INFORMATION RESOURCES IN SUPPORT OF EVIDENCE BASED HEALTHCARE


Practicing Evidence-Based Care involves the "conscientious and judicious use of current best evidence in the health care of individuals and populations"(1). Finding, analyzing and synthesizing relevant information is often a time-consuming and dauting task for busy clinicians. Fortunately, the past few years have seen numerous advances in the production of tools and guides which identify relevant sources and aid in critical appraisal of the literature. Evidence-based abstracting services, systemic review services, online literature searching, and frequently updated textbooks streamline the process of finding and appraising the evidence, and assessing its clinical relevance.

Which resources to use depends on a number of factors including

  1. available time,
  2. available databases,
  3. subject matter and domain of the question,
  4. currency and level of evidence desired, and
  5. how well the issue lends itself to study.
A time saving initial question is to ask is "how likely is it that there are high quality studies that have produced valid and clinically important evidence specifically addressing this issue?"(2) Based on your assessment of the question, you can then choose among potential information resources. Sources of information and evidence for clinical care may include colleagues, textbooks, journal articles, clinical guidelines, care maps or disease guidance systems. Descriptions of useful evidence based resources are included below:

Textbooks
Primary Literature Sources
Value-Added Sources
Searching the Evidence Based Medicine Reviews database on BUMC MEDLINE Plus
Internet Resources

Textbooks

High quality textbooks should be comprehensive, frequently updated, contain explicit links to evidence, and organized for easy and effective use. A detailed table of contents and index are key. Many textbooks are now available both in-print and in an electronic format (CD-ROM or on the WWW).

A good example of an electronic textbook is Scientific American Medicine CD-ROM (usually referred to as SAM-CD), the compact disk read-only memory version of the comprehensive medical textbook. SAM-CD enables full-text Boolean searches by keyword, outline topic, or chapter. An online dictionary helps the user to check spellings or select partially remembered words. The electronic text is updated quarterly, and is available for searching in the LRC.

An addition 30 biomedical textbooks are available on the STAT!-Ref program, which contains the most current edition of authoritative texts such as Harrison's Principles of Internal Medicine, Goodman & Gillman's The Pharmacological Basis of Therapeutics, Current Critical Care Diagnosis & Treatment and many others. STAT!-Ref allows users to search a textbook individually, or to select up to 30 titles to be searched simultaneously. All search results, full text and tables-of-contents can be browsed and printed. Additional features include chapter bibliographies, links to relevant journal article citations from the MEDLINE database, and selected tables, figures and illustrations. STAT!-Ref is available for searching in the LRC and from the terminals on the 12th floor of the library. Remote access to STAT!-Ref is available from most computers in Medical Center buildings.

Primary Literature Sources

Because most practitioners require the most current information available, a search of the current medical literature may be especially useful for locating evidence. The need for skills in searching and critical appraisal is greatest, however, when searching for evidence in the primary literature.

MEDLINE, produced by the National Library of Medicine in Bethesda, Maryland, is the premier bibliographic database of biomedical journal literature (including nursing and dentistry). MEDLINE dates from 1966 to the present, and includes the printed Index Medicus, Index to Dental Literature and Index to Nursing Literature. MEDLINE is searchable by author, journal, textwords (title and abstract words) and controlled vocabulary (MeSH -- medical subject headings). While the roughly 3,800 journals indexed in MEDLINE have been selected for their overall reliability and quality, the articles must be scrutinized carefully for their validity and quality evidence. The MEDLINE database is available on the BUMC MEDLINE Plus search system. BUMC MEDLINE Plus search system also includes the Core Biomedical Collections of 60 full-text biomedical journals, complete with charts, tables, graphs and illustrations.

EMBASE is the Excerpta Medica database for biomedical and pharmaceutical journal articles. This database indexes 3,500 journals, a somewhat different spectrum compared with MEDLINE, with more international (including European and Canadian) journals and fewer state, nursing, veterinary medicine, or dentistry journals. EMBASE is available from 1988 to the present time, and is searchable by a controlled vocabulary which is similar to the MeSH (medical subject headings). EMBASE is especially useful for searching for evidence regarding drugs and pharmaceuticals. As with MEDLINE, the individual articles cited must be scrutinized for their validity and quality. EMBASE is available on the Dialog search system, which can be accessed by a reference librarian for a fee.

Current Contents is produced by the Institute for Scientific Information, and is published weekly. It includes coverage of over 6,000 scholarly and scientific journals, including journals in clinical medicine for the most recent two years. Current Contents indexes articles much more rapidly than either MEDLINE or EMBASE, with a lead time of approximately a month between publication and indexing, as opposed to 1.5 to 6 months for MEDLINE or EMBASE. Because there is no controlled vocabulary, Current Contents requires users to search for all possible synonyms and forms (singular, plural, U.S. and British spellings, etc.) for the concepts they are searching. The chief advantages of Current Contents are speed and breadth of coverage if very current material is required. As with MEDLINE and EMBASE, the reader must scrutinize each article for its validity and quality. The printed version of Current Contents is available in the Library reference area. The online version is available on the Dialog search system, which can be accessed by a reference librarian for a fee.

Value-Added Literature Sources

Evidence Based Abstract Services Best Evidence, the electronic version of the ACP Journal Club (ACPJC) and the Evidence Based Medicine journal, is a good example of an evidence-based abstract service. Best Evidence is produced by McMaster's Health Information Research unit and published by the American College of Physicians and the British Medical Journal publishing group. The bimonthly paper periodical ACPJC and the yearly Best Evidence contain peer-reviewed structured abstracts of the best-available studies pertinent to the practice of internal medicine. Article selection criteria are based on EBM principles and are explicitly stated in each issue. The articles are analyzed, then summarized in "value-added" structured abstracts, which also include appended commentary by content experts. With Best Evidence, the complete collection of structured abstracts and commentaries from 1993 to the present can be searched on BUMC MEDLINE Plus' Evidence Based Medicine Reviews database.

Structured Reviews An example of a structured review database is the Cochrane Database of Systematic Reviews, whcih is produced by the Cochrane Collaboration. The Cochrane Collaboration was established in Britain in 1992, and is presently composed of numerous centers around the world. Its goals include the creation, maintenance, and dissemination of high quality systematic reviews of randomized controlled trials (RCT). Reviews involve exhaustive searches for all RCT, both published and unpublished, on a particular topic. The studies are analyzed using standardized methodology and meta-analysis. The current database includes more than 65 completed reviews in internal medicine, and another 160 or so currently under construction. The reviews are mainly on therapies, although an increasing number of reviews on diagnostic topics are being developed. The Cochrane Database also includes abstracts of non-Cochrane reviews and a database on methodology for conducting systematic reviews. The Cochrane Database is available on BUMC MEDLINE Plus' Evidence Based Medicine Reviews database.

Searching Evidence Based Medicine Reviews on BUMC MEDLINE Plus

To access EBMR on BUMC MEDLINE Plus, simply login to the WWW or Windows version of BUMC MEDLINE Plus, and access the MEDLINE database. Conduct your search, then use the limit command to select Evidence Based Medicine Reviews. This limit option will restrict your search to citations which meet evidence-based criteria.

Other features include links between existing databases and EBMR. This structure allows users to follow a complete train of thought: moving from a MEDLINE citation to a particular review, to the full text of that reviewed article, to articles referenced therein. Finally, expert topic searches allow users to recreate the searches designed by members of the Cochrane Collaboration to get the latest information on that topic. Use this link for a more detailed description of the EBMR database.

Internet Resources

Tutorials & Information on Searching the Medical Literature for Evidence

"How to Read a Paper" series in the BMJ

Evidence-based Journals and Publications

Additional Internet Sites


For more information, contact a reference librarian at refquest@med-libwww.bu.edu or 617-638-4228.

Reference
Evidence Based Medicine Toolkit, Introduction to Evidence Based Medicine, http://www.med.ualberta.ca/ebm/ebm.htm.