Leszek Czupryniak, MD, PhD; Bruce H.R. Wolffenbuttel, MD, PhD

Disclosures

October 25, 2012

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Leszek Czupryniak, MD, PhD: Hello, my name is Les Czupryniak. I am here in Berlin for the 48th annual meeting of the European Association for the Study of Diabetes (EASD). Our guest today is Professor Bruce Wolffenbuttel from Groningen, in The Netherlands. He is an endocrinologist and a worldwide expert on type 2 diabetes. Here in Berlin, he presented data on the relationship between blood glucose, hemoglobin A1c, and ethnic background, and I want to ask him how his findings might be relevant to our everyday practice. Hello, Bruce. What can you tell us about the findings of your study?

Bruce H.R. Wolffenbuttel, MD, PhD: We had the opportunity to look at a durable database, which comprised about 2000 participants worldwide who are participating in an insulin starter regimen trial. Roughly 60% of them were of Caucasian ancestry and the rest were of either Hispanic, Asian, or African descent. We found a variance in the hemoglobin A1c levels of about 0.3% to 0.5% between Caucasians on one hand compared with people of African, Asian, and Hispanic origin on the other hand. That is to say that these ethnic groups have a hemoglobin A1c for a given mean blood glucose that is 0.3% to 0.5% higher than that of Caucasians.

Dr. Czupryniak: This is highly relevant because it really complicates the practice of using hemoglobin A1c as a means to diagnose diabetes.

Dr. Wolffenbuttel: Absolutely. If you are Asian or Hispanic and you have a hemoglobin A1c of 7%, that [is roughly] the same as 6.5% in a Caucasian population. That is not only relevant for diagnosis of diabetes but especially for treatment of diabetes. For example, in the ACCORD study, [the goal was] to achieve a hemoglobin A1c of 6.5%, but that could be rather dangerous in groups of certain ethnic background, such as Hispanics or Asians.

Dr. Czupryniak: This is very interesting. We now know in the area of pharmacogenetics, for example, that some drugs may act more effectively in some [ethnic] groups than others, and now we [also find that] glucose control assessment should be somehow ethnicity based. This sounds very complicated. Do you think we will have various targets for various groups of patients?

Dr. Wolffenbuttel: I think that will be very wise. The differences [in response to medications and in hemoglobin A1c levels] may be explained by genetic differences between the ethnic backgrounds related to hemoglobin synthesis and so on. We also have shown that age, smoking, and use of alcohol are important in defining an individual’s hemoglobin A1c level. What we should really realize is that hemoglobin A1c is not a "gold" standard. At the most it is a broad standard with some "copper" mixed into it.

Dr. Czupryniak: Exactly. What about people of mixed origin? That makes this issue even more complicated as the number of people [of mixed race] is increasing. Any suggestions in this regard?

Dr. Wolffenbuttel: I have no data on that, but I would predict that people who are of Caucasian and Asian parentage would have a hemoglobin A1c relationship to their blood glucose that would be somewhere in between [that of Caucasians and Asians]. We need a methodology to ascertain for an individual what his or her normal hemoglobin A1c will be for a given blood glucose. Remember that if you look at a large group of patients -- let us say a group of patients with a mean blood glucose of 10% -- some may have a hemoglobin A1c of 7%, some may have a hemoglobin A1c of 11%. It is very important to look at hemoglobin A1c from a personal perspective, and what our data add to that is that ethnic background matters.

Dr. Czupryniak: The latest consensus statement from the ADA (American Diabetes Association) and the EASD tells us that we should individualize the strategy and treatment goals. They do not mention ethnicity in this document. They include 7 various domains you can look at when you decide how intensively you should treat the patient. Now we have an eighth [domain], so when we are deciding treatment in a particular patient, we now should also look at his or her ethnicity.

Dr. Wolffenbuttel: Absolutely. That should be in the 2013 update for the guidelines.

Dr. Czupryniak: These findings are highly relevant for our everyday work, wherever we work in the world. Thank you very much, Bruce.

Dr. Wolffenbuttel: You’re welcome.

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