• Aarsand AK, Alter D, Frost SJ, Kaplanis B, Klovning A, Price CP, Sacks DB, Sandberg S, St. John A, Swaminathan R, Winter WE. Diagnosis and management of diabetes mellitus. In: Laboratory medicine practice guidelines: evidence-based practice for point-of-care testing. Washington (DC): National Academy of Clinical Biochemistry (NACB); 2006. p. 44-62. [196 references]

This is the current release of the guideline.

• Type 1 and 2 diabetes mellitus
• Gestational diabetes

Assessment of Therapeutic Effectiveness
Diagnosis
Management

Endocrinology
Family Practice
Internal Medicine
Obstetrics and Gynecology
Pediatrics

Advanced Practice Nurses
Allied Health Personnel
Clinical Laboratory Personnel
Health Care Providers
Hospitals
Nurses
Patients
Physician Assistants
Physicians
Public Health Departments

• To examine the application of evidence-based medicine (EBM) to the form of diagnostic testing known as point-of-care testing (POCT)

  Note: For the purpose of this document, POCT is defined as "clinical laboratory testing conducted close to the site of patient care, typically by clinical personnel whose primary training is not in the clinical laboratory sciences or by patients (self-testing). POCT refers to any testing performed outside of the traditional, core or central laboratory."

• To systematically review and synthesize the available evidence on the effectiveness of POCT, with specific focus on outcomes in the areas of:
  1. Patient/health
  2. Operational/management
  3. Economic benefit
• To review literature to determine whether guidelines can be developed to support point-of-care testing (POCT) in the diagnosis and management of diabetes

• Patients with type 1 and 2 diabetes mellitus
• Pregnant women with gestational diabetes

Point of care glycosylated hemoglobin (HbA1c) testing in both the primary and secondary care setting

Note: The following tests were considered but not recommended: self-monitoring blood glucose (SMBG) in primary care, point-of-care (POC) blood glucose in gestational diabetes, fructosamine, blood ketones, urine albumin screening in primary and secondary care.

• Patient outcomes (e.g., glycosylated hemoglobin levels, glycemic control, changes in management)
• Clinical utility of tests
• Patient and clinician satisfaction
• Economic benefit

Hand-searches of Published Literature (Primary Sources)
Searches of Electronic Databases

For a specific clinical use, pertinent clinical questions were formulated and key search terms were ascertained for the literature search. Searches were conducted on MEDLINE or PubMed and were supplemented with the use of the National Guideline Clearinghouse, the Cochrane Group, or evidence-based medicine (EBM) reviews. Additionally, authors' personal article collections were used. Acceptable citations were limited to peer-reviewed articles with abstracts, those published in English, and those involving human subjects.

To be included in the full systematic review of the clinical question, articles selected for full text review were examined for at least 1 relevant outcomes measurement.

See the original guideline document and Appendix B (see the "Availability of Companion Documents" field) for specific details of the literature searches.

Not stated

Weighting According to a Rating Scheme (Scheme Given)

Levels of Evidence

1. Evidence includes consistent results from well-designed, well-conducted studies in representative populations.
2. Evidence is sufficient to determine effects, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies; generalizability to routine practice; or indirect nature of the evidence.
3. Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information.

Review of Published Meta-Analyses
Systematic Review with Evidence Tables

Abstracts identified by the literature searches were reviewed by 2 individuals to determine initial eligibility or ineligibility for full-text review, using Form 1 (Appendix A - see the "Availability of Companion Documents" field). If there was not consensus, then a third individual reviewed the abstract(s). To be included in the full systematic review of the clinical question, articles selected for full text review were examined for at least 1 relevant outcomes measurement. The systematic review consisted of creating evidence tables using Form 2 (Appendix A - see the "Availability of Companion Documents" field) that incorporated the following characteristics:

1. Study design—Prospective or retrospective, randomized, and controlled, patient inclusion/exclusion criteria, blinding, number of subjects, etc.
2. Appropriateness of controls
3. Potential for bias (consecutive or nonconsecutive enrollment)
4. Depth of method description—full-length report or technical brief
5. Clinical application—screening, diagnosis, management
6. Specific key outcomes and how they were measured
7. Conclusions are logically supported

For the assessment of study quality, the general approach to grading evidence developed by the US Preventive Services Task Force was applied (see the "Rating Scheme for the Strength of the Evidence" field). Once that was done, an assessment of study quality was performed, looking at the individual and aggregate data at 3 different levels using Forms 3 and 4 (Appendix A - see the "Availability of Companion Documents" field). At the first level, the individual study design was evaluated, as well as internal and external validity. Internal validity is the degree to which the study provides valid evidence for the populations and setting in which it was conducted. External validity is the extent to which the evidence is relevant and can be generalized to populations and conditions of other patient populations and point-of-care testing (POCT) settings.

The synthesis of the volume of literature constitutes the second level, Form 5 (Appendix A - see the "Availability of Companion Documents" field). Aggregate internal and external validity was evaluated, as well as the coherence/consistency of the body of data. How well does the evidence fit together in an understandable model of how POCT leads to improved clinical outcome? Ultimately, the weight of the evidence about the linkage of POCT to outcomes is determined by assessing the degree to which the various bodies of evidence (linkages) "fit" together. To what degree is the testing in the same population and condition in the various linkages? Is the evidence that connects POCT to outcome direct or indirect? Evidence is direct when a single linkage exists but is indirect when multiple linkages are required to reach the same conclusion.

Expert Consensus

The field of point-of-care testing (POCT), diagnostic testing conducted close to the site of patient care, was divided into disease- and test-specific focus areas. Groups of expert physicians, laboratorians, and diagnostic manufacturers in each focus area were assembled to conduct systematic reviews of the scientific literature and prepare guidelines based on the strength of scientific evidence linking the use of POCT to patient outcome.

Final guidelines were made according to Agency for Healthcare Research and Quality (AHRQ) classification (see the Rating Scheme for the Strength of the Recommendations field). The guidelines are evidence based and require scientific evidence that the recipients of POCT experience better health outcomes than those who did not and that the benefits are large enough to outweigh the risks. Consensus documents are not research evidence and represent guidelines for clinical practice, and inclusion of consensus documents was based on the linkages to outcomes, the reputation of the peer organization, and the consensus process used to develop the document. Health outcomes, e.g., benefit/harm, are the most significant outcomes in weighing the evidence and drafting guidelines.

Strength of Recommendations

A - The National Academy of Clinical Biochemistry (NACB) strongly recommends adoption; there is good evidence that it improves important health outcomes and concludes that benefits substantially outweigh harms.

B - The NACB recommends adoption; there is at least fair evidence that it improves important health outcomes and concludes that benefits outweigh harms.

C - The NACB recommends against adoption; there is evidence that it is ineffective or that harms outweigh benefits.

I - The NACB concludes that the evidence is insufficient to make recommendations; evidence that it is effective is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.

Self-Monitoring of Blood Glucose

One study dealing with cost-effectiveness of self-monitoring blood glucose (SMBG) in type I diabetes mellitus (DM) found that urine monitoring was cost-effective, whereas blood monitoring was not. However, these findings are difficult to transfer to other settings.

A second study found that bedside glucose testing is not inherently more expensive than centralized laboratory measurements, but implementation on inefficient care units with low use can add substantially to the cost. Much of the excess cost of the bedside method can be attributed to the high costs of quality control and quality assurance, training, and documentation.

A third study compared the operating cost of point-of care (POC) testing for glucose and an electrolyte/glucose/blood urea nitrogen (BUN) chemistry panel with the cost of central laboratory stat testing in a 204-bed community hospital. In the scenarios studied, POC testing costs exceed central laboratory stat costs from 1.1 to 4.6 times. The more the POC testing is used, the greater the excess costs compared to the central laboratory. Cost analysis demonstrates that the investment in acquiring automated transport and data management systems for the hospital was far less expensive than POC testing for an individual stat test and on an annual cost basis.

Glycosylated Hemoglobin (HbA1c) Testing

Economic assessments of the use of diagnostic tests are rare, and invariably the economic data are poor. In the field of laboratory medicine, the main emphasis has been on the cost per test, and there has been little attention given to the wider benefits of testing. The situation is no different in the case of point of care testing (POCT) for HbA1c. One group of researchers looked at the use of a wide range of healthcare resources, including outpatient visits and contact time with staff, and found that POCT did not lead to any significant change in the use of resources. Another group of researchers found that the costs of POCT for HbA1c were higher than the laboratory provided service; when a laboratory analyzer was taken down to the clinic and run by a technologist, the costs were marginally higher that that of the conventional laboratory service. However, from an analysis of the retrospective cohort study, they found that there was a reduction in clinic visits using the POCT modality (from 2.28 visits per year per patient to a figure of 1.81), which helped to ameliorate the increased cost of testing. The prospective trial of POCT was only undertaken for a 3-month period, and a longer study is needed to provide more robust economic data.

Economic modeling from the Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) studies shows an economic benefit from intensive glycemic control, with a long-term benefit, albeit at increased short-term cost. An economic analysis of diabetes care in the Kaiser Permanente healthcare system has shown that improved glycemic control does lead to an improved economic outcome when judged in terms of the long-term benefit, primarily due to the reduction in hospital costs associated with emergency admissions, increased periods of hospital stay, and more clinic visits. It is only by modeling the use of POCT into this environment that the true economic assessment of POCT can be made.

Refer to the original guideline document for more information on cost analysis.

Peer Review

The guidelines were presented in open forum at the American Association for Clinical Chemistry (AACC) Annual Meeting (Los Angeles, CA, USA) in July 2004. Portions of these guidelines were also presented at several meetings between 2003 and 2005. Participants at each meeting had the ability to discuss the merits of the guidelines and submit comments to the National Academy of Clinical Biochemistry (NACB) Web site for formal response by the NACB during the open comment period from January 2004 through October 2005.

These recommendations are compared with those given by the World Health Organization, the American Diabetes Association (ADA), the National Academy of Clinical Biochemistry (NACB), and the National Institute for Clinical Excellence (NICE).

None provided

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

It is hoped that these guidelines will be useful for those implementing new testing, as well as those reviewing the basis of current practice. These guidelines should help sort fact from conjecture when testing is applied to different patient populations and establish proven applications from off-label and alternative uses of point-of-care testing (POCT). These guidelines will also be useful in defining mechanisms for optimizing patient outcome and identify areas lacking in the current literature that are needed for future research.

Not stated

• The material in this monograph represents the opinions of the editors and does not represent the official position of the National Academy of Clinical Biochemistry or any of the cosponsoring organizations.
• Point-of-care testing (POCT) is an expanding delivery option because of increased pressure for faster results. However, POCT should not be used as a core laboratory replacement in all patient populations without consideration of the test limitations and evaluation of the effect of a faster result on patient care.
• In drawing together the conclusions from this review of the evidence on POCT in the diagnosis and management of diabetes mellitus, the reader is referred to an observation that "absence of evidence of effect does not constitute evidence of absence of effect". It has been acknowledged on many occasions in the literature that generating data on the outcomes from the use of "diagnostic tests" with robust study design can be extremely challenging, particularly true in the case of a complex condition such as diabetes mellitus, where, in the management of the condition, the test and the intervention are intimately linked and it is the combined use of test and intervention that yields an improved health outcome. In addition, it is also recognized that it can be difficult to design studies that minimize the risk of bias in the study results, as with the use of a randomized controlled study (RCT). Thus, as has been suggested in earlier systematic reviews of aspects of diabetes care, it may be necessary to look at other types of study design, e.g., observational studies. This effectively looks at a package of care and measures taken to involve patients in managing their own healthcare. In this respect, it is worthy of note that many of the current guidelines on the management of diabetes mellitus indicate the use of "diagnostic tests" as part of an "integrated package of care" and "taking account of patient's needs and expectations." Further research is needed on the use of POCT as part of an integrated package of care in the management of diabetes mellitus.

An implementation strategy was not provided.

Living with Illness

Effectiveness
Patient-centeredness

• Aarsand AK, Alter D, Frost SJ, Kaplanis B, Klovning A, Price CP, Sacks DB, Sandberg S, St. John A, Swaminathan R, Winter WE. Diagnosis and management of diabetes mellitus. In: Laboratory medicine practice guidelines: evidence-based practice for point-of-care testing. Washington (DC): National Academy of Clinical Biochemistry (NACB); 2006. p. 44-62. [196 references]

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

2006

National Academy of Clinical Biochemistry - Professional Association

National Academy of Clinical Biochemistry

Guidelines Committee

Committee Members: Robert H. Christenson, Ph.D., FACB, University of Maryland School of Medicine, Baltimore, Maryland, USA; William Clarke, Ph.D., Johns Hopkins Medical Institutions, Baltimore, Maryland, USA; Ann Gronowski, Ph.D., FACB, Washington University, St. Louis, Missouri, USA; Catherine A. Hammett-Stabler, Ph.D., FACB, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA; Ellis Jacobs, Ph.D., FACB, New York State Department of Health, Albany, New York, USA; Steve Kazmierczak, Ph.D., FACB, Oregon Health and Science University, Portland, Oregon, USA; Kent Lewandrowski, M.D., Massachusetts General Hospital, Boston, Massachusetts, USA; Christopher Price, Ph.D., FACB, University of Oxford, Oxford, UK; David Sacks, M.D., FACB, Brigham and Women's Hospital, Boston, Massachusetts, USA; Robert Sautter, Ph.D., Carolinas Medical Center, Charlotte, North Carolina, USA; Greg Shipp, M.D., Nanosphere, Northbrook, Illinois, USA; Lori Sokoll, Ph.D., FACB, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA; Ian Watson, Ph.D., FACB, University Hospital Aintree, Liverpool, UK; William Winter, M.D., FACB, University of Florida, Gainesville, Florida, USA; Marcia L. Zucker, Ph.D., FACB, International Technidyne Corporation (ITC), Edison, New Jersey, USA

Not stated

This is the current release of the guideline.

None available

This NGC summary was completed by ECRI Institute on August 10, 2007. The information was verified by the guideline developer on September 24, 2007.

National Academy of Clinical Biochemistry's (NACB) terms for reproduction of guidelines are posted with each set of guidelines.