Dr. Ralph Defronzo talks with Diabetes in Control Publisher Steve Freed during the ADA 77th Scientific Session in San Diego about the usefulness and the problem with the A1C test.
Dr. Ralph Defronzo, MD is Professor of Medicine and Chief of the Diabetes Division at the University of Texas Health Diabetes Center in San Antonia, Texas. Dr. Defronzo is also Deputy Director of the Texas Diabetes Institute.
Transcript of this video segment:
Steve Freed: You’re one of the first people to recommend triple therapy because you’re very aggressive with your treatment. One of my favorite questions that I always ask at the end but I don’t want to forget so let me ask you know is when you go downstairs into the display room, they’re going to be offering free A1C tests. You go there and they stick your finger and they get a drop of blood. In a few minutes they get a result on a piece of paper. They’re going to hand it to you and on there there’s going to be a number. It’s not going to say “below 7”, it’s not going to say “between 5 and 8”, it’s going to be a specific number with a decimal place. If you can have any number, regardless of your health, if you can have any number, what would you want your number to be for your health?
Dr. Defronzo: I would like it to be somewhere between 5.0 and 5.4. A1C is a very useful test because you can get it any time, even if the person is not fasting. So that means, we do a lot of screening, people can just walk into the clinical research center and you don’t have to have them fast it overnight. You don’t have to do an OGTT. But there’s also a problem with the A1C. Of course if it’s markedly elevated you know you have diabetes. But there’s an intermediate range. We’re looking at a 5.7 to 6.4. So we have this term prediabetes. It’s a term that I don’t like because you can either have impaired glucose tolerance, which means an elevation in the two hour glucose during OGTT or you can have impaired fasting glucose, which is an elevation in the fasting glucose. Of course you could have both. So the A1C doesn’t tell you which of those two disorders you have. They’re very, very different disorders. Impaired glucose tolerance really is the metabolic syndrome. These people have severe insulin resistance in muscle. They have a marked decrease in second phase insulin secretion. IFG, on the other hand, impaired fasting glucose, [is a] very different disorder. This is insulin resistance in liver and loss of first phase insulin secretion. It’s not really associated with a metabolic syndrome. You get an A1C and let’s say it’s 6.1. You know something’s wrong. But you need to delve further. Am I dealing with impaired fasting glucose or am I dealing with impaired glucose tolerance? Or combined? I believe that these disorders, because they have different pathophysiologies, should be treated differently. We have a very large study that’s going. Initially funded by the American Diabetes Association, now to look more carefully at what would be the best treatment for these two different types of disorders. Now, if you’re normal and you’re 5.0 or 5.4 you don’t have to worry about it. But if you’re in that grey zone then I think you need to know a little bit more and then of course if you have an A1C of 8, you know you have to do something in a more serious fashion.