• American Diabetes Association (ADA). Standards of medical care in diabetes. II. Testing for pre-diabetes and diabetes in asymptomatic patients. Diabetes Care 2008 Jan;31(Suppl 1):S13-4.

This is the current release of the guideline.

This guideline updates a previous version: American Diabetes Association (ADA). Standards of medical care in diabetes. II. Screening for diabetes. Diabetes Care 2007 Jan;30(Suppl 1):S5-7.

• Type 2 diabetes mellitus
• Pre-diabetes (impaired fasting glucose [IFG] or impaired glucose tolerance [IGT])

Evaluation
Risk Assessment
Screening

Endocrinology
Family Practice
Internal Medicine
Pediatrics
Preventive Medicine

Advanced Practice Nurses
Allied Health Personnel
Nurses
Physician Assistants
Physicians
Public Health Departments

• To make recommendations regarding testing for pre-diabetes and type 2 diabetes in asymptomatic patients
• To provide clinicians, patients, researchers, payers, and other interested individuals with the components of diabetes care, treatment goals, and tools to evaluate the quality of care

• Asymptomatic adults at risk of developing type 2 diabetes mellitus (i.e., individuals with body mass index [BMI] >25 kg/m² and additional risk factors)
• Asymptomatic adults >45 years of age without risk factors
• Children at risk of developing diabetes mellitus (i.e., those with a BMI >85^th percentile for age and sex, weight for height >85^th percentile, or weight >120% of ideal for height, plus two additional risk factors)

1. Assessment of risk factors for type 2 diabetes
2. Testing for pre-diabetes and type 2 diabetes with fasting plasma glucose [FPG] or 2-hour oral glucose tolerance test [OGTT]
3. Repeat testing if needed
4. Identifying and treating other cardiovascular (CVD) risk factors if appropriate

Note: Guideline developers considered but did not recommend screening for type 1 diabetes in asymptomatic patients

Effectiveness of screening tests

Searches of Electronic Databases

Not stated

Not stated

Weighting According to a Rating Scheme (Scheme Given)

American Diabetes Association's Evidence Grading System for Clinical Practice Recommendations

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 non-experimental evidence (i.e., "all or none" rule developed by the Center 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

*Either all patients died before therapy and at least some survived with therapy, or some patients died without therapy and none died with therapy. Example: use of insulin in the treatment of diabetic ketoacidosis.

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 with 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

Systematic Review

Not stated

Expert Consensus

Not stated

Recommendations have been assigned ratings of A, B or C, depending on the quality of evidence (see "Rating Scheme for the Strength of the Evidence"). 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.

A formal cost analysis was not performed and published cost analyses were not reviewed.

Internal Peer Review

The recommendations were reviewed and approved in October 2007 by the Professional Practice Committee and, subsequently, by the Executive Committee of the Board of Directors.

The evidence grading system (A through C, E) is defined at the end of the "Major Recommendations" field.

Testing for Pre-diabetes and Diabetes in Asymptomatic Patients

• Testing to detect pre-diabetes and type 2 diabetes in asymptomatic people should be considered in adults who are overweight or obese (body mass index [BMI] >25 kg/m²) and who have one or more additional risk factors for diabetes. In those without these risk factors, testing should begin at age 45. (B)
• If tests are normal, repeat testing should be carried out at least at 3-year intervals. (E)
• To test for pre-diabetes or diabetes, either a fasting plasma glucose (FPG) test or a 2-h oral glucose tolerance test (OGTT) (75-g glucose load) or both are appropriate. (B)
• An oral glucose tolerance test may be considered in patients with impaired fasting glucose (IFG) to better define the risk of diabetes. (E)
• In those identified with pre-diabetes, identify and, if appropriate, treat other cardiovascular disease (CVD) risk factors. (B)

Criteria for Testing for Pre-Diabetes and Diabetes in Asymptomatic Adult Individuals

*At-risk BMI may be lower in some ethnic groups.

Testing for Type 2 Diabetes in Asymptomatic Children

Definitions:

American Diabetes Association's Evidence Grading System for Clinical Practice Recommendations

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 non-experimental evidence (i.e., "all or none" rule developed by the Center 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

*Either all patients died before therapy and at least some survived with therapy, or some patients died without therapy and none died with therapy. Example: use of insulin in the treatment of diabetic ketoacidosis.

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 with 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

None provided

The type of supporting evidence is identified and graded for each recommendation (see the "Major Recommendations" field).

Screening of high-risk asymptomatic patients for diabetes and pre-diabetes may help to prevent the progression of pre-diabetes to diabetes and reduce the risk of complications of diabetes by early recognition and treatment.

Not stated

• Evidence is only one component of 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, patient's 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 American Diabetes Association 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.
• While individual preferences, comorbidities, and other patient factors may require modification of goals, targets that are desirable for most patients with diabetes are provided. These standards are not intended to preclude more extensive evaluation and management of the patient by other specialists as needed.

In recent years, numerous health care organizations, ranging from large health care systems such as the U.S. Veteran's Administration to small private practices have implemented strategies to improve diabetes care. Successful programs have published results showing improvement in process measures such as measurement of A1C, lipids, and blood pressure. Successful interventions have been focused at the level of health care professionals, delivery systems, and patients. Features of successful programs reported in the literature include:

• Improving health care professional education regarding the standards of care through formal and informal education programs.
• Delivery of diabetes self-management education (DSME), which has been shown to increase adherence to standard of care.
• Adoption of practice guidelines, with participation of health care professionals in the process. Guidelines should be readily accessible at the point of service, such as on patient charts, in examining rooms, in "wallet or pocket cards," on Personal Digital Assistants (PDAs), or on office computer systems. Guidelines should begin with a summary of their major recommendations instructing health care professionals what to do and how to do it.
• Use of checklists that mirror guidelines have been successful at improving adherence to standards of care.
• Systems changes, such as provision of automated reminders to health care professionals and patients, reporting of process and outcome data to providers, and especially identification of patients at risk because of failure to achieve target values or a lack of reported values.
• Quality improvement programs combining continuous quality improvement or other cycles of analysis and intervention with provider performance data.
• Practice changes, such as clustering of dedicated diabetes visits into specific times within a primary care practice schedule and/or visits with multiple health care professionals on a single day and group visits.
• Tracking systems either with an electronic medical record or patient registry have been helpful at increasing adherence to standards of care by prospectively identifying those requiring assessments and/or treatment modifications. They likely could have greater efficacy if they suggested specific therapeutic interventions to be considered for a particular patient at a particular point in time.
• A variety of non-automated systems, such as mailing reminders to patients, chart stickers, and flow sheets, have been useful to prompt both providers and patients.
• Availability of case or (preferably) care management services, usually by a nurse. Nurses, pharmacists, and other non-physician health care professionals using detailed algorithms working under the supervision of physicians and/or nurse education calls have also been helpful. Similarly dietitians using medical nutrition therapy (MNT) guidelines have been demonstrated to improve glycemic control.
• Availability and involvement of expert consultants, such as endocrinologists and diabetes educators.

Evidence suggests that these individual initiatives work best when provided as components of a multifactorial intervention. Therefore, it is difficult to assess the contribution of each component; however, it is clear that optimal diabetes management requires an organized, systematic approach and involvement of a coordinated team of health care professionals.

Staying Healthy

Effectiveness

• American Diabetes Association (ADA). Standards of medical care in diabetes. II. Testing for pre-diabetes and diabetes in asymptomatic patients. Diabetes Care 2008 Jan;31(Suppl 1):S13-4.

Not applicable: The guideline was not adapted from another source.

1998 (revised 2008 Jan)

American Diabetes Association - Professional Association

The American Diabetes Association (ADA) received an unrestricted educational grant from LifeScan, Inc., a Johnson and Johnson Company, to support publication of the 2008 Diabetes Care Supplement.

Professional Practice Committee

Committee Members: Irl Hirsch, MD, Chair; Martin Abrahamson, MD; Andrew Ahmann, MD; Lawrence Blonde, MD; Silvio Inzucchi, MD; Mary T. Korytkowski, MN, MD, MSN; Melinda Maryniuk, MEd, RD, CDE; Elizabeth Mayer-Davis, MS, PhD, RD; Janet H. Silverstein, MD; Robert Toto, MD

Not stated

This is the current release of the guideline.

This guideline updates a previous version: American Diabetes Association (ADA). Standards of medical care in diabetes. II. Screening for diabetes. Diabetes Care 2007 Jan;30(Suppl 1):S5-7.

None available

This summary was completed by ECRI on April 2, 2001. The information was verified by the guideline developer on August 24, 2001. This summary was updated by ECRI on March 14, 2002, July 29, 2003, March 23, 2004, July 1, 2005, and March 16, 2006, and April 24, 2007. This summary was updated most recently by ECRI Institute on March 31, 2008. The updated information was verified by the guideline developer on May 15, 2008.