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, learners will:• be able to define evidence based medicine

(also referred to as evidence based practice, evidence based eye care, etc.)

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

• understand the 4S approach to organizing medical evidence

What is EBM?

Evidence Based Medicine (EBM) is defined as the practice of medicine that ‘requires the integration of the best research evidence with our clinical expertise and our patient’s unique values and circumstances’.

Source: Straus SE, Richardson, WS, Glasziou P, Haynes RB. Evidence-Based Medicine: How to Practice and Teach EBM, 3rd ed. New York: Elsevier Churchill Livingstone, 2005.

Definitions

Best research evidence:• ‘Valid and clinically relevant research’.

Clinical expertise:• ‘Ability to use our clinical skills and past

experience to rapidly identify each patient’s unique health state and diagnosis, their individual risks and benefits of potential interventions, and their personal circumstances and expectations ‘.

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

New Skills

Efficient literature searching Evaluate the literature according to formal rules of

evidence

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

Steps to Practice EBM

1. Convert information need into answerable clinical question

2. Track down the best evidence to answer the question

3. Critically appraise the evidence for its validity (closeness to truth) , impact (size of the effect), and applicability (usefulness in practice)

4. Integrate appraisal with clinical expertise and with patient’s unique values and circumstances

Improvements in EBM Practice

1. Development of efficient search strategies to retrieve the evidence, e.g., clinical queries in Ovid MEDLINE

2. Creation of systematic reviews

3. Development of new clinical decision support tools

4. Future: Systems that integrate and summarize relevant research evidence about specific clinical problems and link through the EMR to a specific patient’s circumstances

“Using” EBM versus Doing EBM

Rapidly develop and practice EBM with limited time and resources

Use the 4S approach to locate critically appraised content

4S Hierarchy

Information Pyramid

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

Appraisal Required by User

Steps to Using EBM

1. Convert information need into answerable clinical question

2. Track down the best evidence to answer the question

3. Use the 4S approach to locate critically appraised content

Is the Evidence Available?

For many common, clinical issues in Optometry and Ophthalmology, there are few acceptable sources to guide decision making

Implementation of evidence-based practice in optometry, p. 240

Using EBM – Step 1

Frame the well built clinical question Arises from the clinical encounter Used to initiate search for evidence

Four basic types of clinical questions Therapy/prevention Diagnosis Etiology Prognosis

Selecting the Question

Begin with the patient encounter Which question

is most important to the patient’s well being fills gaps in your clinical knowledge is feasible to answer in the time available

Foreground 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 Question

In patients with open angle glaucoma (POAG), does IOP lowering treatment (medical or surgical) versus no treatment delay visual field loss?

Search Terms

Therapy Question In patients with open angle glaucoma

(POAG) [Patient/Population], does IOP (intraocular pressure) lowering treatment (medical or surgical) [Intervention] versus no treatment [Comparison Intervention], delay visual field loss [Outcome]?

Search Terms: open angle glaucoma, POAG, IOP, intraocular pressure, visual field loss

Type of question leads to type of study to best answer the question

Type of Question Type of Studies

Therapy Select treatments that do more good than harm, worth the effort and costs

Diagnosis Select and interpret diagnostic tests against the gold standard

Prognosis Estimate the patient’s clinical course

Etiology/Harm Identify causes and risk factors

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.

Evidence Pyramid

Number of studies fewer at higher levels of the pyramid, but of higher quality and relevance to clinical practice

Best Study Design for Type of Question

Type of Question Study Design

Therapy 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

Using EBM – Steps 2 & 3

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

Critically Appraised Content

Systems

• Dynamed– Summaries for more than 3000 topics– Monitors >500 medical journals and

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

and scientific validity

Databases

Databases

1:39

Synopses

• A step down from Systems• Useful when no answer can be found in

the Systems• Summary of individual studies and reviews• Faster than reviewing the individual

studies• Examples: ACP Journal Club, Evidence

Based Ophthalmology

Synopses

• ACP Journal Club– 1991-2009 archive of cumulative content– Periodically thinned– Selected from >100 journals– Published monthly– “Structured abstracts”, critically appraised– Commentaries on context, methods, and

clinical applications by expert clinicians– IM focus (Tx, Px, Harm, and Dx)

ACP Journal Club

Synopses

• Evidence Based Ophthalmology– Quarterly journal includes reviews of 24

critically relevant articles from ocular literature– Editorial board comprised of practicing

physicians with expertise in epidemiology and clinical trials

– Search NSU Journals@Ovid

Evidence Based Ophthalmology

Syntheses

• Systematic reviews• Supplement Synopses with more detail• Compare findings• Cochrane Database of Systematic

Reviews is the premiere example

Syntheses

• Cochrane Database of Systematic Reviews– 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 136 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 through OVID

Cochrane Database

:15

Syntheses• All Evidence Based Medicine Reviews

– Database of seven EBM Resources• ACP Journal Club (synopsis)• Database of Abstracts of Reviews of Effects

(DARE) (synthesis)• Cochrane Database of Systematic Reviews

(synthesis)

– Access through Ovid– Expands search for summaries/reviews

Appraisal Required by User

Original Studies• Synopses and syntheses take 6 months to

years to appear• If the other “S’s” don’t provide the answer,

search for studies• Must critically appraise the evidence

yourself. Understand and apply measures of internal/external validity

• Least efficient (in terms of time) for clinical questions

Primary (Original) Studies

• Articles that report results of original research investigations

• Conclusions supported by data and reproducible methodology

• Good Source: MEDLINE (OVID)

Databases

• MEDLINE– Premiere biomedical database from the NLM

(National Library of Medicine)– Covers 1950-present– Indexes >4000 international biomedical

journals– Full text available for many articles– Access through Ovid

MEDLINE Indexing

Search Query

Boolean Connectors

MEDLINE Search Limits

• Limit search results to study type– Randomized controlled trials– Clinical trials

• In OVID, limit by “Clinical Queries” • Appraise study for validity and relevance

Ovid MEDLINE Clinical Queries

Levels of Evidence

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

• Variety of hierarchies in use

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

Dynamed

Take Home Points

Foreground question (PICO) reveals your search terms

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

Be aware of the filter Look at more than one resource in the

hierarchy. Findings may differ. Practice makes perfect

Evidence Based Medicine LectureNSUOCO Residency Journal Club

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

Optometry Subject LibrarianJohn Vaughan Library Room 305B

marti004@nsuok.edu – 918-444-3263