Controversies in prediabetes: do we have a diagnosis?

It is estimated that more than one-third of US adults exhibit intermediate glycemic control, termed "prediabetes" or "impaired glucose regulation," and many individuals with prediabetes or diabetes are unaware of their glycemic state. Prediabetes confers significant risks for developing type 2 diabetes mellitus (T2DM) and cardiovascular comorbidities. Early lifestyle intervention and pharmacotherapy have demonstrated success in preventing or delaying onset of T2DM. Thus, early screening and diagnosis of prediabetes, along with subsequent recommendations on preventative measures, are vital in preventing or delaying progression to T2DM. However, a consensus among organizations on the diagnostic criteria defining prediabetes has not been reached, complicating the screening and diagnostic process and resulting in varying subpopulations of patients diagnosed with prediabetes. In this article, the guidelines issued by several organizations are reviewed, as well as recent studies analyzing the predictive value of various diagnostic criteria for the progression to T2DM. Recent trials investigating the effects of lifestyle modification and/or pharmacotherapy on the prevention or delay of development of T2DM have suggested some complex outcomes that require further clarification, but offer some hope for the future. These results, and the varying guidelines for the diagnosis of prediabetes, suggest a need for informed scientific debate on diagnostic criteria and recommendations for preventive care of prediabetic states.