The Cost of Preventing Diabetes

What do we know and what do we need to know?

The landmark Diabetes Prevention Program (DPP) demonstrated that we can prevent diabetes (1). The DPP study in this issue of Diabetes Care (2) presents the costs of that intervention. The challenge is how to implement those findings in real-world clinical practice settings. I will first provide a framework for thinking about a cost study and then comment more specifically on the findings.

Randomized clinical trials (RCTs) answer the first important question—is an intervention efficacious? That is, can it work? RCTs are carefully structured to optimize the opportunity to demonstrate that an intervention can work; hence, they are conducted in relatively idealized environments. Patients are carefully identified, not only for their clinical characteristics, but also because of their willingness to participate as subjects. Institutions with strong research and clinical support environments are selected to ensure that interventions are delivered as optimally as possible to enhance the likelihood that any real effect will indeed be found. If the trial demonstrates efficacy, we have proof of concept. Yet, we know that simply showing that there is an efficacious strategy is insufficient. Translating those findings into routine practice is a critical and daunting challenge. Only 25% of hypertensive patients have their blood pressure controlled despite over a quarter of a century of concerted effort. Thus, showing that interventions can work is simply not enough.

The questions we really want answered concern not the efficacy of an intervention, but its effectiveness—how well does intervention work in practice? What is the balance between its benefits and harms? These issues require an understanding of the barriers to implementation and the development of appropriate systems and incentives to ensure delivery of and adherence to regimens on the part of providers and patients.

One of …