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

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

Learning Objectives

At the end of the presentation, you will be able to:• Define evidence-based medicine (EBM)• Understand the Five Steps to practice EBM• Use the 4S approach to organizing clinical research

evidence• Conduct an efficient online search to track down best

evidence• Access online and print tools to critically appraise the

evidence• Use the Five Steps for research and clinical care

www.cebm.net

“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.

Patient Concerns

Clinical Expertise

Best research evidence

EBM

What is EBM?

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 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

New Approach Required New Skills

Clinical question formulation Search and retrieval of best evidence Critical appraisal of study methods to ascertain validity of

results

Integration of EBM into medical school curricula patient-doctor courses

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” tool, that filters search results to specific study types and levels of evidence

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

EBM Process – 5 Steps

1. ASSESS: Recognize and prioritize important patient problems

2. ASK: Construct clinical questions that facilitate an efficient search

3. ACQUIRE: Track down the best evidence to answer the questions

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

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

4S Hierarchy

6S Hierarchy

4S Examples

Point of Care Summaries: Uptodate, Dynamed, FIRSTConsult

DARE (synopses of syntheses)

ACP Journal Club (synopses of studies)

Cochrane and other Systematic Reviews

Clinical Key Searches Limited to Study Types, MEDLINE Searches limited to 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

Evidence Based Retrieval

1. Find the answer that is supported by valid studies appropriate to the type of question and that is available in a timely manner.

2. Requires search terms plus best study design for question plus highest level of evidence

Extract search terms from question

Therapy/Prevention Question in PICO In patients with primary open angle glaucoma

or ocular hypertension [Patient/Population], do topical medications to reduce intraocular pressure [Intervention] versus no treatment [Comparison Intervention], delay visual field defect progression [Outcome]?

Possible Search Terms

Ocular hypertension, OHT, intraocular pressure, IOP, primary open angle glaucoma, POAG, medical treatment, medical intervention, visual fields, VF

As you move up the pyramid the amount of available literature decreases, but it increases in its relevance to the clinical setting.

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.

Best Study Design for Type of Question

Type of Question Study Design

Therapy/prevention Randomized controlled trials

Diagnosis Prospective cohort, blind comparison to a gold standard

Prognosis Cohort, Case Control, Case Series

Etiology/Harm Cohort, Case Control, Case Series

Systems/Summaries

• DynaMed– Summaries for more than 3,000 topics– Monitors >500 medical journals and

systematic review databases– Updated daily– Each article evaluated for clinical relevance

and scientific validity– Includes “graded evidence”

Glaucoma Summary

Evidence-based answer found in 1 minute, 39 seconds

Systems/Summaries• UptoDate

– Evidence based summaries of over 9,500 topics in over 20 specialties

– Ophthalmology not one of the specialties– Good for information on systemic conditions– Available through individual subscription.

Online access plus Mobile app for iPhone and iPad. Cost: $199 per year in training; $499 per year in practice

Syntheses

• Cochrane Database of Systematic Reviews (DSR)– Part of the Cochrane Library (1996)– 916 completed reviews, 1905 protocols– Among the highest level of evidence upon

which to base treatment decisions– Includes Dx since 2008– Eyes & Vision Research Group

• Contains over 165 reviews

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

Access full text of Cochrane reviews in OVID

Review found in 15 seconds

Cochrane DSR

Copyright: The Cochrane Library, Copyright 2009, The Cochrane Collaboration

Levels of Evidence

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

Variety of hierarchies in use

DynaMed

Levels of Evidence in Ovid based on AAFP SORT

Level A = “Specificity” in Ovid Clinical Queries Systematic reviews of randomized controlled trials including meta-

analyses Good-quality randomized controlled trials

Level B = “Sensitivity” in Ovid Clinical Queries 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

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 Sources: MEDLINE and Clinical

Key

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

search for original studies Appraise best available evidence or find

analysis in evidence based resource Use “clinical queries” limit in Ovid

MEDLINE Limit to “Study Type” in Clinical Key Least efficient (in terms of time)

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

Sandra A. Martin, M.L.I.S.Health Sciences Resource Coordinator

Instructor of Library ServicesJohn Vaughan Library Room 305B

marti004@nsuok.edu – 918-444-3263