A1C: predictor of side effects

My partner (type 1) and I just got back from the endocrinologist. As he has in the past, he insisted that because my wife’s A1C is good (below 7), she’s doing fine. I pushed him on the issue, asking him to explain how it could be that an average is so relevant, when it could disguise serious control problems that are averaging out (my wife has lots of serious highs and lows.) His response: there may indeed be serious fluctuations, but the data simply indicate that regardless of that issue, people with A1Cs consistently below 7 just do not incur complications later on.

I’ve read contradictory claims, and I’m very interested in what others have to say about this issue.

I agree with you. If someone has a good A1c (& what’s good is debatable) this is not a true indicator of how well BG is controlled. As you said, it’s an average. Ten people with identical A1cs can have vastly different BGs, with highs & lows balancing each other out numerically.

More important that just A1c is your wife’s standard deviation. Keeping BG as level as possible & as close to normal as possible is the best route. Since you mention she has serious highs & lows her insulin ratios, timing of doses & diet need adjusting. Bouncing from high to low is damaging.

Good endos look at patient logs, not just A1cs. If she’s not, your wife should be recording her readings & doses to fine tune.

I don’t believe there is any crystal ball and I do believe her genetics will also play a huge part in a complication free life.

I hope what your endo says is true, but I wonder how he came up with such a broad statement.

I’ve had a lot of trouble in the past with endocrinologists telling me I’m doing great because my A1c is under 7, ignoring my huge blood glucose swings. I think part of the problem is that they see so many patients who are in such poor control that someone like your wife, by comparison, seems like she is in great control. You are right to question him.

I agree with Gerri…I had good A1c’s before I went on a pump but it was because my lows averaged out my highs and I know look for a good A1c along with the SD (standard deviation). If you can keep a good A1c and a SD of around 25 give or take a little bit I think that this is as good as you can get. I’m not really sure how to calculate the SD but my Co-pilot software keeps track of it for me, if you use a freestyle meter or one from Abott you can download your meter data to it and I’m sure other meters can track this. I never paid much attention to my SD until another user explained it and I still not sure but just know that the lower the SD the smaller the range from your lows to your highs are. If you have good SD then I would say your endo is right for the most part.

Hi Judith…You just threw out there something I don’t know again. I’m very new to this and have only had T1 for a little over 2 years and just started to keep track of my Standard deviation along with my A1c number. So can you explain the T2/GP Level? Just wondering what this is?

Thanks for those helpful replies. The logic is clear to me, but what about the data? Standard deviation seems like it should be a more meaningful stat than the mean of the A1C, but our endocrinologist maintains that his position, counterintuitive though it may be, is supported by the data. I’m about to embark on a search of the literature to see if it’s consistent with his claim, but if anyone can offer a shortcut by citing a study or two, I would be grateful.

There’s research that A1cs below 7 are the better than above 7, but that’s meaningless. An A1c of 6.8, for example, is an average BG of 149. That’s not acceptable to me. One issue is that standards for what’s “good” aren’t high because many medical professionals don’t believe diabetics can do better.

If your endo believes your wife is doing well with swings from high to low, it’s time to find another doctor rather than arguing with this one. Show him her logs & ask him to explain what the risks of a BG rollercoaster are.

Our best chances for living a healthy life is to aim for BG as close to normal as can be achieved. Find a doctor who supports her goals & will take the time to adjust her insulin & provide guidance.

Thanks, Gerri. I’m still interested in the hard data. Is there research that shows that with A1Cs below 7, there is markedly less risk of complications, to the point where swings are not significant? Is there research that shows the opposite? Your opinion makes sense to me, so it’s not a matter of not understanding the argument, but I want to find the studies that show the data.

I’m not aware of research that shows that swings are not significant regardless of A1c. Swings are always significant, not to mention how exhausting these are for your wife.

There’s research to show that BG consistently over 140 causes damage. 140 is the number commonly cited. You can start by checking out www.bloodsugar101.com for studies & data. Check out her blog also. Another excellent source is Dr. Richard Bernstein. He’s been at the forefront of demanding that diabetics should have normal BG.

There are simply no guarantees that any A1c is assurance of no complications. What a ridiculous statement!

The blood glucose of a healthy person is very tightly controlled. As type 1 we will not always achieve this level of perfection. So despite good control we have spikes all healthy people do not have. Let us assume we will reach a healthy A1c of 5.5. Will this prevent complications? Well, it should but there are no guarantees because of the spikes we have. This is some sort of background stress that is not present in healthy people. Stress means that cells get hurt and need to be rebuild. To be damaged by high glucose numbers and to be able to repair these damages are highly individual capabilities - mostly genetically controlled. Long term studies try to identify these factors but I am asking myself what people should do when their genetic predisposition is less promising.

The likelyhood for complications is significantly lower the better the A1c. One big drop of likelyhood seems to appear around the 7 mark but still the likelyhood is just too high. Strieve at below 6.3 and you will have to address mean glucose and its fluctuations at the same time. You can not reach 6.3 with many spikes and this way you will optimize in both directions.

My endo always looked at the A1c and the number of lows. When I had a 6.5 with almost no lows – this was considered great. If you can get your A1c down without adding lows, then you are doing great.

Another important factor (apart from complications) is that if your wife is having serious highs and lows, this is very tiring. If she can find ways to reduce the variation, I’m sure that she will feel better now and give better chances for the future as well. Even if she is doing fine, that doesn’t mean that she can’t do better.

But I also think it is important to recognize that it takes a lot of work to remain below 7 and even more work to improve that and lower the standard deviation – so your wife deserves some praise :slight_smile:

Right level of A1c?? well it depends whom you are talking to, at least until 2008. american diabetes association (ADA) stipulated a tighter control for A1c at < 6.0 while the International diabetes federation (IDF) said that an A1C < 6.0 would mean the patient is experiencing periodic and repeated lows and this is detrimental to his health. Hence the IDF recommends a value of <7.0.

what do i follow?? i am from India and we follow IDF. But then i stayed in US for 5.5 years and during this time i tried to stick to < 6.0 (i was told to follow ADA regulations by my doctor) and it was very difficult for me to maintain that. The reason, every time i tried to do it, my sugars started to gradually decline into 50s after 2-3 days with the same dosage.

But then all these standards were based on results prior to insulin pumps becoming popular and acceptable with the insurance companies.

what changed now?
with more results available from real life studies becoming available in 2008, it has become clearer that what is more important is the SD. Its ok to maintain an average of 130-140 or 150 as long as you have a low SD. Starting 2008 the US govt through the FDA and ADA had instructed the doctors in US to not entirely rely on A1c as a means for judging diabetic control. At the same time insurance companies started approving pumps more easily and hence it was much easier to maintain a much tighter control without lows and along with that today’s most co-pilot software was also upgraded and started measuring the SD.

hence while i was in US in 2009 i was told to move to a pump a.s.a

I am sorry that i do not have the links to these studies with me anymore. Further the new policy change is a guidance to the doctors and it is not a mandatory policy change.

Kristin is right, and I should have said this earlier, too–your wife definitely deserves praise, whether or not your endo was completely right. An A1c under 7 isn’t easy to achieve. Diabetes isn’t an easy disease. I agree with everybody–try to find another MD or nurse practitioner who will help you tighten things up, but as Kristin says, your wife should congratulate herself for how much hard work she is already doing!

We are much more than our A1C’s.

The DCCT data shows a steep knee in complications above an A1C’s and that’s valuable data resulting in the commonly quoted 7.0 (but recently 6.5) A1C goal. But it does not mean that being below 7 has zero risk of complications. Indeed, for the longest term followup DCCT studies it is clear that there is continued benefit in reducing complications from getting the A1C as low as 6 or 5 if possible to do so safely.

The A1C is a valuable summary of average bg and the DCCT and followup studies show that for the common microvascular complications, the average bg is the best determination of that risk.

But I said “that risk”. Hypos can still be life threatening and are a different risk, also measured by the DCCT. And the DCCT found a very huge risk for increased hypos at lower A1C’s.

Many believe that the hypo risk can be mitigated through not just controlling average bg’s, but also working hard to keep the high and low extremes in check too. And your doctor ought to be giving you support to keep those in check. Frequent bg testing, improved insulin delivery methods (e.g. pumps), and CGM’s are all tools to help there. Your doc really ought to be helping you avoid hypos too.

Most doctors will try to “explain” stuff to you by quoting standards of care developed by so-called experts. This includes the ADA and for an endo groups like the AACE. These standards are developed by getting a whole bunch of senior “experts” together and they basically vote on stuff, a far cry from why I consider “evidence based medicine.”

In terms of our understanding of the relationship between blood sugar control and complications, the last really major US study was the DCCT in the 90s, and that showed clearly the benefits of reducing down to the 6s, but they did not include a more intensive group, so it said little other than you know that getting down to 6% is good. The UKPDS study which seems to be one of the better studies out there included a group of HbA1c < 6% and found not surprisingly that all the rates major complications that they looked at were highly correlated with HbA1c and that the relationship continued below 7% AND below 6%. There is a good summary of part of the study (http://www.bmj.com/cgi/content/abstract/321/7258/405). The EPIC Norfolk study showed that the risk of CVD doubles by the time you reach 6% (http://www.bmj.com/cgi/content/full/322/7277/15). The E-N study also included a cohort in the 4%s and the risk reductions of complications continued down into this normal range (not surprisingly).

The corruption in the US system has resulted in few studies of the efficacy of aggressively lowering blood sugar levels without intensive harsh medication like Actos and Avandia and certainly no lifestyle modication. Perhaps it is just not good business. Even with the ACCORD study, the excess deaths were not due either to hypoglycemia nor to insulin.

I would also note that as a patient, you should understand these rates of complications in context. Your CVD risks “double” already by the time you reach 6%, yet we are constantly told that we are going to die from high cholesterol. I’ll leave you with a question. Exactly what is the risk from high cholesterol (hint: it is much lower than double)?

And personally, I think that tight control of variances is as important as the average (HbA1c), but there has been almost no study of the issue. Jenny at bloodsugar101.com advocates keeping your blood sugar below 140mg/dl with the argument that damage occurs above that value and is proportional to blood sugar values. If you read through her material, she shows a number of studies that show damage starts to occur at that level and leads her to advocate keeping your blood sugar below that level all the time.

OMG - did an endo or a GP say that? If you have fluctuation - you will normally get a good A1c and this is not a prevention of complications at all. This was discovered predominently when insulins like Lantus and Levemir became available as basal insulins (that in comparison to NPH (older insulin which is variable in action and has massive peak - in fact causes swinging) , the newer insulins decreased the low fluctuations, hence the new average (A1c) for people with swinging sugar levels went between normal and high which created an actual higher A1c. (does this make sense) At first this was concerning for Drs, (they thought these newer insulins gave people higher A1c, when suddenly the penny dropped - the window for swinging is smaller in a higher range on the BG scale), taking away the lows. (minimising hypoglycaemia). It is really important that you try to minimise the swinging by implementing some of the following:

  1. If it suits and can afford - go on a pump
  2. Use modern - relatively peakless basal insulins and modern fast acting insulins
  3. Learn to carb count correctly and know your insulin to carb ratio - When you have 15 grams of carbs or 1 exchange, how many units of insulin is needed
  4. KNow your correction factor - how much 1 unit of insulin will lower your sugars - this will minimise your swings too
  5. Dont over correct a hypo - people get scard and have way to many carbs sometimes.

How arrogant of your Dr to sit there with one measuement in mind for your health outcomes - i would find a new Dr myself

I’m not aware of a study that provides a concrete answer for your question like the DCCT did for A1c. I’m sure that there will be one, especially with CGMS becoming more widely available, but studies like the DCCT take more than a decade to complete because complications take time to develop. In that sense, 10 years is actually a short time. However, I agree with the others, it seems common sense that we need to try to mimic the natural biologic process as closely as possible. I’m not sure why your endo doesn’t see it this way (but assume he may be burned out).

At the very least, major fluctuations raise acute risks associated with highs and lows. They also can also affect quality of life, from work to social situations. I’d strongly advise you to see a new endo or one of the NPs that might help. At my last endo, there was only one endo that I liked but 2 NPs that were extraordinarily helpful.

I also don’t like your endo’s view of 7 as the magic A1c. It isn’t. It is the average of the ‘tight control’ group compared to the (at the time) conventional group, whose average A1c is around 9 and experienced more complications. That is where the number came from, 7 is better than 9. It’s better than nothing, but it’s by no means magic. I get really annoyed when people over-interpret the data. It’s just as easy to look at the graph of risk of retinopathy v A1c – the raw data don’t show an increase until above 8% if I remember correctly. But I don’t hear anyone arguing (nor should they) that < 8% is the best target.

In fact, I think a lot of the advocacy groups are pushing for a new goal of 6%. The goal should always be individual-specific, but that is best determined by an endo that you trust. Nothing is more important than that.

I just saw a presentation on the internet that indicated that different A1Cs are now being advocated for different sets of people. This presentation was only about type 2 so less relevant here, but while those with many cvd risks had higher rates of mortality when treated intensively to lower bgs, newly diagnosed diabetics without many cvd risks had long term benefits, lasting like 10 years, from having bgs as close to 6 as possible. The upshot of the presentation was that people with longstanding diabetes, complications, or a short lifespan should shoot for an A1C of 7 or above, whereas the new people should try to get to 6 or below.

If the presentation you saw was citing the ACCORD study, this was horribly flawed research. The ACCORD study subjects were people with existing heart disease. The subjects were given a combo of drugs that were known to be risky. They were also forced to eat a very high carb diet. I can’t imagine a worse scenario.

There’s ton of studies out there. Without reading the actual study,examing the methodology & finding out who’s funding the research, it’s meaningless. Unfortunately, the ACCORD study grabbed headlines & doctors were telling patients to raise their A1cs. Utter insanity!

I’d run from an endo who told me to have an A1c of 7 or above.