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Journal of the Academy of Hospital Administration

Evience-Based Health Care: A Review

Author(s): Rajiv Kumar Jain

Vol. 12, No. 2 (2001-07 - 2001-12)

Traditionally, medical practice has been based on observation, knowledge, and experience. It is clear that each of these factors remains and always will remain, extremely important. But today there is a growing concern that these three factors alone are not enough if medical practice is to serve the needs of individuals in a more focused and effective manner.

Observation, for instance, have normally been personal observations drawn from individual clinical practice. It is inevitable that for any particular condition they are in most cases limited in number, and usually restricted to a particular population group.

Knowledge of the basic mechanisms of disease and path-physiology is essential to guide practice. Health care providers need information but many of their needs are not met. In many parts of the world, and particularly, in developing countries, the textbooks used during training are often the only information health care providers. Moreover, the textbooks are frequently out of date and there are limited, if any, opportunities for health workers to participate in continuing education. One landmarks meta analysis showed, for instance, that over 13 years elapsed between presentation of clear proof that thromobolytic drugs save lives after heart attack and recommending of this treatment in the majority of cardiology texts and reveiw articles. The cardiology authors simply could not keep abreast with randomized controlled trails appearing in nearly 100 different journals. Clinical guidelines can be helpful or dangerous, depending on how they are developed.

The health workers who wish to increase their knowledge and understanding often have few opportunities to update what they learned after their basic training. Medical journals are few and far between in developing countries, and those mailed from developed countries are expensive and arrive erratically. In any case, information on a particular topic may be scattered in different papers, in numerous journals, making it very difficult topic for health practitioners to get a good overview of all the data available on a given subject. Access to medical information over the interest is only now beginning to increase, while a Medline search provides information that is easy to access for those with the relevant technology, the output it hard to synthesize. In addition, the Medline consent it limited to abstracts, which may be incomplete. Consequently, the knowledge and performance of health care workers in developing counties are given a few opportunities to improve.

The heath worker also seeks the opinion of experts who have more experience I a particular area. When a recent survey asked physician what they would do when faced with a challenging clinical problem, that the most common response was to consult a respected authority. Unfortunately, authorities are not always the best source of advice and may not be completely objective in their view.

The shift to evidence-based medicine reflects not only the constant desire to improve practice but also the development that have taken place in clinical research and the increase inn medical literature.

Randomized controlled trails

Clinical research, for instance, now makes extensive use of randomized controlled trials because these are the most reliable methods of accessing the effectiveness of preventive or therapeutic health care interventions. Randomized controlled or health care units into groups to receive, the interventions(s) that are being compared. When the sample size is adequate, randomization ensures baseline comparability of prognostic variables, whether known or unknown.

However, the most appropriate research design depends on the health problems or question that is faced. For example, if the objective is to evaluate the accuracy of a diagnostic test, cross-sectional studies of patients suspected of having the disorder are required. Similarly, questions about prognosis can be answered by follow-up studies of patients having the disorder and corresponding controls.


In terms of methodology, meta-analysis is used to integrate results from more than one study to produce a summary estimate of the treatment effect across a number of studies. Meta-analysis is an application of a statistical technique used in observational studies (case-control studies and cohort studies) during stratifies analysis. In a meta-analysis in a systematic review of randomized controlled trials, however, each stratum is an individual randomized controlled trials.

Meta-analysis is only an analytical tool in a systematic review and not all systematic reviews necessarily include a meta-analysis. In the presence of disparities among trials, meta-analysis can help by stratifying different characteristics so as to identify the sources of the disparities. Meta-analysis is conducted in systematic review, when the reveiw includes more than one trial, although it does not necessarily follow that a summary estimate of the treatment effect is obtained. When there are clinical or biological disparities (heterogeneity) between trials, then using meta-analysis to produce a single summary estimate may be misleading and should be avoided.

Increase in medical literature

The world has many hundreds of medical journals, and thousand of journals with content that relates to medical issues and concerns. The amount of material being made available is rapidly increasing particularly as the internet makes it possible to publish more and to public more quickly.

This exposition in the amount of medical literature has been accompanied by the development of electronic database so that material can be better classified and more easily retrieved. At the same time, methods of search papers have improved to that it is now easier to find a large range of papers on a specific topic. However, when conducting a review of papers it must be remembered that the results will only be robust and conclusive if the trials included are of sufficient quality.

A list of short descriptions on databases, online journals and resources about evidence based health care is available in Appendix-1.

Evidence-based medicine

Evidence based medicine is the systematic, scientific and explicit use of current best evidence in making decisions about the care of individual patients. It is based on the following assumptions:

  • Clinical experience is crucial but systematic observation are necessary in order to summarize evidence;
  • Knowledge of the basic mechanisms of disease is also necessary but is an insufficient guide for selecting treatments for clinical practice; and
  • Understanding certain rules of evidence is necessary in order to interpret the literature correctly.

Evidence-based health care means that the policies and practices employed in the prevention and treatment of health problems are based on principles that have been proven through appropriate scientific methods. It must always be remembered, of course, that proving the clinical effectiveness of a procedure is not sufficient. It needs to be complemented by evidence that both health care provider and users are satisfied, and that the procedure is both cost-effective and feasible in different settings.

Quality in EBH

Evidence-based healthcare is all about quality. Quality in searching to find the studies addressing a particular questions, in applying appropriate quality filters to ensure only unbiased studies are included, in distilling the information into knowledge and making the knowledge understandable and useful with NNTs or likelihood ratios. There is another quality step as well, when the knowledge is combined with a practitioner's education and experience, knowledge of patient, and the values of people and society to make sensible decisions.

But quality comes in different forms. Quality assurance is making sure not only that the right things get done, but that wrong things don't. in clinical practice, audit is a shield of quality.


A. Databases :

CATbank -

A database of CATs (Critically Appraised Topics) developed for the Web by the National Health Care (UK) Research and Development Centre for Evidence-Based Medicine. A Critically Appraised Topic is a summary of findings that includes an appraisal of the validity and applicability of evidence identified in response to an answerable clinical question.

Cochrane Abstracts


Abstracts from the Cochrane Database of Systematic Reviews featuring evidence-based reviews conducted by contributors to the Conchrane Collaboration, of randomized clinical control review studies published in the biomedical literature. The reviewers are critical assessments in structured abstract format.

This portion of The Cochrane Library is available for free on the Internet, with unrestricted access.

Database of Abstracts of Reviews of Effectiveness (DARE)

Includes structured abstracts of systematic reviews, critically appraised by reviewers at the (U.K.) National Health Care Service Centre for Reviews and Dissemination at the University of York, England. Reviews are identified from a variety of sources and assessed according to a set of quality criteria. Also contained in the Cochrane Library; this version of DARE is available for free on the Internet, with unrestricted access.

Evidence Based Medical Review:

Best Evidence (OVID)

Full text of the journals, ACP Journal Club and Evidence-Based Medicine. Includes abstracts and critiques of articles published in the top clinical journals that are the most methodologically sound and clinically relevant. Access limited to AHSC/UA/UMC networked computers and to individuals with University affiliated accounts.

Evidence Based Medical Reviews: Cochrane Database of Systematic Reviews (OVID)

The Cochrane Database of Systematic Reviews includes the full text of regularly updated systematic reviews of the effects of healthcare as prepared by the Cochrane Collaboration, an international network of practitioners and researchers. This version of "Cochrane" is linked to OVID MEDLINE, allowing searchers in MEDLINE to limit and link to reviews in this version of the "Cochrane" database. Access is limited to AHSC/UA/UMC networked computers and to individuals with University-affiliated accounts.

National Guidelines Clearningshouse

A searchable database of evidence-based clinical guidelines sponsored by the US Agency for Health Care Policy and Research in partnership with the American Medical Association and the American Association of Health Plans.

Netting the Evidence

A gold mine of EBHC resources including database, online journals, software, tutorials and access to organizations. Sponsored by the University of Sheffield (UK) School of Health and Related Research. Very comprehensive!

Prevention Guidelines from the U.S. Centers for Disease Control

The UK's National Health Service Research and Development's CEBM is a premier center for evidence based medicine. Their web site features analytical tools, articles about EBM practice, and information about EBM journals.

PubMed: Clinical Queries Using Research Methodology Filters-

A feature of the National Library of Medicine's PubMed free Internet MEDLINE search service. This specialized feature is geared to clinicians and has built-in "filters" in four study categories--therapy, diagnosis, etiology, and prognosis. You may indicate whether you wish your search to be more sensitive (i.e., include most relevant articles but probably including some less relevant ones) or more specific (i.e. including mostly relevant articles but probably omit a few). Available for free on the Internet, with unrestricted access.

The Cochrane Library

The premier EBHC database resource, produced by the cochrane Collaboration, an international network of EBHC investigators. Includes: The Cochrane Database of Systematic Reviews - regularly updated reviews of the effects of health care; database of a Abstracts of Reviews of Effectiveness (DARE) - critical assessments and structured abstracts of systematic reviews published elsewhere; The Cochrane Controlled Trials Register - bibliographic information on controlled trials; and other sources on the science of reviewing research and evidence-based health care. Access limited to The University of Arizona, Arizona Health Sciences Center and University Medical Center.

Evidence Based Medicine:

Finding the Best Clinical Literature

A helpful overview from the University of Illinois at Chicago - Peroria branch. "This guide is designed to assist health care professionals and students in becoming effective and efficient users of the medical literature".

Evidence-Based Health Related Discussion lists

A peer-reviewed web site featuring extensive links to information on EBHC-related organizations, online tools and tutorials, and guides to searching the biomedical literature, among other useful resources. This site is maintained by staff at the library of the Health Science-Peoria, University of Illinois at Chicago, in collaboration with the National Network/Libraries of Medicine Greater Midwest Region and the Committee on Institutional Cooperation (CIC) Health Web Project.

Suny Health Sciences Evidence-Based Medicine Course


An office text from the state University of New York Downstate Medical Center covering EBM basics, tips on searching the biomedical literature, and evaluating studies.

The Medical Literature as a Resource for Evidence Based Care


Bu KA McKibbon, N. Wilczynski, RS Hayward, CJ Walker-Dilks, and RB Haynes of the Health Informatics Research Unit, McMaster University. A working paper overview of EBHC focussing on the critical appraisal of the biomedical knowledge base, and in particular the use of the MEDLINE database as a source for identifying "evidence".

U.S. Health Services/Technology Assessment Text (HSTAT)

Searchable access to the full-text of: clinical practice guidelines, quick-reference guides for clinicians, consumer brochures, and evidence reports from the Agency for Health Care Policy and Research (AHCPR); AHCPR technology assessment reports; National Institutes of Health consensus development conference and technology assessment reports; and the Public Health Care Service Preventive Services Task Force Guide to Clinical Preventive Services, among other resources. Available for free on the Internet, with unrestricted access.

B. Online Journals: ACP Journal Club

Published by the American college of Physicians. This is provides access to two years' worth of the journals' tables of content with some full text available. The entire full text of the ACP Journal Club is includes in the Cochrane Library. This abbreviated version of the ACP Journal Club is available for free on the Internet, with unrestricted access.



Important online journal resources of evidence-based reviews, searchable by subject or individual journals issues. Bandolier features extensive discussions of numbers needed to treat and numbers needed to harm, important "threshold" values in selecting an appropriate patient intervention strategy. Much of this data is presented in easy-to-use and interpret charts and tables. Available for free on the Internet, with unrestricted access.

Evidence-Based Medicine

Published by the American College of Physicians, covering summaries of and commentary on evidence-based articles as they appear in the biomedical literature. All journals issues, dating back to Nov./Dec. 1995, are online and searchable.

Journals of Family Practice


This site provides an extensive list of evidence-based medicine resources, with a focus on the POEMS approach (Patient Oriented Evidence that Matters). POEMS can be found though an unsophisticated search interface or by using the "Find In Page" features of your Web browser software. Available for free on the Internet, with unrestricted access.

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