Dr Kimberly Simmons and Dr Teresa Quattrin examine the diagnostic process and importance of screening for type 1 diabetes.
Robert Busch, MD: Dr Simmons, how are patients tested for type 1 diabetes? Dr Robin Goland mentioned stage III, when they have clinical diabetes. How are they tested for this? What are the standard tests that you might do?
Kimberly Simmons, MD, MPH/MSPH: Dr Goland talked about being able to intercede earlier. To do that, we can’t use the tests that we’ve been using all these years. In the office, if the pediatrician is concerned, most of the time they’re checking the urine for glucose or ketones or giving a random blood glucose if they have that available. If it’s not an urgent situation, often we’ll send a hemoglobin A1C [glycated hemoglobin], but we know from the American Diabetes Association that the standard diagnostic criteria are a little different from that. To diagnose, you must have elevation of a fasting glucose, an elevation on a 2-hour oral glucose tolerance test, an elevated hemoglobin A1C, or a random glucose that’s elevated with symptoms. Classically, those are the ways we would diagnose stage III, or type 1 diabetes. Most people are diagnosed at stage III because it’s a silent disease, until the end, when the beta cells are under an intense amount of stress.
What’s exciting is that there’s a test that we can do earlier in that disease process, while the disease is still clinically silent, that measures IDA autoantibodies, or type 1 diabetes–associated antibodies. There are 4 major biochemical antibodies: GAD, IA-2, insulin, and zinc transporter 8. What’s great is that they’re all available commercially. What’s hard is that the antibodies that have been used historically to develop all the data on risk of progression are the same methodology we might get in clinical practice. There’s a lot to learn about how to interpret those, but they’re widely available, and there are research studies widely available for people to have those antibodies measured.
Robert Busch, MD: Dr Quattrin, which patients do you screen for type 1 diabetes? Whom would you choose to screen? You’re not going to screen every patient. The incidence of type 1 is about 1 in 400 children. You’re certainly not going to screen 400 people, so whom would you home in on?
Teresa Quattrin, MD: There are data that show that the incidence is increasing. There are reports of a higher incidence than 1 in 400. For many years, there has been an effort supported by NIH [National Institutes of Health], and many other organizations, called TrialNet. We’ve been screening actively in many diabetes centers around the country for people who are deemed to be at high risk because they already have a relative with type 1 diabetes. Especially now that there’s an option to intervene, they should absolutely be tested. They can be tested as part of an effort that’s supported by the National Institutes of Health, or they can be tested commercially for the presence of these antibodies.
Additionally, TrialNet provides kits that can be sent to the family. As we talk about these topics, we have to realize that not all the patients have access to diabetes centers with a team of people. Therefore, it’s important that we also put in perspective the situation of patients who travel hundreds of miles to get there, and to make this available. Certainly, we screen first-degree relatives, but we also need to talk with pediatricians to come up with strategies. Even when a patient has a random elevated blood sugar but not be what we define as stage III—a stage where insulin therapy is needed—that patient should be screened with antibodies.
Our hope as pediatric endocrinologists and endocrinologists is that there might be an investment in the future to do a population screen. Most patients with type 1 diabetes—unfortunately, we see them in diabetes ketoacidosis—are in families without a person who has previously been diagnosed. There’s a way, but who are you going to be screening, and what’s the yield and cost benefit? This is a whole area in evolution. With a genetic predisposition and a genetic risk score, the yield could be increased.
The other issue—addressed by some of the papers and manuscripts in the field—is what age you’re going to do it. There isn’t a total agreement, but I hope to talk to our colleagues who are in the trenches—not only pediatricians, because most kids don’t have access to pediatricians—to share that this is something that can be screened for. If patients are at high risk and in limbo, that’s when blood sugars are abnormal. They have antibodies, and they may benefit from the therapy that has been approved.
Robert Busch, MD: What about patients who have other autoimmune diseases? As endocrinologists, we see Hashimoto disease, Addison disease, probably juvenile rheumatoid arthritis, and other autoimmune diseases, like celiac. Would you recommend screening those patients for the antibodies?
Teresa Quattrin, MD: Autoimmune parotitis is probably the most common autoimmune disease. Addison disease is more rare, and juvenile rheumatoid arthritis and rheumatoid arthritis are rarer. At a minimum, with diseases like juvenile rheumatoid arthritis and permutations of that, Addison disease, celiac and other autoimmune diseases, even psoriasis, the cost benefit is very high. Testing everybody with positive autoimmune antibodies may be a jump, but this is polyglandular failure, and the association of this constellation of symptoms is known. If there’s a familial disposition or the individual has other autoimmune diseases, then these individuals should be screened. I don’t know if I’d say that everybody who has positive antimicrosomal antibodies and parotitis should be screened more often than the general population. There’s the association, and even in type 1 diabetes, the most frequent second autoimmune disease is parotitis. In fact, we screen routinely for it.
Transcript Edited for Clarity