in the absence of Severe Hypoglycaemia and with relatively reliable warning signs that usually kick-in around 3.0-3.5mmol/L. And yet some clinic appointments make me feel like an abject failure for missing a 3.8 here or there. And the lower your HbA1c, the more twitchy your clinic tends to be about how many 'hypos' you are having - the very people who will be asked about your fitness to drive, for example. It's a quandary.

New strategy... Gimme 5
So as of this month, I have decided to try something new. I have been treating 5.0 as if it were 4.0. Any reading below 5.0 I have been treating as if hypo with fast-acting carbs (I have never been a follow-up carb person). And anything below 5.5 I have been treating more moderately with a smaller amount of fast carbs and/or a short sharp TBR - say 30-60 minutes dropped down to 10%.

Results so far are fairly encouraging. As an approach it certainly hasn't resulted in the general hike in BG averages that I have seen previously when trying to get rid of a few more of those pesky dips below 4. Hard to be sure and I'd have to run the system for a few more months but my best guess is that I might have lost perhaps 25-40% of sub-4 readings so far.

What do you think? Am I the only one who drives themselves nuts over this? How do you go about hypo-busting?


  1. Well I agree it's a confusing question. I regularly feel hypo symptoms below 5. I like to try and aim for th 4's but on days when i'm hitting that, I usually end up with a headache as it's like having a prolonged hypo. Science says I should be fine in the 4's, but my body tells me otherwise. I know of course it's due to my body being used to much higher blood sugars. It's only the last 6 months that i've really been getting anywhere near normal levels (mostly between 4 and 7).

    My biggest difference in dealing with hypos was through diet change and also coming off novo rapid and going on Humulin S. Much gentler insulin and although it meant the low carb life for me. I can now correct hypo's with a couple of glucose tablets instead of half a packet of biscuits.

  2. Thank you for the excellent analysis Mike, as ever.

    I liked the opening paragraph of the ADA workgroup paper:

    "Furthermore, the barrier of hypoglycemia precludes maintenance of euglycemia over a lifetime of diabetes; thus, full realization of the benefits of glycemic control is rarely achieved. Therefore, hypoglycemia is the critical limiting factor in the glycemic management of diabetes in both the short and long term (1)."

    The question about hypos at annual review covers several areas: have there been any serious hypos under 3.0 or recurrent mild hypos under 4.0. Really to see what can be improved with basal rates / bolus ratios / effects of exercise etc. The insulin clamp experiments on hypoglycaemic symptoms led to the DVLA recommendations not to drive with a BG below 4.0.

    Euglycaemic control without hypos is a fine line to tread. I'm sure a lot of us run high because it's so difficult to achieve, and just plain unpredictable on some days ...

    But I've found that it's readily achievable using a Dexcom G4 CGM with the hypo alarm set to 4.5. I really believe that this will be the gold standard for T1DMs within a few years. As more research papers come out showing better glycemic control using CGMs, funding for the hardware should follow. The NHS is just spending too much on diabetic complications, not to mention the personal suffering involved.

    Very best wishes,


  3. Thanks Ian, a thoughtful response as always. M