Thursday, 22 November 2012

HbA1c - A Good Measure?

(*pre-warning – I’m still old school and am working in percentages – to convert try here)

Every once in a while comes the judge of my success at being a person with Type 1.  As with most measures for us it comes down to a number. Whether it’s BG test results, number of hypos, waffy moments, total carbohydrates in a day, carb to insulin ratio, basal levels, etc, etc, it's all based around numbers. Here I feel advantaged as I quite like numerical stuff. My job involves a lot of Excel and that makes me happy. Hashtag = sad.  As a slight diversion I have real sympathy for any person managing diabetes who struggles with numbers. It must be an absolute nightmare to add to the challenge that we face. You have my deepest respect for the extra daily challenges involved.

Anyway, back to the HbA1c thing.  As the whole piece is about the test I thought it might be worth having a recap on what it is and what the number means.  

In simple terms it’s a measure of glycated or glycosylated haemoglobin  This is a form of haemoglobin that is measured to identify the average plasma glucose concentration over prolonged periods of time. Normal levels of glucose produce a normal amount of glycated haemoglobin  As the average amount of plasma glucose increases, the fraction of glycated haemoglobin increases in a predictable way. This serves as a marker for average blood glucose levels over the previous months prior to the measurement. There is a belief that it’s weighted towards the previous two to four weeks too. 

HbA1c is used by clinicians as a judge of control and can be a factor when considering treatment options including suitability for pumps etc.

Perfect then. Surely an average ‘score’ allows my team to see how well I’m doing at maintaining a good average BG level. Or maybe it doesn’t. As a numbers kind of guy I realise that an average, especially a mean is a very poor measure of numbers over time. For example the graph below shows 15 blood glucose tests (not me, I promise Doctor!) all outside a typical target range of 4-8 mmol/l (72 -144 mg/dl) yet the average is bang on the target at 6! Would you think the nine hypos here are a good thing?



And we’re not helped that our lows can’t normally go lower than around 2.5 whereas the highs can relatively easily get to high teens. How easy is that to skew an average? We haven’t got a chance really.

So where does my history lie? We’ll stick to recent times as that’s all I can remember relatively easily and records before then were written using multiple pens and both hands in the waiting room. So around March 2011 I was at 10.1%. A little hard work by me brought this down to 8.6%. A few months later and it was 8.2%. Fantastic downward graph that I knew I could keep improving before the bottom of the curve kicked in. Then Adam arrived and the first result last December came in at 7.6%. Absolutely chuffed about this and really proud that I’d hit the sevens. Especially proud as I know it’s not unusual for the first pump one to be a slight rise. I was convinced that further pumpwork would bring this to my target of 6.something without too much stress.  

The next test was around March this year and this again was downwards but not quite hitting my target. Still going in the right direction but I’ll admit to being a little disappointed with my 7.3%. 

And so the next blood tests were booked for last week and I turned up and volunteered my very generous veins to the nurse who duly removed a decent amount of blood and I left slightly squiffy (I never like my bloods being taken!) but still optimistic of a decent score.  Recent BGs had been good and floating around the waffy level quite frequently which should help the average.

Overall I’d say my control is a world away from where it was two years ago and the time taken with the help of my nearest and dearest is really making positive effects on my overall control of my condition. But – did you see that coming – I’m still not happy. On my personal scale of success at managing my condition I see anything starting with a 7 or 8 as failure. Which is harsh. I’ll speak with people online who are really struggling and trying their hardest to get under 10 and I don't think bad of them in the slightest. We each have our own personal challenge. I’ll encourage them and say that everything needs to be taken in perspective and they mustn’t feel like they have failed. At all. So for me to complain about wanting to achieve a 6.x is insensitive at best.  And on the flip I know of others who would view a 6.1 as absolute failure. An example would be Nigel Jenner from Diabetes UK as I recall here. It does come down to everyone’s target being important and at the same time each result isn’t a judgement; it’s just a very crude measure of something that gives the only real measure of long-term control without the use of CGM - I wish!

So it’s time to for me to reveal my score and also time for another graph! As I’ve said I was aiming for 6 point anything, with a previous measure of 7.3%. So after going to the Doctors’ Reception and asking nicely if my results were back I got the official verdict. Are you ready? Do you want to know what I was told? OK, here goes; “The Doctor has said Everything is 'fine'. Bye. Next.” No, no, no, no. No! My response surprised her a little bit but when I asked for a printout she seemed happy to supply it to me if only to get rid of the nutter in front of her – yes, that was me. So the two page printout of every detail of my bloods was returned and as always it takes a minute to find the number I wanted. There it was; the judge of worth and success of managing a condition that after 33 years I should have a grasp on. 7.2%. Yep, a massive 0.1% reduction. 0.1%! That surely is within permitted error margins. So effectively no change. Just to prove it here’s the graph to show the flattening of the curve.




After coming home, sulking and trying to find a bright side I turned to the oasis of optimism that is Google. Now apparently the target level for people with Type 1 is between 5.9% and 7.2% - depending on site visited. I was in! So why didn’t that cheer me up? I knew that to go online and sulk about ‘only’ getting a 7.2 would be a little crass. So I made comment about being a little down without shouting the number. It wasn’t appropriate; especially as the same day I was telling someone who’d just got a 8.7 that that was fantastic news for them because any progress is good progress, that they’d had less hypos and the HbA1c is hugely flawed as it’s an average. This showed to me I needed to go back to my first graph.  The numbers prove nothing really apart from that it really is a bad measure. But it’s also one that me, and others too, place a huge significance and fear on.

My control in the last year has been so much better and Adam has given me the freedom and flexibility I’ve never felt before. It’s this that I should be thinking of and realise that I cannot and should not be defined by a number.

Thanks for reading,

Dave

PS. I’m still desperate for my next one to start with a 6 though ;-)

11 comments:

  1. Nice article, one which many of us - even parents of a CWD - feel in tune with. It's okay to be a little disappointed as this will hopefully spur you on to achieve a lower result and a better quality of life. But don't be too harsh on yourself, 7.2 is still a good result and you don't want to get stressed about it.

    ReplyDelete
    Replies
    1. Thanks Kev. It's nice to know I'm not on my mine own in my thoughts!

      Delete
  2. Hey Dave, you've made huge progress and you still have a life - that's a massive achievement. And I bet if you look at the figures, rather than the crude average of an HbA1c you have fewer hypos and less time spent flying high? Both of which are probably more significant than HbA1c.

    You did good boy, acknowledge it :)

    (Sorry for the double comments, was trying to post as who I really am - Alison from shootup, but it keeps going to my old blogger account, I'll give up now!)

    ReplyDelete
    Replies
    1. Thanks Alison. But as the self-critical person that I am I'll either pick the HbA1c which is too high or the number of highs/lows which is too many.

      I know I should just accept it and move on. But I'm struggling to be pleased with an improvement; even if it's a tiny one.

      Hey ho, it's not like I wonder get another chance soon!

      Delete
    2. In that case, you're doomed. Give up now ;)

      Delete
  3. My last A1C was 7-point-something and I don't think of that as a failure. Mainly because I'm fantastic at everything and utterly wonderful in all respects.

    Alison's right though - the best measure of success is quality of life. There's a balance between spending all your time worrying / thinking about diabetes and getting "perfect" results and spending more time enjoying life without thinking about diabetes and getting slightly "worse" but still acceptable results.

    ReplyDelete
    Replies
    1. [Like Alison above, I couldn't post as Tim from Shoot Up either - I had to use my ancient Blogger account. Blogs, eh? Tuh!]

      Delete
    2. Thanks for the comments Tim. Apologies for the blog naffness. In retrospect I shouldn't have chosen Blogger but when I started Wordpress were losing people's postings so I thought it was the clever option. Hey-ho.

      Delete
    3. Life somehow struggles on though. It does mean my comments here are accompanied by an ancient picture of me in an Iron Maiden t-shirt, which is nice :-)

      Delete
  4. Dave I know exactly how you feel! I have set my A1c goal at 6.9 for now. I got my result the other day and it was 7.0. It has taken almost 3 years to get this far. I seemed to stick in the low 7's for the last 3 or 4 lab tests. Each one a little lower than the previous one. I know it's just a # and I should be really proud, because for years I was above 10! But that elusive "less than 7" is almost in reach. I try really hard not to live on the edge of low, just to reach the "magic number". I am proud of myself, and I refuse to get stressed about it. Even a drop of 0.1% means you are doing something right!! Congratulations!!!

    ReplyDelete
  5. Thanks for reading and commenting Kim. I love the way your experience is exactly like mine and that your last sentence conflicts with your own desire to drop quicker and further :)

    Good luck with the next one; I'm sure 6.anything can't be too far away for us now even if we both know the number isn't the important thing!

    ReplyDelete