Evidence-based medicine on the Web

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Tapping into the latest scientific findings is not just for the academic elite. All you need is access to the Internet. Here’s a review of four Web resources.

The heart of evidence-based medicine is the application of the latest and best research to clinical practice. Thanks to online resources—including one that I developed—clinicians can conveniently apply evidence to their treatment plans at the point of care.

Good medicine involves more than the use of data. It also requires clinical experience, understanding the patients’ values, and good communication to support informed decision-making. The full spectrum of evidence-based medicine encompasses these elements, but in this article I would like to focus on the retrieval of reliable findings from well-conducted studies.

Defining “evidence-based”

Some Web sites consider their information evidence-based simply because the authors cite references. There are, in fact, only two rigorous methods for gathering evidence-based information: systematic literature searching and systematic literature surveillance.

Systematic literature searching: This method uses comprehensive approaches (such as databases covering millions of research articles, search engines, and explicit search criteria) to seek all relevant information on a topic. Because it yields the most results, important information is unlikely to be missed. However, these results are only thorough for the topics searched. They may not address topics or issues that were not specifically outlined in the search criteria, and so the results in mnay cases may be limited.

Systematic literature surveillance: This method scans a defined set of sources, such as the leading journals and journal review services. It then selects articles based on predefined criteria and catalogs or summarizes the information for retrieval. The prime advantage is that the latest information on a broad range of topics can be readily available soon after publication. But search results may not include all the applicable research to address your specific questions.

Nonsystematic approaches: Other “well-referenced” resources are able to provide only citation information. These offer a marginal level of validity when compared with unreferenced resources. They also may offer a fairly broad range of research data, but in the absence of the explicit methodology of systematic searches and surveillance, ensuring thorough coverage of the literature with minimal bias is virtually impossible.

Online evidence-based resources

When a question arises during the course of a busy day, clinicians need an immediate answer based on the most valid and up-to-date information. It should be written in a concise, easy-to-follow format and cover the full range of facts without superfluous detail. The following Web resources (Table 1) meet these standards, providing clinicians with the ability to quickly find evidence that has been critically evaluated and summarized for practical use.


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BMJ Clinical Evidence

BMJ Clinical Evidence(www.clinicalevidence.bmj.com) covers more than 250 conditions and is updated monthly. It searches the Cochrane Library, MEDLINE, and EMBASE for randomized, controlled trials and reviews of trials. Information is organized by topic, then treatment modality, with short paragraphs describing benefits, harms, and comments. Modalities are listed as beneficial, likely to be beneficial, trade-off between benefits and harms, unknown effectiveness, unlikely to be beneficial, or likely to be ineffective or harmful. This makes analysis quick and easy. The Web site also provides links to major guidelines and abstracts of recent articles identified from a systematic literature surveillance service (McMaster PLUS).

Advantages: The resource’s systematic searching is a primary strength, and its Updates from McMaster PLUS provide systematic literature surveillance. The comprehensive method makes it unlikely that any published trials of clinical significance will be missed.

Disadvantage: Information is limited to treatment-related questions for selected clinical conditions. The limited number of topics may decrease its usefulness.

Access: In addition to online access, BMJ Clinical Evidence publishes two print editions each year and can be used on a personal digital assistant (PDA). Several subscription packages are available, including a free trial subscription and a pay-per-view option.

DynaMed

DynaMed (www.ebscohost.com/dynamed) covers nearly 3,000 conditions and is updated daily. The update is it done directly or indirectly through journal review services, systematic reviews, drug information, and clinical guidelines. Cover-to-cover monitoring of journals allows letters, editorials, news, and departments to be included.

Articles are selected for clinical relevance and validity. Those posted are critically appraised and summarized objectively, precisely, and concisely. Related articles are synthesized for overall conclusions.

The resource is easy to navigate, with standardized templates that clinicians intuitively recognize. These templates cover all areas of clinical management: diagnosis, prognosis, treatment, prevention, and screening. Within each section, topics are organized by subsection and outline. And within the outlines, conclusions are presented first, followed by level-of-evidence labels, methods, results, and references, with links to full text when available.

Advantages: DynaMed is updated daily, with a methodology which ensures that the content is determined by the best available evidence. This selection process minimizes bias that can occur when authors selectively cite and describe articles to support specific opinions. In addition, DynaMed offers continuing medical education (CME) credit for physicians and American Academy of Nurse Practitioners contact-hours for nurse practitioners for point-of-care use. DynaMed content can be fully integrated into an institution’s electronic health-record system.

Disadvantage: In topics with large amounts of evidence, navigation may take some time.

Access: DynaMed subscriptions allow PDA access and remote access for all users at no additional charge. A free 30-day trial is available, and users can earn free subscriptions by serving as peer reviewers. The service also offers a free newsletter service, DynaMed Weekly Update, via e-mail, podcast, and Really Simple Syndication (RSS) feed.

InfoRetriever

InfoRetriever (www.infopoems.com) is a search engine for multiple databases, including: InfoPOEMs (an acronym for Patient-Oriented Evidence that Matters), which offers concise evidence-based summaries selected for clinical relevance and validity from more than 100 journals; Cochrane Database abstracts; selected guidelines; clinical decision rules; diagnostic test calculators; and the complete “Griffith’s 5-Minute Clinical Consult,” an expert-opinion resource.

Although InfoRetriever does not use diseases as a unifying theme, it includes brief summaries on more than 1,000 conditions using “Griffith’s.” InfoPOEMs is derived from systematic literature surveillance, and Cochrane Database abstracts are derived from systematic reviews.

Information is catalogued according to clinical topic. As searches are refined, users are asked to choose terms from the catalog. InfoRetriever organizes multiple hits first by type of information (e.g., diagnosis, therapy, or prognosis) and then by source database and levels of evidence.

Advantage: The resource includes clinical calculators that permit such interactive functions as calculating risks for specific diseases. In addition, InfoRetriever offers CME credits for point-of-care use.

Disadvantage: Users must read multiple hits from different sources to synthesize the available evidence.

Access: A one-year subscription includes online access, as well as InfoRetriever versions for the desktop computer and PDA. A free 30-day trial is available. Daily InfoPOEMs is sold as a subscription newsletter via e-mail and podcast.

TRIP Database

The Turning Research into Practice (TRIP) Database (www .tripdatabase.com) offers 150 free Internet resources that it catalogues by type. The database includes about 25 sources for systematic reviews and multiple sources for “evidence-based synopses,” some of which use systematic surveillance.

TRIP gives users access to more than 80,000 documents, such as guidelines and reviews, as well as millions of articles in PubMed. The content is not systematically evaluated on a document-by-document basis, but the resources are selected and catalogued with an “evidence-based medicine hierarchy” of systematic reviews, evidence-based synopses, guidelines (further organized by geographic region), clinical questions, core primary research, e-textbooks, and more. Search results can be narrowed using these categories.

In addition, TRIP provides 26 specialized search engines. These allow the same query to simultaneously search its database plus the top 10-15 journals (as defined by TRIP) within PubMed, providing an extensive list of results. TRIP also provides access to medical images and patient information leaflets. Content is updated monthly.

Advantage: TRIP Database provides a broad yet labeled set of resources from a single search.

Disadvantage: Users must read multiple hits from different sources to synthesize the available evidence.

Access: Online access to TRIP Database is free.

Dr. Alper is editor-in-chief of DynaMed and medical director of EBSCO Publishing in Ipswich, Mass.

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