Evidence Based Medicine

Christopher H. Goss, MD MSc
Assistant Professor of Medicine
Division of Pulmonary and Critical Care Medicine
Department of Medicine
University of Washington

Introduction

Evidence-based medicine (EBM) has been described as "the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research."(1) In many respects, EBM is a response to some of the limitations of expert opinion and recommendations in the practice of clinical medicine. It relies on "formal rules applied in an explicit manner" to weigh evidence and enhance medical decision-making. (2) EBM creates a hierarchy of evidence and creates a format for critical appraisal of the literature. Given the explosion of medical research with new drugs and therapies for patients and the rapid proliferation of clinical research, this format of evaluation of evidence has become increasingly important. The following is a review of a limited sample of websites that address the topic of EBM; the list in clearly not exhaustive but should provide a resource to begin an evaluation of this topic.

1. David Sackett, et al. "Evidence Based Medicine: What It Is and What It Isn't," BMJ 1996: 312, no.7023.
2. Victor M. Montori and Gordon H. Guyatt. "What is Evidence-based medicine and why should it be practiced?" Respir Care 2001: 46(11):1201-1211.

Search

The search for websites addressing the topic "Evidence Based Medicine" entailed two separate approaches. The first approach was the use of a search engine (Google) with the search terms "Evidence Based Medicine." This search yielded a total of 41,000,000 sites. From this initial list, all commercial and private sites were excluded given the extremely large number of sites (defined by the an address with .com); this yielded 31,100,000. The top 100 sites were then reviewed, based on Google's hierarchy. Any site that charged a fee to view the information or used non-English language were also excluded. Then each site was briefly reviewed for content. All sites had to have EBM as the focus and list the authors of the website. They also had to list the last date of recent updates and have no apparent conflicts of interest. The criteria for an acceptable site included adequate definitions, level of depth of material, appropriateness and value of links, content, and whether the site actually addressed components of evidence based medicine.

A second approach was to solicit recommended sites covering the topic of "Evidence Based Medicine" from the primary and secondary membership of the Behavioral Sciences Assembly. A total of 16 responses to this request were returned. Once the two lists of sites were created (list 1 from the Google search and list 2 from the email responses), the sites on both lists were evaluated using the following criteria listed below. The goal was to list a minimum of 5 sites and a maximum of 10 sites that appropriately cover this topic. Given the sheer number of sites, this review is not an exhaustive review, but does represent well-established sites that provide excellent reference material and links to additional sites.

Best Sites

The ratings for each of the subcategories are as follows: 1 to 5 with 5 as the highest. 5 = excellent; 4 = good; 3 = satisfactory; 2 = poor; 1 = disappointing, serious flaws.

Toronto Centre for Evidence-Based Medicine/University Health Network: http://www.cebm.utoronto.ca/

1. Authority: This website is sponsored by the Center for Evidence Based Medicine, part of the University Health Network based at the University of Toronto and the Department of Medicine at Toronto General Hospital. Rating 5
   
2. Currency: The site has regular updates. The most recent updates were from April of 2005 regarding upcoming events sponsored by the Center for Evidence Based Medicine. Rating 4
   
3. Accuracy: The site has numerous resources including guides and syllabi for teaching evidenced based medicine in Critical Care Medicine. The site also includes a very good glossary of terms page and resource page. Rating 5
   
4. Navigation and readability: The site is very easily searched. The navigation through the site is also excellent. Rating 4
   
5. Utility: The site provides some nice EBM tables (number needed to treat tables), but you must provide some information (purportedly secure) to gain access. The majority of the material at the site is free of charge. The site does advertise several texts that cover the topic of EBM. The site also contains free PDA downloads to assist one in practicing EBM in the clinical setting. The site provides some excellent material on appraisal of the literature and has a very handy statistics calculator. The critical appraisal sheets are particularly useful and could be added to Journal Clubs to improve discussions and evaluations of the literature. Rating 5
   
6. Summary: Overall, this site was extremely informative. The site is a useful resource for those interested in teaching EBM. The curriculum materials are particularly instructive. This is an excellent site and is according rated:

Centre for Health Evidence: http://www.cche.net/che/home.asp and http://www.cche.net/usersguides/overview.asp

1. Authority: This website is sponsored by the Center for Health Evidence Alberta CA. The first CHE project was initiated in March 1999 under the Health Infostructure Support Program of the Canadian Office of Health and the Information Highway. The project got matching funds from the Alberta Heritage Foundation for Medical Research, the Universities of Alberta and Manitoba, the Capital Health Authority (Edmonton), the Winnipeg Regional Health Authority, InfoWard Inc. (now BHG Canada), and the Multimedia Advanced Computational Infrastructure initiative. This funding supported a demonstration project to explore uses of the Internet for supporting evidence-based decision-making in clinical practice settings. Rating 4
2. Currency: This site remains very active, with an annual summary of the accomplishments and activities of the Center for Health Evidence (with annual highlights going back to 1999). Rating 4
3. Accuracy: The material presented is accurate and useful. Rating 4
4. Navigation and readability: The site is reasonably accessible with a good site map. Rating 4
5. Utility: This web site hosts the User's Guides to the Medical Literature produced by JAMA. This part of the site is derived from work from Roman Jaeschke, Gordon H. Guyatt, David L. Sackett, and the Evidence Based Medicine Working Group, based on the Users' Guides to Evidence-based Medicine and reproduced with permission from JAMA. (1994;271(5):389-391) and (1994;271(9):703-707). Copyright 1995, American Medical Association. The project includes links to numerous projects related to the dissemination of EBM like the User's Guide Interactive (UGI) (http://www.usersguides.org). The UGI Web site is a secure site currently available with individual/institutional subscriptions to JAMA and/or Archives Journals or for individuals who register their Users' Guides textbooks. The UGI site contains an area for learners, practitioners and teachers of EBM. Rating 5
6. Summary: Overall, this is an excellent site but does not provide as much immediate user-friendly information fro those looking to learn more about EBM. It is an important site to visit for those interested in studies or initiatives related to EBM. Overall Rating:

Oxford Centre for Evidence Based Medicine: http://www.cebm.net/index.asp

1. Authority: This website is sponsored by the Oxford Centre for Evidence-based Medicine (EBM) Institute of Health Sciences Old Road Campus, Headington, Oxford, OX3 7LF, United Kingdom. The Centre was established in Oxford as the first of several centres around the UK whose goal is to promote evidence-based health care and to provide support and resources to others trying to practice and teach EBM. The highlight of the site is the EBM "Toolbox" which give one the "tools" to practice EBM. Rating 5
2. Currency: The site has regular updates with announcements of calendar events for the current year. Rating 5
3. Accuracy: The site has very accurate and up to date information regarding EBM. Rating 4
4. Navigation and readability: The website is set up into four main areas of EBM: learning EBM, doing EBM, teaching EBM and the EBM Toolbox. This makes it very easy to make one's way around the site and quickly find the necessary resources. Rating 5
5. Utility: The "Toolbox" is probably the most useful aspect of this website. Overall, this website has lots of downloadable material concerning the practice of EBM and weighing the evidence. It also contains a software program that is titled CATMaker; this program allows the user to create 1-page summaries of the evidence for particular medical scenarios. Rating 5
6. Summary: Overall, this is an excellent site. This was one of the most useful and easily accessed sites and is according rated:

Mount Sinai School of Medicine, Division of General Internal Medicine: http://www.mssm.edu/medicine/general-medicine/ebm/

1. Authority: This website is sponsored by Carlton Moore, Thomas McGinn, and Warren Ho in the Department of General Internal Medicine at Mount Sinai School of Medicine. Rated 3
2. Currency: No statement regarding currency and timing of updates was available on the site. Not rated
3. Accuracy: The material presented is accurate. Rated 3
4. Navigation and readability: The site is easy to access, but is a relatively uncomplicated site not requiring special attention to navigation. Rated 3
5. Utility: The most useful aspect of this website is the list of clinical prediction rules, clinical calculators and information of regardging the therapeutic number needed to treat in four basic areas of Medicine (Cardiovascular, Endocrine, Neurology, and Screening). The clinical prediction rules are probably the most useful resource at the site for those interested in pulmonary and critical care medicine. The guidance document pertaining to the evaluation of clinical prediction rules is very useful. The site also has a good selection of EBM links. The peer-reviewed summaries of evidence for clinical practice are not for public access. Rated 4
6. Summary: Overall, this was a good site, particular in relation to EBM tools.

Evidence Based Decision Making - Canadian Health Services Research Foundation: http://www.evidencebased.net/

1. Authority: Supported from a grant from the Canadian Health Services Research Foundation. The sites is run and maintained by Gordon Doig. The EBDM Net's online teaching cases are sponsored in part by unrestricted educational grants from the following companies: Baxter, Siemens, Novartis, and Roche. Grade 3
2. Currency: The online journal club is clearly active and up to date. It is not clear from the site how often other elements of the site are updated. The areas of the site involving EBM recommendations had a site addition within the last 30 days. Grade 4
3. Accuracy: The information in the Journal club gives authors and includes appropriate weighing of the evidence. Grade 3
4. Navigation and readability: The site is both readable and easy to navigate through. Grade 3
5. Utility: The site is has ongoing contributions to its journal club and evidence based medicine recommendations. The online teaching cases were useful with particular attention to treating asthma, abdominal pain, trauma and heartburn in the emergency department. These topics may be of use to pulmonary and critical medicine care providers. Grade 4
6. Summary: This was a generally useful site with some nice clinical applications of evidence based medicine. The online journal club and the evidence based medicine recommendations are good clinical resource but also a good example of how to weigh the evidence. Overall Rating:

Other sites that may be of interest include:

1. http://www.evidence-based-medicine.co.uk/What_is_series.html Sponsor: Hayward communications
2. http://www.sacme.org/Research/EBM_resources.htm Sponsor: Society for academic continuing medical education
3. http://www.jr2.ox.ac.uk/bandolier/index.html Sponsor: Initial print version was funded by the National Health Service R&D. Internet Bandolier is entirely dependent on sponsorship, and the good will of Oxford University Medical School information technology resources.
4. http://ebm.bmjjournals.com/ Sponsor: The British Medical Journal Publishing Group Limited
5. http://www.ahrq.gov/clinic/epcix.htm Sponsor: Agency for Health Care Policy and Research
6. www.shef.ac.uk/~scharr/ir/netting/ Sponsor: OxfordUniversity at Sheffield
7. http://library.umassmed.edu/EBM/ Sponsor: University of Massachusetts
8. http://www.cochrane.org/index0.htm Sponsor: The Cochrane Collaboration, an international non-profit and independent organization
9. http://www.acpjc.org/ Sponsor: AmericanCollege of Physicians
10. http://pedsccm.wustl.edu/EBJournal_Club.html