Update of ADA's major position statement, "Standards of Medical Care in Diabetes". Introduction.

The American Diabetes Association (ADA) has been actively involved in the development and dissemination of diabetes care standards, guidelines, and related documents for many years. These statements are published in one or more of the Association's professional journals. This supplement contains the latest update of ADA's major position statement, “Standards of Medical Care in Diabetes,” which contains all of the Association's key recommendations. In addition, contained herein are selected position statements on certain topics not adequately covered in the “Standards.” ADA hopes that this is a convenient and important resource for all health care professionals who care for people with diabetes.

ADA Clinical Practice Recommendations consist of position statements that represent official ADA opinion as denoted by formal review and approval by the Professional Practice Committee and the Executive Committee of the Board of Directors. Consensus reports and systematic reviews are not official ADA recommendations; however, they are produced under the auspices of the Association by invited experts. These publications may be used by the Professional Practice Committee as source documents to update the “Standards.”

ADA has adopted the following definitions for its clinically related reports.

ADA position statement.

An official point of view or belief of the ADA. Position statements are issued on scientific or medical issues related to diabetes. They may be authored or unauthored and are published in ADA journals and other scientific/medical publications as appropriate. Position statements must be reviewed and approved by the Professional Practice Committee and, subsequently, by the Executive Committee of the Board of Directors. ADA position statements are typically based on a systematic review or other review of published literature. They are reviewed on an annual basis and updated as needed. A list of recent position statements is included on p. S100 of this supplement.

Systematic review.

A balanced review and analysis of the literature on a scientific or medical topic related to diabetes. Effective January 2010, technical reviews are replaced with systematic reviews, for which a priori search and inclusion/exclusion criteria are developed and published. The systematic review provides a scientific rationale for a position statement and undergoes critical peer review before submission to the Professional Practice Committee for approval. A list of past technical reviews is included on page S99 of this supplement.

Consensus report.

A comprehensive examination by a panel of experts (i.e., consensus panel) of a scientific or medical issue related to diabetes. Effective January 2010, consensus statements were renamed consensus reports. The category now also includes task force, workgroup, and expert committee reports. Consensus reports do not have the Association's name included in the title or subtitle and include a disclaimer in the introduction stating that any recommendations are not ADA position. A consensus report is typically developed immediately following a consensus conference at which presentations are made on the issue under review. The statement represents the panel's collective analysis, evaluation, and opinion at that point in time based in part on the conference proceedings. The need for a consensus report arises when clinicians or scientists desire guidance on a subject for which the evidence is contradictory or incomplete. Once written by the panel, a consensus report is not subject to subsequent review or approval and does not represent official Association opinion. A list of recent consensus reports is included on p. S102 of this supplement.

Professional Practice Committee.

The Association's Professional Practice Committee is responsible for reviewing ADA systematic reviews and position statements, as well as for overseeing revisions of the latter as needed. Appointment to the Professional Practice Committee is based on excellence in clinical practice and/or research. The committee comprises physicians, diabetes educators, registered dietitians, and others who have expertise in a range of areas, including adult and pediatric endocrinology, epidemiology, and public health, lipid research, hypertension, and preconception and pregnancy care. All members of the Professional Practice Committee are required to disclose potential conflicts of interest (listed on page S97).

Grading of scientific evidence.

There has been considerable evolution in the evaluation of scientific evidence and in the development of evidence-based guidelines since the ADA first began publishing practice guidelines. Accordingly, we developed a classification system to grade the quality of scientific evidence supporting ADA recommendations for all new and revised ADA position statements.

Recommendations are assigned ratings of A, B, or C, depending on the quality of evidence (Table 1). Expert opinion (E) is a separate category for recommendations in which there is as yet 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. The level of evidence supporting a given recommendation is noted either as a heading for a group of recommendations or in parentheses after a given recommendation.

Table 1

ADA evidence-grading system for clinical practice recommendations

Level of evidence	Description
A	Clear evidence from well-conducted, generalizable, randomized controlled trials that are adequately powered, including: · Evidence from a well-conducted multicenter trial · Evidence from a meta-analysis that incorporated quality ratings in the analysis
	Compelling nonexperimental evidence, i.e., the “all or none” rule developed by the Centre for Evidence-Based Medicine at Oxford
	Supportive evidence from well-conducted randomized controlled trials that are adequately powered, including: · Evidence from a well-conducted trial at one or more institutions · Evidence from a meta-analysis that incorporated quality ratings in the analysis
B	Supportive evidence from well-conducted cohort studies, including: · Evidence from a well-conducted prospective cohort study or registry · Evidence from a well-conducted meta-analysis of cohort studies
	Supportive evidence from a well-conducted case-control study
C	Supportive evidence from poorly controlled or uncontrolled studies, including: · Evidence from randomized clinical trials with one or more major or three or more minor methodological flaws that could invalidate the results · Evidence from observational studies with high potential for bias (such as case series with comparison to historical controls) · Evidence from case series or case reports
	Conflicting evidence with the weight of evidence supporting the recommendation
E	Expert consensus or clinical experience

Of course, evidence is only one component of clinical decision-making. Clinicians care for patients, not populations; guidelines must always be interpreted with the needs of the individual patient in mind. Individual circumstances, such as comorbid and coexisting diseases, age, education, disability, and, above all, patients' values and preferences, must also 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 some nuances that are important in diabetes care. For example, while there is excellent evidence from clinical trials supporting the importance of achieving glycemic control, the optimal way to achieve this result is less clear. It is difficult to assess each component of such a complex intervention.

ADA will continue to improve and update the Clinical Practice Recommendations to ensure that clinicians, health plans, and policymakers can continue to rely on them as the most authoritative and current guidelines for diabetes care. Our Clinical Practice Recommendations are also available on the Association's website at www.diabetes.org/diabetescare.