How much sugar you ate does not have any bearing on whether you are a diabetic.
I didn't say it did. I thought I said it's about how your body
responds to sugar (insulin release for one). But to measure your body's response, you have to know how much sugar you ate.
HgA1C measures the effect of your sugar levels on your body. It measures glucose levels integrated over an extended period of time. It's a much better representation of the diabetes question than any point measurement like a fasting glucose or a challenge test.
Once again - yes of course it's better than
any one point (snapshot). I never said it wasn't. But it's not better than many snapshots over time. It's worse, because it's averaging everything out rather than giving you a complete data set.
The A1C cannot differentiate whether you ate a million pounds of sugar and your pancreas put out a million pounds of insulin to keep your BG at x, or you ate very little sugar and your pancreas barely kept up with it to keep your BG at the same x.
That same x might have the same effect on your tissues (although I submit it doesn't) but those two pictures are not equal. The load on your pancreas (liver and everything else) is vastly different between the two.
The A1C assumes that the total area under the curve is what matters (or over the curve if you will, over whatever BG is not damaging). Twice the amount of time spent at half as much over a safe BG is equal according to this assumption. I say: Not true! Studies show that the level at which tissue damage begins to occur is 140 mg/dl. It matters whether you keep your blood sugar below that number all the time, or whether you have peaks during the day where it stays above 140. Balancing those peaks with low levels
does not mitigate the damage done by the peaks. This is why it's important to have multiple data points over 24 hours and over many days. This gives you a much more accurate picture of whether you're being damaged by glucose than an average over the same time frame.
Again I stress this issue occurs only close to the borderline for a diagnosis. A very high A1C no question you're diabetic and being damaged, a very low A1C it would be extremely difficult or impossible to be having high BG peaks counteracted by enough hypoglycemia to get a low a1c.
I have no issue using A1C alone to diagnose when the doctor catches you walking around with 600 mg/dL. I do have a problem giving the diagnosis at 6.5 to everyone without further investigation of that individual.
But I'm not saying don't treat the person who is 6.5; I think PRE-diabetes should be treated the same as diabetes; the goal should not only be to get your average down, but also to reduce peaks, and focusing on A1C just completely blinds people to their peaks.
When a patient comes to the doctor at 6.3 that doctor should order that patient to buy a test kit and do daily fasting and post prandial testing and that patient should be scared to death if they see 150 on the glucose meter. But they should not receive the diabetes code in their record, unless confirmed by a GTT. Conversely at 6.5 the doctor should advise the exact same thing, AND do further testing to see whether the patient actually meets a GTT criteria before hanging them with the hard diagnosis.
I realize I'm probably in a tiny minority of people who don't want a diagnosis code just to pay for test kits and strips. Most patients, "Sure! Code me so my insurance will pay!" And doctors are happy to comply so I realize I'm just beating my head against a brick wall here. But us pilot people really do care about such things, at least before BasicMed.
).
