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Techniques for Locating Evidence-Based Practice Resources

What Is Evidence-Based Medicine?

Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.

Sacket DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS. (1996)
Evidence based medicine: what it is and what it isn't. BMJ 312: 71-2.

User Guides to Evidence-Based Practice, developed by McMaster University's Evidence-Based Medicine Informatics Project, are disseminated on the Internet by the Canadian Centres for Health Evidence.

Criticisms

Criticisms of evidence-based practice (EBP) have focused on four major issues:

  1. The belief that EBP focuses exclusively on the use of medical literature in making diagnostic and therapeutic decisions, to the exclusion of the clinical knowledge and skill of the health care practitioner (although this is not implicit in the definition of the term).
  2. A concern that if EBP relies too heavily on quantitative criteria, qualitative factors and specific patient information will be ignored.
  3. That EBP is, or will be, controlled by HMOs and used as a form of economic control rather than as a method of providing best patient care.
  4. That EBP is not new. Good practitioners have always looked at the literature.

A sampling of critical, peer-reviewed articles on the topic of evidence-based practice appearing in MEDLINE during the past year include:

Evidence-Based Practice Terminology

Types of Information for Evidence-Based Practice

Systematic Reviews and Meta-Analyses

Systematic reviews or overviews in clinical medicine were originally summaries of relevant randomized controlled trials (RCTs), performed in a systematic way so their results could be duplicated by other researchers. However, because there is a paucity of RCTs available in many clinical areas and almost none available in public health areas, systematic reviews employ the best external evidence available: RCTs when possible, and comparative studies or primary studies when no RCTs exist. Meta-analyses are systematic reviews which employ a quantitative method to summarize results.

The Cochrane Collaboration

Archie Cochrane, a British epidemiologist, wrote in 1979, "It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomized controlled trials." (Cochrane AL. Effectiveness and Efficiency. Random Reflections on Health Services. London: Nuffield Provincial Hospitals Trust, 1972. (Reprinted in 1989 in association with BMJ.) In response to Cochrane's call for critical summaries, the Cochrane Collaboration developed in 1992. Currently there are fifteen Cochrane Centers around the world.

The full text systematic reviews are the heart of the Cochrane Collaboration. Currently there are 1,081 complete reviews and 866 protocols (reviews in progress). Reviews are authored by volunteers from around the world, who work with the appropriate Collaborative Review Group. There are presently 50 collaborative review groups, covering such topics as back pain; depression, anxiety and neurosis; pregnancy and childbirth; stroke; and wounds.

The Cochrane Collaboration is not a "user friendly" database and searches can be confusing. The search screen is located at the top of the page, and searches may be done by MeSH headings or by keywords. MeSH is the National Library of Medicine's controlled vocabulary used for indexing articles in MEDLINE. The term "keywords" means you will find the terms appearing anywhere in the text. Because the database is full text, keyword searches may bring up reviews that are using the key word incidentally, and many false hits may result. When possible, use MeSH headings. If you're not sure if there is an appropriate MeSH heading, an index is provided.
Sample Search

Centre for Evidence-Based Nursing

The Centre for Evidence-Based Nursing, located at the University of York, United Kingdom, is a centre of expertise for the conduct and dissemination of systematic reviews. The Centre for Evidence-Based Nursing serves as the editorial base for the Cochrane Wounds Group. Nicky Cullom from the Centre participated in a systematic review of clinical practice guidelines in nursing and other health professions.

Thomas LH, McColl E, Cullom N, Rousseau N, Soutter J, Steen N. Effect of clinical guidelines in nursing, midwifery, and the therapies: a systematic review of evaluations. Qual Health Care 1998 7(4): 183-91.

Criticisms

Like evidence-based practice, meta-analyses have also come under criticism. Concerns center around:

  1. Using statistical analyses incorrectly and combining studies that should not be combined in a statistical summary.
  2. Using studies that are not RCTs and are not stringent enough methodologically to ensure the truth of the results.

A sampling of critical, peer reviewed articles appearing in MEDLINE between September and November 1999, include:

Clinical Guidelines

A clinical practice guideline is a systematically developed statement designed to assist the practitioner and patient make decisions about appropriate health care for specific clinical circumstances.
   Evidence-Based Medicine Glossary, from the Centre for Evidence-Based Medicine, Oxford, United Kingdom

Criticisms

Practice guidelines are often extremely helpful because they are concise and don't contain extraneous information. However, some criticisms include:

  1. Systematic reviews and meta-analyses present all the criteria used in arriving at their conclusion. By definition, any researcher should be able to duplicate findings based on the published criteria and methodology. Clinical guidelines often publish only the findings, and the criteria and methodology are not always available, forcing the user to accept the findings on faith or on the authority of the publishing body.
  2. Clinical practice guidelines are often dependent on the politics of organizations involved in the treatment.
  3. Because clinical guidelines are not always published as peer-reviewed articles in the medical literature, they are often difficult to locate.

A sampling of critical, peer-reviewed articles appearing in MEDLINE on the topic of clinical practice guidelines includes the following:

Peer-Reviewed Research Articles

To find research articles relevant to evidence-based practice in MEDLINE:

  1. Use PubMed Clinical Queries with Research Methodology Filters. This search is intended for clinicians, and uses built-in search "filters". If you are looking for everything on a subject area, don't use this page. The object of filtering is to reduce the retrieval to articles that report research conducted with specific methodologies.
    PubMed Clinical Queries | Search Tips | Sample Search
  2. Use appropriate MeSH headings such as:
    1. Evidence-based medicine (introduced in 1997)
    2. Meta-analysis (introduced in 1989)
    3. Randomized controlled trials (introduced in 1990)
  3. Use appropriate Publication Types such as:
    1. Randomized controlled trial
    2. Meta-analysis | Sample Search
    3. Review | Sample Search

Abstracts and Synopses

Evidence-based practice attempts to address the information overload that currently exists in the field of health care. It is impossible for any practitioner to analyze all the information published in a given field. Evidence-based practice synthesizes this overload of information for the practitioner, and at its best, does it well. Many services currently exist, offering practitioners abstracts or synopses of information of interest in their work.

  1. HealthLinks Care Provider Toolkit: Evidence-Based Medicine and Guidelines, Evidence-Based Practice and Guidelines | Sample Search
  2. ACP Journal Club, published bi-monthly by the American College of Physicians-American Society of Internal Medicine. 100 journals are regularly reviewed. Print copies are available in Health Sciences Library. Published six times a year. "Value-added" abstracts to journal artilces selected according to explicit criteria from major peer-reviewed medical journals. Subject areas: internal medicine. Most recent two years' featured articles available at web site; archives restricted to ACP members.
  3. Pediatric Evidence Based Medicine. Sponsored by University of Washington School of Medicine, applying evidence to clinical practice in pediatrics. Critically Appraised Topics (CATS) are synopses of evidence in a variety of clinical areas related to the care of children.
  4. POEMS, Patient-Oriented Evidence that Matters. Editors of Journal of Family Practice review over 90 peer-reviewed journals every month and identify articles most important to primary care physicians. note: subset available on the internet includes 1994-2001 only
    Sample Search

For More Information

Created: November 13, 1999
Revised: June 14, 2001

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