Screening and early detection of hyperglycemia are among the cornerstones in the recent Standards of Medical Care in Diabetes—2017 published by the American Diabetes Association (ADA) (1), despite the debate as to their overall benefits (2,3). In fact, this year new tools have been added to the bag: an “ADA risk test” (4) to screen for intermediate hyperglycemia (designated “prediabetes” by the ADA) and type 2 diabetes (T2D). If intermediate hyperglycemia is identified, then at least annual monitoring for the development of T2D is recommended. The risk evaluation is based on an online questionnaire in which a person’s risk is calculated on the basis of age, sex, family history of T2D, activity level, and weight.
Unfortunately, this strategy overestimates the risk and leads to unnecessary worries and use of medical resources (2,3). The implementation of the heterogeneous ADA criteria for prediabetes creates an epidemic with immense impact on health care systems. Based on ADA-defined prediabetes, which encompasses people with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or borderline elevated HbA1c, half of Chinese adults (∼500 million people) and one-third of the U.S. and U.K. populations have prediabetes—an enormous number of quite different people in terms of pathophysiology (hyperglycemia on three different scales) and T2D risk (large spectrum from low to higher risk).
According to the updated statement from the ADA, people should not only be advised to change lifestyle but should be “referred to an intensive behavioral lifestyle intervention program” based on the Diabetes Prevention Program (DPP) (5). Applying the intervention from the DPP study to the whole spectrum of people with intermediate hyperglycemia might not be desirable. The DPP study was conducted in overweight or obese people with both IGT and elevated fasting glucose. As people with IGT are in the higher spectrum of risk of progressing to T2D, the expectations of such a lifestyle program are likely exaggerated. Moreover, the data from the DPP study were not convincing (6,7). For example, the DPP study showed a relative risk reduction of 40–60% in overweight people with IGT, but follow-up analyses indicated that lifestyle interventions only delayed onset of T2D rather than preventing it. Also, in 10 years only 50% of people with IGT progress to T2D. The benefit of intensive lifestyle intervention for the rest of the population, i.e., those with IFG or borderline elevated HbA1c (the majority of people with intermediate hyperglycemia), is not clear (2).
In addition to these initiatives, an extra indication to initiate metformin has now been added for people with rising HbA1c despite lifestyle intervention (5). Such expansion of the ADA’s recommendation of metformin for “high-risk” people (BMI ≥35 kg/m2, age <60 years, women with prior gestational diabetes mellitus) is premature because metformin at best delays T2D a few years and shows no effect on complications (6,7). Again, data on people with IFG and moderately elevated HbA1c are lacking.
Clearly, initiatives toward using glucose-lowering drugs to decrease the progression from intermediate hyperglycemia to T2D seem unceasing, and more candidates are therefore likely to follow in the near future. However, persuasive evidence of long-term benefit is still lacking, especially for the millions of lower-risk people who are at risk of disease labeling and overtreatment. We fear that ADA’s glycocentric approach will lead to the acceptance of more glucose-lowering drugs to combat prediabetes. Instead, we should try to avoid premature diabetes treatment and demand an evidence-based approach to the prevention of T2D with meticulously performed meta-analyses that focus on patient-relevant outcomes, not just glycemia.
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Duality of Interest. No potential conflicts of interest relevant to this article were reported.
