Current issues of ACP Journal Club are published in Annals of Internal Medicine


Evidence-based medicine and the Internet

ACP J Club. 1996 July-Aug;125:A14. doi:10.7326/ACPJC-1996-125-1-A14

Computer access to information provides an increasingly important resource for the efficient and effective practice of evidence-based medicine. Computer technology and information services, however, are changing even more rapidly than medical knowledge, and it is a challenge for practitioners to make optimal use of them. One of the fastest changing new technologies is the Internet, a world-wide computer network with 10 to 20 million users in more than 80 countries. The Internet began in the 1960s as a means to connect geographically dispersed U.S. military computers and was adopted by universities in the 1980s and home and business computer users in the 1990s. The Internet actually is not a single computer network but consists of thousands of smaller computer networks at universities, businesses, hospitals, and other organizations. These local networks in turn are connected to electronic backbones that traverse national borders and form what we call the Internet.

The Internet changes both how we access information and what we can view. Although the Internet can be used to search traditional text-based bibliographic databases, such as MEDLINE, its key innovation is provided by the World Wide Web (WWW or Web), which implements “network-based hypertext.” In hypertext, pages are linked together, either hierarchically, as in a print reference's table of contents, or vertically, similar to the cross-reference in a textbook. Links are indicated by “hot text” that the user clicks on to go to the linked material. The power of this feature of the Web is that the hypertext links can stretch across the entire Internet, not just within documents or between local collections of documents. Thus, the link can be to a page in the same computer or to another computer on a different continent. The only difference is that material on the Web in another country or continent takes longer to download and display on the screen, especially when the connection is made by modem or is at peak “traffic” times when the service has many users. Internet searching of bibliographic databases, however, is often at much faster connect speeds (hence incurring lower connect charges) for those directly linked to the Internet, as many worksites are now. In addition, the Web provides for much more sophisticated formatting, including stylized (and hence easier to read) text, images, and even sound and video.

Why is the Internet important to evidence-based medicine? All of the major online database vendors—for example, the National Library of Medicine (NLM, Bethesda, Maryland); Ovid (New York, New York); Dialog (Palo Alto, California); CompuServe (Columbus, Ohio); and America Online (Vienna, Virginia)—provide use of their services over the Internet. The Internet also provides access to a much greater diversity of information than the traditional bibliographic databases. Thus, one can consult an increasing range of full-text information, including textbooks, curricula, practice guidelines, and systematic reviews. The Internet also provides entry to a spectrum of communication services (1), including electronic mail, discussion lists, and newsgroups through which health care providers from around the world can share information. An increasing number of medical journals and organizations have Web “home pages,” including the American College of Physicians (ACP), the American Medical Association, and the American Cancer Society, which provide news, contents pages for upcoming issues of journals, and an expanding array of full-text content, often in advance of print publication. Online subscriptions to full-text journals will soon be more widely available.

How does one get on the Internet? Most universities and many hospitals are already directly connected, and employees can get their own connections and software advice or service there. Those without dedicated network connections through their worksite can connect by modem, through any one of a rapidly growing number of Internet provider companies. Most of the larger consumer online services, such as CompuServe and America Online, are adding Web capability. Access can also be obtained in all but the most remote communities by local Internet service providers, which provide software to connect and allow dialing in by modem without incurring long-distance calling charges.

To use the Web in addition to the Internet connection, a piece of software is required called a Web browser. The best-known browsers are Netscape Navigator (Netscape Communications, Mountain View, California); Internet Explorer (Microsoft Corporation, Redmond, Washington); and Mosaic (National Center for Supercomputing Applications, Urbana, Illinois). Web browsers provide automated dial-up and connection with the Web and simple searching services for retrieval of Web pages around the world. Each page on the Web has a unique address, called a uniform resource locator (URL). URLs always begin with “http:” and are increasingly ubiquitous in advertisements and news stories. For example, is the URL for ACP Online. Web browsers can be used to access a page either by directly entering the URL or by linking from another page that “points” (links) there.

What evidence-based medicine resources are available on the Web? Although the potential for this medium is vast, the range of medical resources is relatively modest to date. Some of the current offerings are clearly based on evidence, while others are not, and it is not always easy to tell the difference: User beware! Much of the available information comes from academic health centers and health-related government agencies. Commercial publishers have been slow to embrace the Web because of concerns over protection of their intellectual property and the difficulties in charging for it when much of what is currently on the Web is free to users. Thus, access to the evidence-based sources we most commonly use, such as journal articles, is limited, and no single index is available for medical information on the Web. Nonetheless, several evidence-based resources are available now. For example, several implementations of Web-based MEDLINE have been developed. The original version was WebMEDLINE, developed at Stanford University for users of the University of California's MELVYL MEDLINE system (2). More recently, the NLM has implemented Internet Grateful Med (, which provides a Web-based front-end to MEDLINE and other NLM databases for anyone who has a valid NLM password. Other commercial companies that have developed Web front-ends to MEDLINE include Ovid ( and Silver Platter (

Several comprehensive search systems index vast portions of the Web, such as InfoSeek (, Alta Vista (, Lycos (, and Yahoo ( These indexes do not discriminate between clinical and nonclinical information or between someone's personal Web page and that of a prestigious journal or medical center. Recently, a number of clinically focused indexes have been developed, including Medical Matrix (, MedWeb (, Physician's Guide to the Internet (, Doctors Guide (, and CliniWeb ( The latter allows searching of clinically oriented Web pages by MeSH disease terms.

Some full-text resources are also available on the Web. The NLM Web site contains the HealthSTAR database, with several evidence-based resources, such as the AHCPR Practice Guidelines, the PHS Guide to Clinical Preventive Services, the HIV/AIDS Treatment Information Service, and the NIH Consensus Conference Reports ( Bandolier, published by the Oxford Anglia National Health Service Region in the United Kingdom, contains concise, evidence-based reviews of current medical care issues ( On a more specific topic, the Helicobacter Foundation, with commercial support, maintains a Web site devoted to the dissemination of scientific information concerning disease caused by Helicobacter pylori (

Other evidence-based services currently available for computers in non-Internet formats, such as diskettes and CD-ROM, will probably also be available soon on the Web. These include the reviews of the Cochrane Collaboration (3) as well as this publication, ACP Journal Club. Some publishers already offer tables of contents, abstracts, and some full-text material on the Web, including the American College of Physicians (see URL above), the American Medical Association (, and the BMJ Publishing Group (

Another advantageous Web feature allows searching beyond specific discrete databases. One example of this is Physician's Home Page, a service of Silver Platter, which features not only access to databases but also to critical reviews of literature ( A great deal of information on evidence-based medicine itself is available from McMaster University, including users' guides to the medical literature (

The Internet also provides information for patients and the public. Savvy consumers can now get access to a great deal of information on their diseases and treatments from the Web as well as from discussion groups, electronic mail lists, and information archives (4). They can also learn about clinical centers and support groups that provide services. Patient use of the Internet can be a double-edged sword, especially when it comes to providing evidence-based care. A recent report in The New York Times quoted several physicians whose patients demanded unproven treatments, usually based on anecdotal evidence amplified by world-wide discussion on the Internet (5). This dilemma highlights one of the problems with the Web. As noted above, an oft-touted virtue of the Web is that it allows anyone to become a publisher, simply by putting pages on an Internet server. Although this is a benefit for a democratic society in general, it can be problematic for an activity like evidence-based medicine where practitioners try to make life-and-death decisions based on sound evidence that is properly peer reviewed. Although all of us want our patients to have access to the same high-quality, evidence-based information that we have, the Internet has no peer review or other mechanisms to refute unscientific information (6).

Another problem with the Web can be its slowness. Although the ability to fetch a page in Adelaide, Australia, and display it on a computer in Portland, Oregon, is an impressive technical achievement, the speed of obtaining pages can be slow, especially pages laden with pictures, which take a longer time to transmit than text. This is particularly problematic for users connected via modems, which transmit data much more slowly than do computers connected directly to networks.

In the future, the Web will not only change the way we access information but also how we produce it. For example, some Web pages are no longer static entities like journal papers but are updated regularly as evidence changes. Cochrane Collaboration reviewers, for example, agree to continually peruse the literature for new trials in their areas and update their reviews as new evidence becomes available. This may require changes in promotion and tenure policies, which are currently geared toward counting specific numbers of publications. Few medical schools at this time have policies regarding electronic publication, and it is likely that fewer recognize the ongoing commitment that maintaining an electronic information resource requires.

The advantages of the Internet medium indicate that this technology will play an increasingly important role in evidence-based care. Indeed, it will likely become the main means by which scientific information in medicine is disseminated, based on its widespread availability and reduced publishing and mailing costs. One particular benefit for evidence-based medicine could be the development of pages containing digested, summarized, and regularly updated bits of evidence that will allow more efficient implementation of this approach to care. But for this to happen, better methods for navigating the Web and focusing on high-quality, evidence-based content will need to emerge. In addition, issues related to copyright, economics, and peer review will need to be resolved before the Internet becomes a comprehensive, dependable, and indispensable tool for clinical practice.

William Hersh, MD
Oregon Health Sciences University
Portland, Oregon, USA


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2. Detmer WM, Shortliffe EH. A model of clinical query management that supports integration of biomedical information over the World Wide Web. Proc Ann Symp Comput Appl Med Care. 1995;19:898-902.

3. Sackett DL.The Cochrane Collaboration. ACP J Club. 1994 May-Jun;120:A11.

4. Jimison HB, Sher PP. Consumer health informatics: health information technology for consumers. J Am Soc Info Sci. 1995; 46:783-90.

5. Gilbert S. On-line health tips offer vast mountains of gems and junk. The New York Times. 1996 April 10;D10.

6. Kassirer JP, Angell M. The Internet and the journal. N Engl J Med. 1995;332:1709-10.