October 18, 2010

Massive A1c Fail. It does not accurately diagnose diabetes.

The American Diabetes Association's Committee of [Misguided] Experts has recently recommended that the A1c test be used for screening patients to see if they have pre-diabetes and diabetes. They suggest defining an A1c of 6.0-6.4% as indicating "pre-diabetes" and one of greater than 6.5% as diagnosing "diabetes."

Like almost every suggestion these so-called experts have made since they started -meddling in diabetes diagnosis in 1978 this one will condemn millions of Americans to live with undiagnosed diabetes for years--years during which their daily exposure to damagingly high blood sugars will ensure they develop the diabetic complications--heart disease, nerve damage, and kidney failure that prove so profitable to drug companies.

And no, this isn't my opinion. This is the conclusion drawn by researchers who looked at what would happen had a large pool of people being screened for diabetes been screened with the A1c test instead of the Glucose Tolerance test that revealed that many of them had diabetes or pre-diabetes.

The study is reported here:

Screening for Diabetes and Pre-Diabetes With Proposed A1C-Based Diagnostic Criteria Darin E. Olsen et al. Diabetes Care October 2010 vol. 33 no. 10 2184-2189. doi: 10.2337/dc10-0433

This team examined the records of 4,706 Non-Hispanic white or black adults without known diabetes. These people were given both A1C tests and a 75-g Oral Glucose Tolerance Test (GTT) when they participated in either the prospective Screening for Impaired Glucose Tolerance study (n = 1,581), the National Health and Nutrition Examination Survey (NHANES) III (n = 2014), or NHANES 2005–2006 (n = 1,111).

When the researchers compared diagnoses made using the oral glucose tolerance test with those made using the ADA's new A1c criteria they found:
The proposed criteria missed 70% of individuals with diabetes, 71–84% with dysglycemia, and 82–94% with pre-diabetes.
And if that isn't bad enough, they also found that
There were also racial differences, with false-positive results being more common in black subjects and false-negative results being more common in white subjects.
Applying the NHANES 2005–2006 data, the researchers estimated that,
... approximately 5.9 million non-Hispanic U.S. adults with unrecognized diabetes and 43–52 million with pre-diabetes would be missed by screening with A1C.
Unfortunately, such is the clout of the American Diabetes Association and its Experts, that huge numbers of doctors around the U.S. have already switched to screening patients using the A1c test. One huge factor driving this change is because doctors can earn extra money by administering A1c tests to patients in their office.

As documented earlier, these in-office tests are extremely unreliable. Details HERE.

But this latest study adds to our misery by making it clear that even accurate lab A1c tests miss most cases of diabetes diagnosed by the GTT.

So millions of people who ask their doctor if they might be developing diabetes will be given an in-office A1c test (billed by the doctor at five times its actual cost) and then be reassured by their family doctors that they are "fine" when, in fact, they are walking around with blood sugar levels high enough to damage their heart, their arteries, their nerves, their retinas, and their kidneys.

If you rely on an A1c to diagnose diabetes you can be certain that by the time that A1c has risen high enough to earn a diagnosis, you will have serious, even irreversible damage that could have been avoided had you only been given timely warning that your blood sugar level after meals is high enough to damage your organs.

To learn what blood sugar levels have been proven to cause organ damage visit this page HERE.

To learn how to test your blood sugar at home to find out if you are running blood sugars high enough to damage your organs visit this page HERE.

If you learn you are running higher than normal blood sugars you can lower them using this very simple technique described HERE.

If you are black, you may, conversely, be told that they have diabetes based on an A1c test when you don't. A growing body of evidence suggests that the A1c test is a poor guide to blood sugar control in black people, probably because of differences in the genes that govern their red blood cells.

A false positive diabetes diagnosis isn't as damaging to your body as a false negative, because if a false positive usually leads to you taking steps to lower your blood sugar. This helps everyone as there's evidence that even people whose blood sugar is completely normal according to the Glucose Tolerance Test have a significantly higher risk of heart attack if their blood sugar does not return to its fasting level by the end of the test. (You can read details of that study HERE.)

But a false positive may make it prohibitively expensive for someone misdiagnosed this way to buy affordable health insurance in the US and that, too, can be harmful.


Michael Barker said...

Good that you wrote this.
I wrote my last blog on just this topic.

I have sickle cell trait and my A1c comes out at 4.7, which doesn't match my meter. G6PD deficiency will give lower readings as well and that is the most common deficiency in humans.

I've been meeting with diabetes educators in my state and I'm trying to make the point that this is a very bad idea.

Jenny said...

A friend of the blog sent in this link. It's a MUST READ.

New York Times: Dr. Drug Rep (a Memoir)

Anonymous said...

Hello Jenny, first of all, thank you so much for your blog !

Due to another chronical disease, "doctors are not my friends", so consider my unfriendly attitude can play a part, but ...

I suspect this use of A1c has much to do with money and not that much with health.

With this new standard, you will be diabetic only from the level of A1C at which microangiopathy incidence induces expensive long term treatment (and, because doctors are also human beings, long-lasting sufferances).

But if you die of a heart attack (and suddenly stop costing anything anymore) as a "happy" A1C 5.9 "non diabetic", who will know (or care) that you ever were, indeed, diabetic ?

I'm a French, recently diagnosed type 2 diabetes.
I was intrigued by this strange difference between "pre-diabetes" and "diabetes" in the range 1,10 - 1,25.
Especially because ADA thought, at a time, of the possibility to define diabetes with this 1,10 limit.

I read that the 1,26 limit is not exactly what could be called a "true" biological limit, but rather a threshold at which social systems begin to consider you have to be treated (and begin to agree to pay).

If I had not consulted a diabetologist after my GP forbade (yes ... FORBADE) me to, I would probably not know that I'm truly diabetic, thanks (if I can say so) to a glucose tolerance test. And I had this test only after my fasting glucose jumped above 1,10, even from a diabetologist ... But A1C-ally speaking, I'm only 5.6 and never was higher ...

All this really recall me the "HIV-positive people will not develop an AIDS so, let's not give them AZT !" attitude at the beginning of the epidemy.