The Existential Question of Prediabetes

Gregory A. Nichols, PhD


September 24, 2014

In This Article

The Epidemic of Pre-diabetes: The Medicine and the Politics

Yudkin JS, Montori VM
BMJ. 2014:349:g4485

What Is Prediabetes, and What Should Be Done About It?

As part of a series in the British Medical Journal on overdiagnosis, which looked at the risks and harms to patients of expanding disease definitions, Yudkin and Montori analyzed the concept of prediabetes. They began their analysis by reminding the reader that prediabetes is a heterogeneous concept.

The original category of intermediate hyperglycemia was termed "impaired glucose tolerance" and was based on the oral glucose tolerance test. Only since 1997 was an intermediate category of "impaired fasting glucose" created, with revision in 2003 to expand the range of qualifying values. Because A1c was not used for diagnostic testing until 2010, it is only recently that a nameless intermediate category based on A1c was designated. Unfortunately, the overlap of these three definitions is far from perfect, so the starting point for the discussion is already confused.

With that in mind, Yudkin and Montori reviewed the evidence, succinctly summarizing the case against considering elevated but subdiagnostic levels of glycemia—a disease unto itself that requires intervention. The authors stipulated that the value of a diagnosis of prediabetes would be that it "can provide benefit by precisely identifying those who will develop diabetes, allowing for effective interventions targeting both the disease and its complications." They then examined several questions to determine whether the evidence satisfies this stipulated value.

The Limited Value of Prediabetes

A key question examined by the authors was whether a diagnosis of prediabetes guarantees a future diagnosis of diabetes itself. Regardless of how prediabetes is defined, the answer is "no"—less than one half of all such people develop diabetes within 10 years.

Another important question is whether treatment of prediabetes can prevent diabetes onset. Clinical trials from around the world have demonstrated that diabetes risk among high-risk individuals can indeed be reduced, but Yudkin and Montori argue that diabetes onset was merely delayed by 2-4 years, at high cost and only among a subset of the intervention groups.

The following quote summarizes their position: "The US Diabetes Prevention Program results imply that you can give an at-risk person with pre-diabetes a 100% chance of using metformin with the goal of reducing by 31% their risk of developing a condition that might require them to use metformin." Yudkin and Montori conclude that it is critically important to address the epidemic of obesity and diabetes. However, they assert that available resources should be used to change the root causes of the epidemic rather than to medicalize otherwise healthy patients with prediabetes.



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