Posted on 07/02/2009 12:12:52 AM PDT by neverdem
NEW ORLEANS — An international committee of experts has endorsed the use of the hemoglobin A1c assay to diagnose diabetes, at a level of 6.5% or above.
The 21-member international committee, chaired by Dr. David M. Nathan, was appointed by the American Diabetes Association (ADA), the European Association for the Study of Diabetes (EASD), and the International Diabetes Federation (IDF). Their consensus report—presented in a symposium at the annual scientific sessions of the American Diabetes Association and published simultaneously online in Diabetes Care—has not yet been officially endorsed by the three organizations.
“This is the first major departure from the way that we've been diagnosing diabetes for more than 30 years,” Dr. Nathan, director of the diabetes center at Massachusetts General Hospital and professor of medicine at Harvard Medical School, Boston, said at a press briefing held during the ADA meeting.
Since 1997, the cut-offs for diagnosing diabetes with either the fasting plasma glucose (FPG) or the 2-hour oral glucose tolerance test (OGTT) have been based on the risk for developing retinopathy. The committee reviewed available data and determined that the HbA1c assay was a better measure of that risk for several reasons.
HbA1c is a more stable analyte than is glucose. And importantly, HbA1c is more convenient as it does not require an 8-hour fast or a test that takes 2 hours. “It also correlated very tightly with the risk for developing retinopathy,” Dr. Nathan said.
The panel also advised that people with HbA1c values between 6.0% and 6.5% be considered at high risk for diabetes. However, they said that the term “prediabetes” is misleading because not everyone who meets those cut-offs will progress to diabetes, and some who are below the cut-offs will.
The document is only a consensus statement at this point, Dr. Paul Robertson, ADA president, emphasized. The ADA will now refer the paper to a practice group, which will review it to determine the medical, social, financial, worldwide, and other implications for changing the diagnostic criteria for diabetes, said Dr. Robertson, professor of medicine at the University of Washington, Seattle.
The document specifies the following for the diagnosis of diabetes:
▸ Diabetes should be diagnosed when HbA1c is at least 6.5%. Diagnosis should be confirmed with a repeat HbA1c test. Confirmation is not required in symptomatic subjects with plasma glucose levels above 200 mg/dL.
▸ If HbA1c testing is not possible, previously recommended diagnostic measures such as the FPG or 2-hour OGTT are acceptable.
▸ In children and adolescents, HbA1c testing is indicated when diabetes is suspected in the absence of both classical symptoms and a casual plasma glucose concentration above 200 mg/dL.
For the identification of those at high risk for diabetes:
▸ The risk for diabetes based on levels of glycemia is on a continuum. Therefore, there is no lower glycemic threshold at which risk clearly begins.
▸ The categorical clinical states of prediabetes, impaired fasting glucose, and impaired glucose tolerance fail to capture the continuum of risk and will be phased out.
▸ The HbA1c assay has several advantages over laboratory measurements of glucose in identifying individuals at high risk for developing diabetes.
▸ Those with HbA1c levels below the threshold for diabetes but at least 6.0% should receive demonstrably effective preventive interventions. Those with HbA1c below this range may still be at risk and, depending on the presence of other diabetes risk factors, may also benefit from prevention efforts.
▸ The HbA1c level at which population-based prevention services begin should be based on the nature of the intervention, the resources available, and the size of the affected population.
“To much of the medical community of America, this will not come as a surprise,” noted Dr. Richard Kahn, chief scientific officer of the ADA. “Many physicians are already using HbA1c with their own cutpoints for diabetes.”
Thanks for the ping, neverdem!
speaking of A1c...found this on Quest Diagnostics’ website: http://ir.questdiagnostics.com/phoenix.zhtml?c=82068&p=irol-newsArticle&ID=1295061&highlight=
Thanks, BFL
If you can’t get the numbers you want, you change the way you get the numbers. Sounds like a SHELL game. I know I have been going through this the last 15 years. You can not make MONEY if the numbers are to low.
Exactly. If you do some research, you'll see that they've recently lowered the numbers and now that allows them to give you a diagnose of a "high sugar" reading from that lowered threshold.
I think I also read somewhere that Canada uses a different threshhold.
I don't trust any of them.
You are, of course, free to be suspicious but more than half the diabetics in the country have not yet been diagnosed so the doctors should easily make up for you absence.
Apparently you did not read the article. The piece describes how different tests results can be interpreted to make a reasonable determination of a threshold.
The A1C has been used as a reliable indicator by my doctor as a reinforcing factor. This piece now reverses the order. The A1C becomes primary with the sugar level as a solid backup.
Do you know your A!C level?
Has it been determined?
If not, you are likely not at risk
Why? I’ve long criticized the futzing with the numbers - and this change is worse, to me.
instead of sticking with an inexpensive, instant test (plasma glucose), they have shifted toward a much more expensive laboratory test that is typically not administered unless sugar problems are at least suspected. How much money did the panel receive from the med lab industry?
The HbA1C gives inferential evidence of an average blood sugar. Therefore, they are endorsing the idea that a balance of high and low-sugar spikes is NOT diabetes? I vehemently disagree with this decision!
Think about this: The HbA1C can be “fooled” by semi-balanced highs and lows. The test is a measure of control, not variation. To me, diabetes is characterized by the variation in sugar levels.
I’m not a doctor, just a diabetic engineer. BUt I can’t say I agree with this push (much the same as I still disagree with the fundamental redefinition of the “diabetes” blood glucose ranges several years ago).
No I don't, and no it hasn't.
The way my Dr explained it at first is that you (the patient) can futz the blood glucose number temporarily. The A1C will tell him how I am doing over a longer period of time—making longer term management more effective.
I still measure a couple of times a day because I need that constant metric to make sure I don’t slip off the wagon.
Whatever works to keep it down is what I favor.
Yes, the daily numbers can be futzed. The two tests are complementary, in fact. My most recent HbA1C is helping to correct an issue with over-medication using insulin (it’s a long story).
However, it appears to me that they didn’t catch enough people with their plasma glucose range shift a few years ago, so they’re introducing a new way to spread the net. This way, they also include the med labs (or test kit providers) in the bonanza, too.
Yes - I’m cynical about “latest medical science”. I remember the “egg/no egg” back and forth all too vividly not to be skeptical.
Newly diagnosed diabetic (A1c of 10.9).
I am an opinionated, brash, sometimes loud-mouth (i.e.: engineer) who has been diabetic for almost 13 years now (HbA1C 6.6 in May).
Control is the name of the game. Are you type I or II? (None of your business is a valid answer, BTW.)
I’m type II, but now on insulin due to lack of control or decaying insulin production (probably lack of control - honestly).
Diabetes is considered a continuum, not a series of isolated events. Considering that all knowledge is to a degree imperfect, the A1C has been accepted as the best way to grasp the state of the continuum
I only have to get the A1c once a quarter, and my Dr doesnt even WANT me to take daily readings (I am very early in the process.)
The labs seem “reasonable” and he is not someone to run around prescribing a lot of tests. I don’t have a huge amount of reference in this. Are people getting the A1C more often than that?
While I agree with the A1c approach, the sticky part comes in with picking the target number.
As an example, blood pressure of 120/80 was considered ideal. Now it’s 115/75. I wonder how much input the pharmaceutical companies had on the new target?
The same can be asked with recommended cholesterol levels. If they’re not selling enough Zocor/Lipitor, then lower the target numbers.
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