Introduction

The ADA has been actively involved in the development and dissemination of diabetes care standards, guidelines, and related documents for over 20 years. ADA’s clinical practice recommendations are viewed as important resources for health care professionals who care for people with diabetes. ADA’s “Standards of Medical Care in Diabetes,” position statements, and scientific statements undergo a formal review process by ADA’s Professional Practice Committee (PPC) and the Executive Committee of the Board of Directors. The Standards and all ADA position statements, scientific statements, and consensus reports are available on the Association’s Web site at http://professional.diabetes.org/adastatements.

Standards of Care: ADA position statement that provides key clinical practice recommendations. The PPC performs an extensive literature search and updates the Standards annually based on the quality of new evidence.

A position statement is an official ADA point of view or belief that contains clinical or research recommendations. Position statements are issued on scientific or medical issues related to diabetes. They are published in ADA journals and other scientific/medical publications. ADA position statements are typically based on a systematic review or other review of published literature. Position statements undergo a formal review process. They are updated annually or as needed.

A scientific statement is an official ADA point of view or belief that may or may not contain clinical or research recommendations. Scientific statements contain scholarly synopsis of a topic related to diabetes. Workgroup reports fall into this category. Scientific statements are published in the ADA journals and other scientific/medical publications, as appropriate. Scientific statements also undergo a formal review process.

A consensus report contains a comprehensive examination by an expert panel (i.e., consensus panel) of a scientific or medical issue related to diabetes. A consensus report is not an ADA position and represents expert opinion only. The category may also include task force and expert committee reports. The need for a consensus report arises when clinicians or scientists desire guidance on a subject for which the evidence is contradictory or incomplete. A consensus report is typically developed immediately following a consensus conference where the controversial issue is extensively discussed. The report represents the panel’s collective analysis, evaluation, and opinion at that point in time based in part on the conference proceedings. A consensus report does not undergo a formal ADA review process.

Since the ADA first began publishing practice guidelines, there has been considerable evolution in the evaluation of scientific evidence and in the development of evidence-based guidelines. In 2002, we developed a classification system to grade the quality of scientific evidence supporting ADA recommendations for all new and revised ADA position statements. A recent analysis of the evidence cited in the Standards of Care found steady improvement in quality over the past 10 years, with last year’s Standards for the first time having the majority of bulleted recommendations supported by A- or B-level evidence (4). A grading system (Table 1) developed by ADA and modeled after existing methods was used to clarify and codify the evidence that forms the basis for the recommendations.

ADA recommendations are assigned ratings of A, B, or C, depending on the quality of evidence. Expert opinion E is a separate category for recommendations in which there is no evidence from clinical trials, in which clinical trials may be impractical, or in which there is conflicting evidence. Recommendations with an A rating are based on large well-designed clinical trials or well-done meta-analyses. Generally, these recommendations have the best chance of improving outcomes when applied to the population to which they are appropriate. Recommendations with lower levels of evidence may be equally important but are not as well supported.

Of course, evidence is only one component of clinical decision making. Clinicians care for patients, not populations; guidelines must always be interpreted with the individual patient in mind. Individual circumstances, such as comorbid and coexisting diseases, age, education, disability, and, above all, patients’ values and preferences, must be considered and may lead to different treatment targets and strategies. Also, conventional evidence hierarchies, such as the one adapted by the ADA, may miss nuances important in diabetes care. For example, although there is excellent evidence from clinical trials supporting the importance of achieving multiple risk factor control, the optimal way to achieve this result is less clear. It is difficult to assess each component of such a complex intervention.