HbA1c and Complications

[graham64]

Hi,
I got the following after following one of trinkwasser's numerous links, it opened my eyes about the dangers of high HbA1c numbers. If you've ever been told your BG control is to tight read on.

http://www.alt-support-diabetes.org/5%25club.htm

The term 5% Club was coined in a.s.d. on June 12, 2000 by a regular poster. It means that someone has gained excellent control of their diabetes and has received an HbA1c reading of less than 6.0%. Because our newsgroup is limited to ASCII text-only, the "certificate" isn't very pretty, but it is very meaningful.

Many have asked "Why 5%?" If one looks at the charts showing the risk of retinopathy and nephropathy, as developed in the DCCT and UKPDS studies, one will see a sharp increase in risk at an A1c of approximately 6.0%. Therefore, an A1c of less than 6.0% is evidence that the poster has done everything he or she can to minimize that risk. Remember, unless your lab is DCCT-calibrated, normal ranges do vary.

It is important to note that not everyone, especially Type-1 diabetics, will be able to reach an A1c in the 5s, so it should be regarded as a goal. Type-1 diabetics, and anyone injecting insulin, should weigh the increased risks of hypoglycemia against this goal.

 

[phoenix]

1)The point about type Is is important. I was able to get my Hba1c into the 4s, and to be honest I never had what is termed a disabling hypo. I was however becoming less able to recognise when I went below 3. I have since deliberately increased it.


2)
It is not just HBa1c which is the determinant factor in the development of complications. Its a whole package of what could be construed as 'healthy living'.
Look at the Birmingham retinopathy page. It shows graphs charting BP and the progression of retinopathy, another for smoking. Other factors include control of diet (evidence for fibre and 'healthy' fats slowing down retinopathy) , cholesterol (!), sleep apnoea and alcohol intake (raises BP)
http://medweb.bham.ac.uk/easdec/Information_for_patients.html
Since the causes of nephthropathy and retinopathy are much the same they often develop at similar times.

However it is not all doom and gloom, there has been a marked decline in the number of people developing these conditions. We often read that many people have very poor diabetic control , and certainly very few people are able to maintainHBa1cs in the 5s but both control and intervention is very much better than used to be the case.


3) NB the remarks belpw will only apply to a few people .

It is also possible to develop retinal problems by getting close control too quickly. (sadly a no win situation)
I have LADA and probably had it for 3 or more years before seeing a doctor. I quickly gained control and since then I have never had an HBa1c above 5.5%. A retinal scan at diagnosis showed no changes, yet a fluorescein angiogram 2 years later did. It is possible that more showed up on the angiogram. However, the opthamologist feels that it has have been caused by the rapid change in control (none to very tight). Luckily the last test showed no deterioration and it is to be hoped that this will continue. If you do have very high average BS It would be a good idea to read the advice contained in http://medweb.bham.ac.uk/easdec/retinopathyprogression.htm3)

 

[hanadr]

From what I have read, HbA1c> 6 is not the trigger for complications. It shows an average over 3 months. The real danger is "spikes". It's perfectly possible to have a low HbA1c with swings of Bg that go above 7mmol/l regularly. It's that 7 which is the tipping point. whereas the 5% target is good, it's not the whole answer. Achieving a 5% by keeping BG around 5.5 all the time is much better than swinging from 8 down to 3.5 on a regular basis. What complicates matters is that you don't know exactly what is happening between snapshot BG tests.

 

[graham64]

This is the link to UKPD its a comprehensive 10 year study involving 5000 Diabetics.

http://www.dtu.ox.ac.uk/ukpds/results.php

 

[brianb]

Hhhmmmmmmm this is interesting.

Im type 2 diet/exercise controlled and my latest HBA1C is 5.9 BUT i often get spikes of 12 Sometimes this is because ive been naughty and had a chinese or something other times it seems to have no cause. I am not low carb but have reduced them greatly and only eating salad, lots of veg and chicken etc. I am feeling really tired all the time which i think is prob due to the spikes.

Now i thought i was safe with an HBA1C of 5.9 but are we now saying that the spikes can cause damage as well?? :shock:

Brian

 

[The Governor]

Brian, it's more that the HBA1c is like a mathematical expression of your blood control, so by having spikes and lows it is possible to have a good average. Essentially you're "fooling" the test.

It's always the problem when working out averages in any equation... without overegging it, I would humbly suggest if you're seeing spikes of 12 you should probably have a bit of a rethink. I get fed up if I see a 7 in front of my numbers!

 

[brianb]

Thanks for that info Gov.

I do actually get a lot of lows as well 3.8 - 4.5 so you are saying that these could fool my HBA1C into looking lower than it actually is....Now how the hell do i convince my doc of this and what could his plan of action be?

Brian

 

[phoenix]

Since youdon't take insulin or one of the sulfonylureas , I don't think that you have to be concerned about the lower BG readings you mention. The spikes are a different matter.
It might be a good idea to look at your post prandial and fasting readings. If you note what you eat and the post prandial bg you should get some idea of how different types of meals affect your BS. It might also be worth noting any variation in exercise. Exercise reduces insulin resistance, a meal taken after exercise might have a very different effect from the same meal eaten after a couple of days being a couch potato!

 

[jopar]

HbA1c's can be so miss leading in the story they tell indeed more so for the insulin user... As it is only a adverage on the goings on over a 3 month period it does need to be look at with the day to day BG's as well....

My BG meter will give me a advarage of the tests that I've carried out over a 7,14 and 30 day period, But I will only use this information to see if my overall adverage is going up or down... If it's going up I need to be more predantic in my control if it's going down then I know that I'm on the right track.. I have noticed though with keeping a eye of this on the meter that when I have my HbA1c's done that it will normally come back around 2mmol/l lower than my meter suggests (at the moment I've got my fingers crossed as my meter is showing 7.4mmol/m as a adverage so that means I could be looking at HbA1c in the 5% range yeeppee) I find out next month

Having been getting HbA1cs ranging from 8% to 14% (highest 4 years ago then declining)over the last 20 years and being 9% at the begining of this year, I had no eye damaged, but June this year I started to use a insulin pump striaght into better tigher control and hey I've got eye damage that might require lazer treatment... A downside to good control, but even with saying that in the long term this will settle and hopefully stop in it's tracks so not too worried at present..

But alas there always seem that when you get a positive result, that there can be a slight negitive result lurcking undeneath...

 

[The Governor]

Thanks for that info Gov.

I do actually get a lot of lows as well 3.8 - 4.5 so you are saying that these could fool my HBA1C into looking lower than it actually is....Now how the hell do i convince my doc of this and what could his plan of action be?

Brian

You'd have to share your daily test results with your GP I would think, so at least he/she can see what your readings are actually doing. To do that you'd need to be testing at random intervals over a few days, but include test before meals, one hour and two hours after and keep a food diary.

Also, take a reading first thing after waking up, just to see where you start from. Don't panic too much if it's higher than normal at the start of the day, that's pretty common.

Sorry if that's teaching you to suck eggs, but just in case you weren't sure.

 

[Trinkwasser]

Thanks for that info Gov.

I do actually get a lot of lows as well 3.8 - 4.5 so you are saying that these could fool my HBA1C into looking lower than it actually is....Now how the hell do i convince my doc of this and what could his plan of action be?

Brian

http://www.alt-support-diabetes.org/NewlyDiagnosed.htm

That's the Gold Standard.

I've never had an A1c out of the fives.

Currently it is made up of the majority of my numbers being in the fours and low fives and postprandial spikes to the sixes and occasionally higher.

I used to routinely bounce back and forth between the 8 - 10 range and 4 or less several times a day, and curiously my A1c was actually slightly LOWER then.

Despite seldom running genuinely diabetic numbers I have some diabetic damage, and had particularly appalling lipids.

Some research shows that macrovascular complications are most correlated with A1c - these are things that require a certain amount of time at high BG to set in - whereas microvascular complications correlate to peak numbers, ie. the damage is pretty much instantaneous.

I think Jenny links to some of the research papers

http://www.bloodsugar101.com/

There are a lot of interlinked factors particularly with Type 2 including insulin resistance as hyperinsulemia can still occur with normal BG numbers.

 

[Berbatov]

I am quite confused now, not that I wasn't before. I thought, no lets correct that, my GP told me that the HbA1c is actual and you can not cheat it, it measures the actual glucose stuck to heamoglobin or whatever over the last 3 months.
:?:

 

[bonerp]

I dont know one single t1 that doesnt have spikes! Its not just insulin that controls spikes, but your hormones, mood, the weather, health, exercise, all sorts of factors.

I do my best to keep it within 4 and 8 - its hard. Stuff like this is almost demoralising!!!

 

[Trinkwasser]

I am quite confused now, not that I wasn't before. I thought, no lets correct that, my GP told me that the HbA1c is actual and you can not cheat it, it measures the actual glucose stuck to heamoglobin or whatever over the last 3 months.
:?:

This is true, however there are many other factors involved. Blood cells are glycated reversibly at first, so a brief spike will glycate them temporarily and they will then revert. This is NOT true of some other tissues. So it may underrestimate the potential for damage in people whose BG varies a lot.

Also the degree of glycation can be affected by other factors, not least high or low turnover of cells, some individuals are may show high or low A1cs compared to their actual spot numbers.