@Marie20, I sympathize with doctors that panic when they see a low A1C. It is more likely than not that the excellent A1C has been achieved with less than excellent control. Unfortunately, when I mention SD to doctors, I almost always get a blank stare. This is why I am so thankful for my endo. She lets me be.
For clarity, please let me add to my earlier comment. The A1c number is valid to compare with oneself but also when it refers to population statistics. Studies show a lower incidence of complications in a population when that population is < 7.0% A1c. For any single member of that population, that might not be true. Individuals can run their A1c > 7% their entire life and never come down with a complication. Conversely, individuals can live long stretches at < 7% A1c and still receive a diagnosis of a secondary complication. The population conclusions still hold true.
An A1c of 6.0% translates to an average glucose level that ranges from 100-152 mg/dL. You and I may share the same A1c but our glucose exposure can be quite different. Or I might have an A1c of 7.0% and you might have an A1c of 6.0% but my actual average blood glucose could be less than your actual average blood glucose.
The A1c for any individual is just not a very precise number. So that makes comparing one individual’s A1c to another’s is risky business. Valid conclusions just cannot be made comparing individuals. Again, The A1c’s value lies in its conclusions based on a collection of individuals or a population.
The glucose ranges that I cited above came from this 2016 diaTribe article. They, in turn, cite an NIH study.
@Terry4, many years ago I read an article that argued that lower variability is more important than lower average. If true, this might explain why A1C predicts complications for populations, but not for individuals. Most likely there is a positive correlation between A1C and variability and measuring A1C is just an imperfect and indirect way to measure variability.
Yeah, I agree @Helmut. Especially variability that includes any steep spikes or precipitous drops – they can really wear you out and cause hypo risk.
We learned eons ago that everything in moderation leads to a healthy lifestyle. A1C/GMI is just a number. 2 people can have the identical A1C/GMI with a huge difference in complications as these numbers just represent an average over the past several weeks. An individual with a small standard deviation (low variability) is at far less risk for future complications than a person with the same A1C/GMI and a high standard deviation, especially if coupled with many hypoglycemia events.
That is why what is really important is to set individual goals to continually improve control when able of both A1C/GMI and standard deviation. Your numbers versus someone else’s numbers mean virtually nothing. The only true bragging rights you have are the ones you have earned by beating your own A1C/GMI and standard deviation numbers against your own preset goals.
@Terry4 I had heard it varies .5% easily or possible 25 points off before. That’s a bigger variant than I had heard of before. I see that in the article about such a large variant.
SD doesn’t really do good on it’s own I think as you could have a low SD and be averaging 300. (unlikely I know) . That low SD won’t do you any good if your glucose is too thick. A low SD with higher numbers isn’t that great. If your blood is too thick it will still cause damage, you need something else to measure it with.
Eventually they might decide on a uniform TIR and a definite goal of how much time in range you should be. Of course you have to have a CGM too for that to be pertinent. That probably won’t happen soon either, although a lot more people are getting them.
And that brings it back to me that A1C is an important number to be judged on. They have to judge by numbers first, this person I worry about more versus this person seemingly is doing well. With the understanding that even if they are doing well sometimes things need to be addressed.
Which is also why my GP keeps telling me all diabetics should be on a statin, no matter what my numbers are…lol, it’s that group thing!
@CJ114, I absolutely agree that this is not a competition. Yet, I feel compelled to compare myself to others. I think the reason is that I want to strike a balance between living a normal life and becoming the next Dr. Bernstein. What effort is good enough? If I am running with the best, I am at ease. It might not mean that it is good enough. It just tells me that I have put my best foot forward and I can stop beating myself up.
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@Marie20, I think what @Terry4 is saying is that having 2 good numbers (A1C/average and SD) is better than just having 1 good number (A1C/average). I don’t see a meaningful difference between A1C and average. SD adds another dimension which might be equally important.
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Just in case!! Sorry @Terry4 !!! I was not trying to have an argument, just a discussion about it. I enjoy other viewpoints and why people feel that way! Please don’t take it the wrong way!!!
I agree that SD and TIR etc are important measurements. But I think I put more importance on an A1C number. I believe it is the first judgement of how well you are doing and maybe the only number an endo will see for a lot of people.
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No worries, @Marie20!
I agree that many people, including many doctors who should know better, begin and end their analysis of blood glucose management exclusively with the A1c number. That leads to the reflexive and sometimes invalid conclusion of too much risk of dangerous hypoglycemia based on a relatively low (normal, actually) A1c.
It’s taken many conversations with my endos to point out that my CGM data shows a low standard deviation (like 20 mg/dL) and an A1c in the 5% range with low BG variability as suggested by a low SD is healthy and safe. Well, as least as safe as T1D can be! I think clinicians are getting a better feel for CGM data but they don’t live with it 24/7 like some of their patients do.
Every time I get a physician knee-jerk hypo warning based on A1c alone, I push back because that overly simple analysis is not good for patients in general – especially in the context of abundant data. If A1c is the only data they have, I get their caution and erring on the side of safety.
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I went in armed with my CGM reports for 90 days because it is a relatively new endo and I didn’t know if I would get the lecture of you are too low. But she was delighted.
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I need my endo because I cannot write my own prescriptions. I am her only looper and was her only Dexcom patient for the longest time. Her other patients live on another planet. She is frustrated that she cannot even get them to meet ADA objectives. She makes a living by treating complications. I hope I never need her expertise.
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It is interesting isn’t it, that we on this board are probably only part of a small group that pay so much attention?
One of the diabetic helpers said when I stated, I’m retired I have more time to spend on correcting high’s etc, she said the other retirees she knows don’t care.
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Anybody who is on this board is a standout. Some of us push the limits for the joy of it. I consider it a blessing if joy aligns with healthy life style.
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Someone, way up there somewhere, asked why Dexcom moved away from displaying A1c and went with GMI instead. That was the honest thing to do because an A1c is not based on average blood glucose derived from blood / interstitial glucose readings, which is what a Dexcom is doing. Instead, an A1c directly measures the amount of glucose bound to hemoglobin in red blood cells over the cell’s approximate 90 day life span. So, reporting an A1c based on average blood or interstitial fluid content would be like reporting BMI based on clothing size - in the ballpark but disingenuous and not very scientific. Dexcom reporting GMI instead allowed them to report a metric based on known data derived from their device.
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I think you nailed it, Helmut. Dexcom’s A1C estimates were proven to be significantly off when patients actually had their A1Cs checked by a doctor, so they came up with their own measure. Bottom line: it’s helpful but not infallible.
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Maybe I’m lucky and have an endo and CDE that understand the technology and it’s capabilities. As soon as I walk into the office the first thing he does is download Dexcom data for the last 30 days and reviews it with me along with any other health concerns. Only after that discussion (and it is a DISCUSSION, not preaching) will we arrive at an action plan. I don’t think the numbers mean much to him other than perhaps comparing it against my past results.
My endo may have a more engaged patient base which lets him approach things this way. There are not too many good endos out there in this area and I suspect those types of patients seek him out. Others diabetics may not care as much. In fact most of the people I know personally who have diabetes are that way. The people on this forum are the exception, not the rule.
My last A1c from doctor’s office in September 2019 was 5.5, compared to Dexcom GMI of 6.2. Recent A1c from an OTC product test of 4.3 but do not believe it until it confirms at next appointment. Dexcom Clarity 90 day average 120.
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Very right. A1C is just one test value to summarize what has happened in 3 months, G6 readings are large amount to data that truly reflects the details of what has happened in 3 months. Both are valuable and somewhat related. It’s one’s own decision how to interpret them and make good sense out of it to guide glucose management
I have the same experience. My dexcom predicts 6% and I’m usually around 5.5%
I generally trust my time in range over anything else.
Cgm has really put a magnifying glass on the limitations of a1c.
If your nights are lower than days, you will see a disparity with a1c because red blood cells are manufactured mostly at night.
Also if you are dehydrated or if your red blood cells are higher concentration or lower, will really effect the test.
I try to be fasting 8 hours. And I drink 2 glasses of water in the morning before my test.
I still get a result that .5 lower than expected, but I’m as consistent as I can be.
Some people aim as low as they can be on a1c, I’m happy where I am. I focus on time in range. I’m hoping to avoid complications this way.
A year ago, I was happy with a 6,7 or a 6.8. But I wouldn’t accept that anymore, now that I have better tools.
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