June 27, 2006

Deluding yourself about the A1c

I went to the lab this morning in preparation for my visit to the endo in two weeks. As usual, she wanted an A1c and cholesterol test, though this time she also did a microalbumin and the cheap thyroid check (TSH).

That got me thinking about what a worthless test the A1c is and how it sucks that the A1c is the only test a lot of docs pay attention to.

The A1c is a very rough, indirect measure of average blood sugar over the recent months. What's actually being measured is how much glucose is stuck to your hemoglobin molecules. If you are anemic and have few of these hemoglobin molecules, your A1c may be deceptively low while high blood sugars are devastating your body. Many general practitioners don't know this. If your hemoglobin cells for some reason live longer or shorter lives than most people, you'll also end up with an A1c value that is misleading.

But even if the A1c is an accurate reflection of your blood sugar control, it isn't average blood sugars that cause complications--unless your control is so bad that your very lowest blood sugar level is well into the damage danger zone (over 140 mg/dl or 7.7 mmol/l). If your average is attained by going high for a few hours and then going low, you may easily end up with an A1c in the range that the lab flags as "excellent control", while elevated blood sugars during each of your spikes isflooding into your nerves, capillaries and retinas, setting you up for the classic, and very ugly, diabetic complications.

Relying on the A1c might have made sense 20 years ago when people with diabetes didn't own blood sugar meters, but now, when home testing is accurate and easy, it's another of the old fashioned medical practices that keeps people with diabetes getting old fashioned complications.


Anonymous said...

Your comments about HbA1c are very interesting but since you are an insulin using diabetic they don't apply to the majority diabetics.

Often, one can get far too involved in testing (and worrying) about blood sugar when perhaps other things are more important - for example smoking cessation, blood pressure and diet.

Anonymous said...

Surprised you haven't tried Byetta.

My fiance just started it a week ago and it's great! He hasn't had any side effects to mention to date and his hunger has deminished greatly.
He use to eat alot of carbs on sulfs and glitazones.
He has already lost about 4 pounds and controls are good.
You may want to check it out.