Efforts are currently underway for global harmonization of the reporting of glycohemoglobin levels (%A1c is the current method for communicating average blood sugar levels over the previous 30 - 90 days) in terms of Mean Blood Glucose using the same units of measure as the common glucose meter. For various reasons, this effort has become somewhat controversial and I’m confident it will sort itself out.

However, there is already a way to approximate the translation of %A1c in relation to the method used in the landmark DCCT and to convert into mean blood glucose (MBG) in mg/dL, the same units of measure that people in the US are used to when using a glucose meter to check their blood sugar levels.

I must say that I’m very familiar with this translation for many years now but in approaching this topic, in discussion with my colleagues, we decided that publishing a complete translation table in increments of 0.1 A1c would be a useful exercise. This is the only table of its kind that I have ever seen taken to this extreme. Typically, you might see a table that shows you the translation in 1 full point increments at A1c levels of 5, 6, 7, 8, etc…

Until I looked at this table, I didn’t understand what all the fuss was about in wanting to communicate average blood sugar levels in mg/dL. A1c is already here and we know what it means so what’s the big deal. Right?

I was wrong. It finally hit me like a ton of bricks that nobody should be looking at an average blood sugar of 172 to 208 and be complacent with that level of control. That’s double the average blood sugar of a non-diabetic! Is it any wonder then that the American Association of Clinical Endocrinologists (AACE) disagrees with the American Diabetes Association (ADA) who recommends an A1c of 7.0 as meeting the standard of care (7.0 = 172 mg/dL), while the AACE is pushing for a lower target A1c of 6.5 (154 mg/dL) with talk of lowering it even further to 6.0 (136 mg/dL)?

So count me in on the side of converting to MBG as the right way to communicate with patients when discussing overall control over the previous 30 - 90 days. I don’t really care too much what the academics want to do but for working with patients, understanding the effects of your diabetes therapy and lifestyle choices on your blood sugar levels is much easier to understand when you use a familiar comparison and are able to reference the same unit of measure that you’re used to when checking multiple times per day with that little meter… and now with continuous glucose monitoring systems (cgms), this problem doesn’t go away. In fact, correlating cgms with its longer term counterpart measure will become even more important in the future as more patients move into real-time management. In a future post I will explain why. See if you might be surprised like I was by the translation of A1c into MBG by referencing the table below:

Mean Blood Glucose is derived using the DCCT equation:

(% A1c x 35.6 - 77.3) = MBG mg/dl ( r ) of 0.82.

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This entry was posted on Thursday, September 6th, 2007 at 9:53 pm and is filed under A1c, Behavioral, CGMS, Clinical. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.