The End of Diabetes: The Eat to Live Plan to Prevent and Reverse Diabetes

Scotland has become the world’s first country to begin routine testing of C-peptide levels in patients with type 1 diabetes. The nation hopes to identify patients that have retained robust natural insulin production and who therefore may be able to amend their remedy regimens – and possibly even become aware of that they don’t have type 1 diabetes at all.

Misdiagnosis is a real problem in the diabetes community. As many as 38 percent of older adults that develop type 1 diabetes are misdiagnosed with type 2, for example, but misdiagnoses can happen in the opposite direction as well, and some patients won’t find out the truth for years. Meanwhile, those with less common forms of diabetes, such as latent autoimmune diabetes in adults (LADA) and maturity-onset diabetes of the young (MODY), may have an even more difficult time identifying the nature of their conditions.

Routine C-peptide testing could aid clear up some of the confusion. C-peptide is a substance that is created as a byproduct of natural insulin production. Measuring C-peptide is the easiest way doctors have to assess the amount of natural insulin in a patient’s bloodstream; the insulin you buy at the pharmacy and inject doesn’t contain any C-peptide at all.

Professor Mark Strachan of the Edinburgh Center for Endocrinology and Diabetes, who helped shepherd the new program, said in a press release:

“C-peptide helps diabetes specialists make a more accurate analysis of the cause of diabetes, and that means we can get people on the most appropriate treatment. In some instances, C-peptide testing allowed people to stop extremely long-standing insulin therapy; this can be life-transforming.”

The foundation for the program was a trial run by Dr. Strachan and his colleagues; the results were published in November 2020 in the journal Diabetic Medicine. At a single Scottish medical center, a total of 859 patients, all of whom had been diagnosed with type 1 diabetes at least 3 years previously, submitted to C-peptide testing.

Of those 859 patients, 114 (13.2%) had C-peptide over 200 pmol/L, indicating at least “intermediate” insulin secretion, above the usual expectations for patients with long-standing type 1 diabetes. Those patients then received further testing to determine why they were still producing so much insulin. Eventually, about half were found to have a different type of diabetes altogether, either type 2 or monogenic diabetes, a rare form of diabetes that can be notoriously difficult to identify and diagnose.

In total:

• 114 (13.2%) were still producing intermediate or substantial amounts of insulin
• 44 (5.1%) were reclassified to type 2 diabetes
• 14 (1.6%) were reclassified to monogenic diabetes

Of the above, 13 (1.5%) were advised to discontinue insulin, and an additional 16 (1.9%) enjoyed improved blood sugars after changing treatment strategies.

And, importantly for insurers and health authorities in other countries, the testing program was found to be very cost-effective. Optimizing the therapies of a minority of misdiagnosed patients more than paid for the administration of a routine blood examination to the entire group, not to mention the likely long-term health benefits for those that received an improved diagnosis.

What about the dozens of patients with natural insulin production who were not re-diagnosed? Some patients must have learned that they had more beta cell activity than they had previously suspected.

While type 1 diabetes is usually associated with a complete cessation of insulin production, the truth is somewhat messier. Many patients enjoy the so-called “honeymoon” phase after diagnosis, a period of partial remission during which the insulin-producing pancreatic beta cells are seemingly reinvigorated. Not every patient experiences a honeymoon period, but for some it can last years. In some lucky patients, a low level of beta cell function may persist even longer. In a study of Joslin gold medalists, some patients were found to have measurable natural insulin production even 50 years after diagnosis with type 1.

There’s no telling if or when C-peptide testing may become routine in other parts of the world. But the story serves as a useful reminder of the high frequency of misdiagnoses. We know that many members of our community have had to push for more testing before finally landing on an accurate diagnosis. If you suspect that your own condition has been misdiagnosed, consider sharing your thoughts with your doctor or endocrinologist. They might even start by asking you to take a blood examination for C-peptides.

Diabetes Daily

The End of Diabetes: The Eat to Live Plan to Prevent and Reverse Diabetes