I don’t think they are synonymous, they are complimentary, in the same way a meter is complementary to CGM and both are complementary to the A1c measurement. On their own they are helpful, all three together is awesome. Can’t wait until we add low bg insulin shutoff and then eventually adjustable basal rates to the Dexcom data.
Agreed. It was stupid that the FDA made Dexcom take it down. I strongly suspect (based on absolutely no evidence) that a competitor had a hand in that.
IF the CGM system is providing accurate data then all the information you need and more is completely contained within the CGM data.
Am I satisfied with an A1c of 7.0? I can’t even begin to answer the question. I need to look at the CGM data and determine what is REALLY going on. If we don’t have CGM data then sure - the A1c is the best we have. The CGM is simply superior data. However it requires significantly more time to analyze and work with.
Long before the studies (which takes years to plan, execute, write up and publish) catch up we will be well into multiple vendors with FDA approved closed loop systems where the CGM is completely driving the entire process. The resulting A1c will simply be an artifact of that process.
I suspect when we finally get those studies we’ll find that CGM data may be a a pretty accurate predictor for most people, and that at least some of the risk that couldn’t be attributed to A1C may wind up being pinned to things like variability or at least hypoglycemia events.
But I also have a sneaking suspicion that if there are people who, for instance, consistently run higher A1Cs than their CGM data predict, that it’s possible they may wind up with elevated risk of complications compared to those with identical CGM average BG and std-dev, but lower A1C. Because ultimately A1C is measuring an advanced glycation end product – maybe not the one specifically and directly causing damage – but broadly speaking it’s directly measuring the physiological process which is suspected of doing the damage. Whereas average blood sugar does its harm via AGEs, meaning there’s some intermediate steps between those two that could confound the relationship between BG and complication risk.
Of course, that’s all wild speculation at this point and perhaps in 10 years nobody will even care about A1C.
In such a case, I would argue it is most probably that the CGM data is not accurate.
In that sense I find the A1c quite useful to validate the CGM data.
If the assumption is made that the CGM sensor data is accurate, I do not see how it is realistically possible for a person to have a statistically significant higher A1c then the CGM data would show.
Or maybe it IS…
I would actually look at this exactly opposite: am I satisfied with an average glucose of X and a standard deviation of Y? (Or any other cgm data?). I can’t even begin to answer the question. I need to look at e A1C to determine what is REALLY going on.
I don’t think so. I have never read anything which suggests that the red blood cells themselves cause damage. But certainly my reading barely scratches the surface of what is available.
My understanding (which admittedly is lacking) is the glucose molecule itself causes damage in the smallest blood vessels due to the size itself of the glucose molecule. But perhaps I have entirely misunderstood the cause of (potential) long term damage in this regard?
A1c will never tell me what is going on. So there was an A1c of 7.0 over the last 3 months. That really gives me absolutely nothing to go on. “Do better”. Ok… ???
I agree that the cgm gives you more actionable data and can give you much more benefit as to how to adjust and fine tune management, whereas the A1c doesn’t do that much at all. But the A1C is the actual tangible measure of the disease process and mechanism within the body… something that cgm data never can be… they’re not really comparable in terms of what they mean or which is more valuable. CGM is like a map for a road trip, A1C is the destination
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I disagree. The A1c is measuring an artifact.
Well, we already know that A1C numbers map to a wide range of average BGs – say from 126 to 141 mg/DL. We also know that some people with the same estimated average glucose can have A1Cs that run consistently higher or lower than predicted based on that eAG… this even with changing meters, meticulous testing protocols, etc. So I don’t think this variation is just down to the meter being wrong or the Dexcom functioning poorly.
We also know that people hang onto red blood cells for shorter or longer periods of time; people may be anemic or have other medical conditions that led to hyper-or hypoglycation. And healthier red blood cells tend to stick around longer, which means that as you get lower and lower down the A1C scale it’s possible that your A1C will get “stuck” so to speak, as those RBCs live long enough to get glycated.
In other words, there are physiological reasons why a person could accurately be running a certain average BG but still have a higher A1C than Clarity (used to) predict.
Almost no matter where you read about A1c the one word that pops up again and again is:
convenient
The A1c is absolutely the most convenient way to get a very good measure of the average blood glucose of an individual over the past 2 or 3 months. I totally agree with that.
What I completely disagree with is that the goal should be a “good” A1c. My goal is good blood sugar control. The A1c will fall out of that where it will.
When we go to the Endo with valid CGM data in hand for the past 3 months then I could really care less what they say the A1c is. I want to have discussions about how to identify areas for improvement based on CGM data and how best to implement those improvements.
An Endo that wants to talk about the A1c and is not interested in the CGM data is not one whom I will be going back to see again. Regardless of what that A1c is. I don’t care if the A1c is 5 or 15. It is simply not helpful in the presence of VALID cgm data. Other than it being one number which is very convenient to use.
This is such a huge topic. Suffice it to say that someone telling you the sugar molecule is damaging your blood vessels is a huge simplification, that is helpful, since it explains things succinctly and may get through to a patient, but isn’t near the complete story.
High blood sugar can damage your cardiovascular system, your nerves, tissue, kidneys, etc etc. There are many mechanisms of this damage, and there are numerous papers discussing associated changes that happen in large numbers of diabetics, for example this study talking about changes to the endothelial cells present in blood vessels in some diabetics and looking at a mechanism of damage.
I think there’s more too than that… the A1C isn’t just a snapshot, it’s the measure of how much effect ones glucose dysfunction are actually having on ones physiology…
But the point of discussion that came up in this thread:
Is it the glycated hemoglobin which causes the damage OR the glucose in the blood which is not attached to the hemoglobin? (Or some combination thereof.)
My understanding is the glucose itself causes damage while the glycated hemoglobin is an artifact of the blood sugar but not that which actually causes damage.
While what you said is true, it is again a simplification. Some people with low A1c’s will have diabetic complications, some people with high A1c’s will have no complications. When you look at an A1c over time in a population, we know what percent of that population will have complications, but we can’t predict yet which ones are at the greatest risk.
Therefore, it is prudent to keep the number as low as possible to minimize the chance of complications.
(I hope none of you all get offended easily. I enjoy discussions like this and hope I am not offending anybody.)
Sure but that’s true of all things in physiology. Some healthy fit marathon runners will die prematurely from heart attacks, some overweight smokers with high cholesterol will not… etc
I can say with confidence, that the glucose attached to your hemoglobin is not the cause of the damage in your body. It is the glucose in combination with the associated changes in the body that happen as the disease progresses. A1c is just a convenient and well understood measure that is correlated with the “health” of a diabetic, and can predict the % of the population that will develop complications.
How can we say this with confidence? Not disputing that it’s correct I just don’t understand how it could ever be proven… and how the treacherous glucose molecule suddenly becomes benign when it attached to hemoglobin and floats around for a few months instead of a few hours
Exactly, that is why I was objecting a bit to the A1c is a measure of the effect your glucose dysfunction is having on ones physiology. For instance if you are a person who needs a higher than average glucose value to glycolate your hemoglobin the A1c test would be under predicting your risk of complication. It is valuable, but by no means definitive.
Do a quick scholarly search on diabetic mechanism of damage to blood vessels, kidneys, nerve, cardiovascular system etc. You won’t find ones that are studying the effect of glycolated hemoglobin as a primary cause of damage.