Existing knowledge can prevent
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Existing knowledge can prevent…. Waste Errors Poor quality clinical care Poor patient experience Adoption of interventions of low value Failure to adopt interventions of high value

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Existing knowledge can prevent

Existing knowledge can prevent…



Poor quality clinical care

Poor patient experience

Adoption of interventions of low value

Failure to adopt interventions of high value

Source: Sir Muir Gray, Chief Knowledge Officer of Britain’s National Health Service. Quoted on http://www.nks.nhs.uk/.

Learning objectives

Learning Objectives

  • At the end of the presentation, learners will:

    • be able to define evidence based medicine

    • be able to utilize a well-built clinical question to facilitate an efficient search

    • understand the 4S approach to organizing medical evidence

Existing knowledge can prevent

“Evidence-based medicine is the integration of best research evidence with clinical expertise and patient values”

Sackett DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS: Evidence based medicine: what it is and what it isn’t. BMJ 1996;312:71-2.



Best research





What is EBM?

Evolution of ebm in the literature

Evolution of EBM in the Literature

  • Term first appeared in the literature in a 1991 editorial in ACP Journal Club Volume 114, Mar-April 1991, pp A-16

  • Seminal article by the Evidence-Based Medicine Working Group published in JAMA Volume 268, No. 17, 1992, pp 2420-2425

Fundamentally new approach becomes widely recognized

Fundamentally new approach becomes widely recognized

  • JAMA published a series of Users’ Guides to the Medical Literature that served as the first learning tools

  • Courses were developed in residency training and medical school curricula

  • The first handbook, Evidence-Based Medicine: How to practice and teach EBM, by Sackett, et al, was published in 1996. Fourth edition published in 2010.

  • New York Times listed EBM as one of its ideas of the year in 2001

  • BMJ listed EBM as one of the 15 greatest medical milestones since 1840

Integration of ebm into medical school curricula patient doctor courses

Integration of EBM into medical school curricula patient-doctor courses

Information retrieval for evidence based patient care

Information Retrieval for Evidence Based Patient Care

  • Using research findings versus conducting research

  • Retrieving and evaluating information that has direct application to specific patient care problems

  • Selecting resources that are current, valid, and available at point of care

  • Developing search strategies that are feasible within time constraints of clinical practice

Key developments that streamlined the practice of ebm

Key developments that streamlined the practice of EBM

  • Advances in ease of accessing and understanding information

  • Development of preprocessed (preappraised) tools

  • Improvements in search interfaces to MEDLINE

  • Collaboration between EBM Working Group and National Library of Medicine in development of “hedges”, clinical queries that filter search results by “type of study” to match clinical question

  • Dissemination of systematic reviews of primary studies and growth of the Cochrane Collaboration

Cochrane collaboration

Cochrane Collaboration

  • Cochrane Database of Systematic Reviews

    • Part of the Cochrane Library (1996)

    • Over 3,000 reviews

    • Mostly Treatment; Diagnosis since 2008

    • Eyes & Vision Research Group includes 156 reviews

    • Among the highest level of evidence upon which to base treatment decisions

    • Access full text of reviews through Ovid

Systematic review

Systematic Review

  • Analyzes data from several primary studies to answer a specific clinical question

  • Provides search strategies and resources used to locate studies

  • Includes specific inclusion and exclusion criteria (results in less bias)

  • Meta-Analysis (subclass) statistically summarizes results of several individual studies

Ongoing developments

Ongoing Developments

  • Continuing development of point of care (POC), evidence based summaries, e.g., Dynamed, Up to Date

  • Evolving decision support tools that embed evidence based summaries in the electronic medical record and clinical workflow

  • Uptake of EBM process by health policy, nursing, allied health, and psychosocial fields

Focused approach saves time

Focused Approach Saves Time

  • You will not have time to read all of the important articles in the literature

    • 500,000 new medical articles published each year

  • You will be expected to quickly make increasingly complex decisions

    • Sorting the valid information from the less useful takes time away from decision making

  • You will be expected to “standardize” your practice

    • Standard of care critical in health care reform and legal issues

Ebm process 5 steps

EBM Process – 5 Steps

  • ASSESS: Recognize and prioritize important patient problems

  • ASK: Construct clinical questions that facilitate an efficient search

  • ACQUIRE: Track down the best evidence to answer the questions

  • APPRAISE: Systematically evaluate best available evidence for validity, importance, and usefulness

  • APPLY: Interpret the applicability of evidence to specific problems, given patient preferences and values

Step 1

Step 1

  • ASSESS the clinical problem

    • Begin with the patient encounter

    • Select question that

      • Is most important to the patient’s well being

      • Fills gaps in your clinical knowledge

      • Is feasible to answer in the time available (30 minutes per week)

Step 2

Step 2

  • ASK focused clinical questions

  • Four common types of clinical questions:

    • Therapy/prevention

    • Diagnosis

    • Etiology

    • Prognosis

Well built clinical questions

Well Built Clinical Questions

  • Deal with patient management issues

  • Contain elements of PICO format

    • Patient/Population

    • Intervention

    • Comparison Intervention (if useful)

    • Outcome

  • Facilitate an efficient search

Example therapy prevention question

Example – Therapy/Prevention Question

  • In patients with ocular hypertension, will treatment with timolol versus no treatment decrease the risk of developing glaucoma?

Extract search terms from question

Extract search terms from question

  • Therapy/Prevention Question

    • In patients with ocular hypertension [Patient/Population], does treatment with timolol [Intervention] versus no treatment [Comparison Intervention], decrease the risk of developing glaucoma [Outcome]?

  • Search Terms: ocular hypertension, IOP,timolol, glaucoma, (POAG)

Step 3

Step 3

  • ACQUIRE: Track down the evidence to answer the question

  • Use the 4S approach to select the most likely resource

  • Start with the highest level resource available

Best study design for type of question

Best Study Design for Type of Question

Existing knowledge can prevent

Randomized controlled trials are considered the best studies for assessing therapeutic interventions.

Source:  Sackett, D.L., Richardson, W.S., Rosenberg, W.M.C., & Haynes, R.B. (1996). Evidence-Based Medicine: How to practice and teach EBM. London: Churchill-Livingstone.

4s hierarchy

4S Hierarchy

Information pyramid

Information Pyramid

POC Tools: Up-to-date, Dynamed, FIRSTConsult, ACP PIER

ACP Journal Club

Evidence Based Ophthalmology

Cochrane and other Systematic Reviews (OVID EBMR)

MEDLINE Searches with Clinical Queries

SOURCE: Haynes, R. B. (2001). Of studies, syntheses, synopses, and systems: the “4S” evolution of services for finding current best evidence. Evidence-Based Medicine, 6 (2), 36-38. Retrieved 2-07-07 from http://ebm.bmj.com/cgi/reprint/6/2/36

Critically appraised content

Critically Appraised Content

Appraise the filter pre appraised content

Appraise the Filter (pre-appraised content)

  • Criteria

    • Speed of updating

    • Scope and number of summaries

    • Summaries with graded evidence

    • Authors’ credentials, affiliations listed

      Developing and using a rubric for evaluating evidence-based medicine point-of-care tools. Journal of the Medical Library Association, Volume 99, No. 3, July 2011

      Speed of updating online evidence based point of care summaries: prospective cohort analysis. BMJ 2011;343:doi:10.1136/bmj.d5856 (Published 23 September 2011)

Levels of evidence

Levels of Evidence

Grade the quality of evidence based on the design of the clinical study

Variety of hierarchies in use

Existing knowledge can prevent

American Academy of Family Physicians Rating System

Level A

Systematic reviews of randomized controlled trials including meta-analyses

Good-quality randomized controlled trials

Level B

Good-quality nonrandomized clinical trials

Systematic reviews not in Level A

Lower-quality randomized controlled trials not in Level A

Other types of study: case control studies, clinical cohort studies, cross sectional studies, retrospective studies, and uncontrolled studies

Level C

Evidence-based consensus statements and expert guidelines



Appraisal required by user

Appraisal Required by User

Step 4

Step 4

  • Appraise best available evidence from original studies

  • If the other “S’s” don’t provide the answer, search for original studies

  • Use “clinical queries” limit in Ovid MEDLINE to speed retrieval

  • Least efficient (in terms of time) to answer clinical questions

Primary original studies

Primary (Original) Studies

  • Articles that report results of original research investigations

  • Conclusions supported by data and reproducible methodology

  • Require time to acquire and appraise

  • Good Source: MEDLINE (OVID)



  • Premiere biomedical database from the NLM (National Library of Medicine)

  • Covers 1950-present

  • Indexes >4000 international biomedical journals

  • Full text available for many articles

  • Ovid interface includes tools to quickly filter search results to specific study types

  • Access from http://library.nsuok.edu/collegeop/index.html

Ovid medline clinical queries

Ovid MEDLINE Clinical Queries

Step 5

Step 5

  • APPLY the evidence to patient care problems

    • Practice the EBM process in daily patient encounters

Steps to using ebm

Steps to “Using” EBM

  • Convert information need into answerable clinical question

  • Track down the best evidence to answer the question

  • Use the 4S approach to locate critically appraised content

Take home points

Take Home Points

  • Focused clinical question (PICO) reveals your search terms

  • Start your search at top of 4S hierarchy and work down

  • Be aware of the filter, i.e., levels of evidence, speed of updating

  • Look at more than one resource in the hierarchy. Findings may differ.

  • Practice makes perfect

Evidence based medicine lecture optometry 6111 research methodology

Evidence Based Medicine LectureOptometry 6111 Research Methodology

Sandra A. Martin, M.L.I.S.

Health Sciences Resource Coordinator

Instructor of Library Services

John Vaughan Library Room 305B

[email protected] – 918-444-3263

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