Redefining diabetes: Lines blurring in diagnosis

More patients have characteristics of both type 1 and type 2 -- creating treatment challenges for physicians and puzzles for researchers.

By Victoria Stagg Elliott, AMNews staff. Dec. 5, 2005.

Mark E. Meijer, MD, a family physician in South Hill, Va., has noticed that, when it comes to his patients, the lines between type 1 and type 2 diabetes are increasingly blurry.

"The majority by far are easy to distinguish, but there are more and more patients who are ambiguous," said Dr. Meijer, the author of the book, Ten Steps to Control Diabetes.

For instance, one woman had been a type 1 diabetic her whole life, but she was also obese and had cholesterol levels as high as many of his patients with type 2. Another example: a man in his 30s who looked like a typical type 2 diabetic. But when Dr. Meijer had him fast as part of his assessment, he went rapidly into diabetic ketoacidosis -- a problem far more typical of those with type 1.

These are anecdotes, but they support the notion that doctors increasingly are faced with more complex diabetic patients, including those who don't fit neatly in the type 1 or type 2 box. Actually, they appear to have characteristics of both.

"We'd like to believe that type 1 diabetes and type 2 diabetes are very distinct, and that it's very clear when we see a patient which type of diabetes they have," said Nathaniel Clark, MD, national vice president for clinical affairs for the American Diabetes Assn. "In fact, that's not true."

Patients are showing up overweight and with evidence of insulin resistance, signals that seem to point toward a diagnosis of type 2. On testing, however, they appear to be positive for the antibodies that suggest type 1. Or they might present with diabetic ketoacidosis, a clear sign of the onset of type 1, only to come up negative on tests for antibodies. After a short period of time on insulin, many are able to maintain their health on the oral agents usually reserved for those with type 2.