KSOM Y2Evidence-Based Medicine: Background & Resources

Emily Brennan, MLIS ebrennan@usc.eduEileen Eandi, MLS eeandi@usc.eduJoe Pozdol, MLIS pozdol@usc.edu Evans Whitaker, MD, MLIS ewhitake@usc.edu

Norris Medical Library, Rm. 1022003 Zonal Ave.

Los Angeles, CA 90089-9130

Introduction• We are…

• Personal Librarians for KSOM Y2:

– Last Name: Ahn-Fecht Pamela CorleyFernandez-Lee Eileen EandiLeong-Penman Emily Brennan

(replacing Adrian Follette)

Perrin-Yasmeh Evans Whitaker

• Ask questions!• Please fill out evaluation forms at the end of class…

Context and Outline• Class today -- an extension of Dr. Samet’s lecture of August 7, 2009

• Assignment given today and posted on library student portal– Due date: August 28, 2009 to Curriculum Office

• Objectives of today’s session

I. EBM BackgroundA. Briefly review study types pertinent to EBMB. Introduce evidence pyramidC. Introduce levels of evidenceD. Introduce PICO and searchable clinical questions

II. EBM Resources A. Introduce major sources of evidence-based information at USC B. Provide search tips to promote maximally efficient searching

EBM BACKGROUND

EBM Defined• Simple concept

– Use the best available evidence to make clinical decisions…

• EBM process…

– Begins and ends with the patient

– Weighs 3 factors to make clinical decisions

• Best available clinical research

• Experience of individual clinician

• Patient preferences/characteristics

One Aspect of EBM

• “EBM encourages a healthy skepticism of every practice in medicine and promotes a culture of inquiry.”

– Sloane, P.D., Slatt, L.M., Ebell, M.H., Jacques, L.B., Smith, M.A. (2008). Essentials of family medicine (5th ed.). Philadelphia: Wolters, pp. 40.

Best available clinical evidence

Clinician experiencePatient needs,

desires, resources

Patient-Doctor Dyad – Not really changed through time

The point at which effecting Doctor-Patient communication and planning is informed by the best evidence

Three Interacting Realms of EBMThree Interacting Realms of EBM

Stages of EBM Process1. Formulate search (based on patient interaction)

2. Perform search

3. Assess search results • Relevance (does it apply to my patient?)• Validity (are the findings of the articles true?)

4. Apply results to your patient

5. Reassess your patient Repeat process as needed

You will see variations in the above depending on the author and the field in which they work

Study Types• Study types of most relevance to EBM

– Randomized Control Trial (primary literature)

• Participants are assigned randomly to treatment and control groups

• Groups are compared over time

– Systematic Review (secondary literature)

• Reproducible methods used to locate and select articles

• Inclusion/exclusion criteria

– Meta analysis (secondary literature)

• Numerical data from separate studies combined using statistical/mathematical methods

Evidence Pyramid

Source: http://library.downstate.edu/EBM2/2100.htm

Levels of Evidence (LOE)

• Another way to look at same idea…

• Confusing as…

– There are several systems

– None are universal

– All use a-d OR 1-5 OR some combination (e.g., 1a)

• Essential Evidence Plus collects some of these LOE systems

Levels of Evidence (LOE)

• Common finding in all LOE systems…

– Randomized controlled trial (RCT), Systematic review, Meta analysis are considered “best evidence”

• Reduce the chance of author bias…

• However…

– Many questions have little or no evidence…

• Use the best evidence that exists

• May mean case reports!

A Heart Failure Scenario• 65 yo male with history of hospitalization for congestive heart failure one year ago

beginning care with you today.

• Medications: diuretic , angiotensin converting enzyme (ACE) inhibitor, and a statin.

• Physical exam: BP of 124/78 in the right arm, sitting. His pulse is 85 and regular. His weight is 80 kg which he states is his normal weight. He has clear lung fields and no pretibial edema.

• You order lab work, a chest x ray, a resting oximetry, and an echocardiogram. – His lab work is all within normal limits. – His CXR show clear lung fields, borderline cardiomegaly, and flattened diaphragms. – His room air, resting oximetry is 95%.– His echocardiogram shows a mildly dilated left ventricle, an ejection fraction of

30%, and evidence of his previous myocardial injury.

• Your question: Should I start this patient with chronic CHF on beta blockers, specifically carvedilol?

Developing a Searchable Question

• Clinical question:

– “For a 65 yo man with congestive heart failure and systolic dysfunction, should carvedilol be prescribed?

– You might consider several outcomes (e.g., improved QOL, decreased hospitalization, decreased mortality)

• Searchable clinical question: – “Is carvedilol an effective treatment for congestive heart failure?”

• Concepts to use while searching for information:– Congestive heart failure, carvedilol

PICO• PICO – a structure used to formulate evidence-

based questions

– Example for today uses congestive heart failure

P Problem/Patient Congestive heart failure (CHF)

I Intervention Beta blocker (carvedilol)

C Comparison (optional) None (might consider metoprolol)

O Outcome Various things you might measure:--Quality of life--Mortality--Hospitalization--Cost

EBM INFORMATION RESOURCES

Background Resources

• Clinical Information Tools

– Essential Evidence Plus – ACP Pier– UpToDate– Clinical Evidence

EBM DatabasesFrom Ovid:

• Cochrane Database of Systematic Reviewso Mentioned by Dr. Sameto A collection of Systematic Reviews created by the Cochrane Collaboration

• ACP Journal Clubo Selected “original studies and systematic reviews”o “Warrant immediate attention by physicians” o What you see is an abstract of the article and commentary “by clinical experts”o Evaluate methodology and results

• Database of Abstracts of Reviews of Effects (DARE) o “DARE …systematically identifies and quality assesses reviews from around

the world.”

“Change database” and “Open and Re-execute” allow rapid search of all three sources

MEDLINE (OvidSP)

– MEDLINE with filters

• Systematic review “subject subset” • Meta analysis “limit”• RCT “limit”• Cohort “MeSH”• Case control “MeSH”

EBM Aggregator and Guidelines

– TRIPdatabase

– Sources of guidelines

• National Guideline Clearinghouse -- (US)

• National Institute for Health and Clinical Excellence (NICE) – (UK) – mentioned by Dr. Samet

Conclusion• We have touched on:

– the EBM process

– Evidence pyramid and Levels of Evidence

– PICO

– Places to find evidence-based information

• Background resources

• EBM databases

• MEDLINE with EBM “filters”

• TRIP and sources for guidelines

Last Slide

• All materials from this session will be posted on Year 2 KSOM library portal page

• Please fill out class evaluations

• Contact your personal librarian (or any of us) for questions about any of this

• Thanks!