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Ekaterini Papadopoulou
Lemieux Library and McGoldrick Learning Commons
(206) 296-2341

What Is Evidence-Based Medicine?

"Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients."

Sacket DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS. (1996) Evidence based medicine: what it is and what it isn't. BMJ 312: 71-2.

Evidence-Based Nursing - A way of providing nursing care that is guided by the integration of the best available scientific knowledge with nursing expertise. This approach requires nurses to critically assess relevant scientific data or research evidence, and to implement high-quality interventions for their nursing practice. (NLM PubMed MeSH)

Formulating Answerable Clinical Questions

Well-built clinical questions need to be both directly relevant to patients' problems and phrased in ways that direct your search to relevant and precise answers. In practice, well-built clinical questions usually contain four elements, encapsulated by the acronym PICO:

Patient, Population or Problem

  • What are the characteristics of the patient or population?
  • What is the condition or disease you are interested in?

Intervention or exposure

  • What do you want to do with this patient (e.g. treat, diagnose, observe)?


  • What is the alternative to the intervention (e.g. placebo, different drug, surgery)?


  • What are the relevant outcomes (e.g. morbidity, death, complications)?

Example 1

Your next patient is a 72-year-old woman with osteoarthritis of the knees and moderate hypertension, accompanied by her daughter, a lab tech from the hospital. The daughter wants you to give her mother a prescription for one of the new COX-2 inhibitors. She has heard that they cause less GI bleeding. Her mother is concerned that the new drugs will mean more out of pocket costs each month.

Patient, Population or Problem
  • 72 year old woman with osteoarthritis of the knee and moderate hypertension

Intervention or exposure

  • COX-2 Inhibitor


  • other NSAIDS


  • less GI bleeding
  • pain control
Specific Question:
In a 72 year old woman with osteoarthritis of the knee, can COX-2 Inhibitor use decrease the risk of GI Bleeding compared with other NSAIDs?

Critical Appraisal Tools

Systematic Reviews and Meta-Analyses

A Systematic Review is a literature review focused on a single question which tries to identify, appraise, select and synthesis all high quality research evidence relevant to that question. Systematic reviews use explicit methods to identify, select, and critically evaluate relevant research.

Meta-analyses are systematic reviews that combine the results of several studies using quantitative statistics.

Systematic reviews minimize the possibility of bias by using explicit criteria, and expand the relevance of individual studies with limited scope, but ...

Only a small number of clinical topics are covered by systematic reviews, because they require years of effort to develop.

Clinical Practice Guidelines

Guidelines are systematically developed statements of appropriate care designed to assist the practitioner and patient make decisions about appropriate health care for specific clinical circumstances.

Guidelines from reputable, authoritative organizations are usually based on the most current, relevant research, but ...

Guidelines are developed using widely varying standards. Cost may be considered as well as health outcomes.

Professional specialty organizations and associations are often good resources for evidence-based practice guidelines. Ex. AWHONN.

Evidence Summaries and Structured Abstracts

Because it is difficult for a clinician to analyze all the information in a field, resources such as UpToDate offer summaries of evidence-based information on a topic.

Meta-Search Engines

A metasearch engine is a search engine that searches multiple other search engines simultaneously and combines the results.