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HbA1c to Average BG convertion

D

diabetesedulk

Member
Messages
5
Type of diabetes
Type 1
I heard in one of Dr.Richard Bernstein's video that the existing conversion table for HbA1c to eAG needs to be modified.
For an example ,According to Dr.Bernstein and a research conducted, HbA1c value of 7 equals to 172mg/dL (35.6x a1c - 77.3) with compared to 154 mg/dL in commonly circulated tables on the internet. In my personal experience 172 mg/dL makes more sense.
What're your thoughts on this.Following is the link to the 2 research summaries which had been conducted on to derive the 2 equations. http://www.ngsp.org/A1ceAG.asp
 
Hmm. I'm fairly sure the converter on this site uses the 2008 version rather than the DCCT out of date converter, based on ny results, what my libre says and what it gets.
 
tim2000s said:
Hmm. I'm fairly sure the converter on this site uses the 2008 version rather than the DCCT out of date converter, based on ny results, what my libre says and what it gets.
Click to expand...
Sure. I will have to read more about that I later realized Hba1c of 6% equals close to 7.8 mmol/L in that scale which is quite high as a normal BG level.
 
there could be a case to say that the conversion from HbA1c to average BG can be a bit of an individual sort of thing.

within the difference between the two numbers is the amount of tests and standard deviations of those collective tests to reach the median in an average.
 
They're never going to be accurate, because they're completely different measurements. HbA1c is a measure of glucose exposure, also known as Area Under the Curve. I work in pharma where I regularly look at exposure for drugs that I work with. If you look at a graph of blood glucose vs time, the area under the curve is the exposure that you have had to glucose. This is what HbA1c is measuring.

To talk of an average glucose reading is pretty meaningless. Average of what; BGs change constantly? A poor sample of 8 or so readings per day? Such poor sampling will never correlate well with exposure. If you measure 20 times per day, then maybe, but even then it will not be a strong correlation.
 
Another question about what the conversion actually means is that some people are high or low glycators. I'm a high glycator, worse luck.

My CGM/Libre data indicate a mean BG considerably lower than the equivalent calculated from my A1c. My mean BG for my last Libre sensor period was 5.5, but my A1c at the time was 41/5.9, which supposedly equates to a mean BG of 6.8. The Libre was generally within 0.5 mmol of fingersticks, but the gap is wider than that. This consistently happens with me, so it seems that I'm glycating more than I'm calculated to. I've moaned about this before.

So I don't think the conversion can be more than a guide. I think we have to decide what to aim for, and go for that.
 
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and just to throw a spanner in the works...............one person could run a HbA1c of 7.5% and have no complications, and another 6.5% but with complications.........

keep fighting the daily fight folks.....
 
diabetesedulk said:
Sure. I will have to read more about that I later realized Hba1c of 6% equals close to 7.8 mmol/L in that scale which is quite high as a normal BG level.
Click to expand...
According to the DCUK site calculator and the conversion table in the link, 6% equates to 7.0 mmol. So it's up to date.
 
novorapidboi26 said:
and just to throw a spanner in the works...............one person could run a HbA1c of 7.5% and have no complications, and another 6.5% but with complications.........

keep fighting the daily fight folks.....
Click to expand...


I remember @phoenix posting an article some time ago on the Joslin 50 Medallists, after 50 years of living with type 1 diabetes most of them had suffered no complications or had only minor ones, what was surprising is that the average HbA1c for this group was 7.1 which came as quite a shock.

Here a little info about the Joslin 50:

http://www.joslin.org/medalist/6268.html
 
Noblehead, Jason Fung has a table about the Joslin 50 which I'll try and dig up. He stresses that they seemed to be insulin sensitive (waist smaller than hips, no trunk obesity) and on relatively low insulin doses. And that A1c wasn't the point - their A1c wasn't stellar.
 

@LucySW, not familiar with Jason Fung but what the Joslin researchers found was after 50 years of type some participants were surprisingly still producing small amounts of their own insulin, which would explain why they would be injecting lower doses of insulin as this Fung guy is alluding to.

Have a look at the following, it explains how they came to this conclusion after blood tests found many of the group exhibit C-peptide molecules:

http://www.joslin.org/news/ultimate...in_50-year_medalists_give_clues_to_cures.html
 
So the question arising would be how we can help, or at least not hinder, our own pancreases from still producing a few b-cells.

As I said, what Fung drew from those Joslin studies was relatively high insulin sensitivity as shown by low insulin doses. Could that be related to still having some b-cell function.
 
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