“…conscientious, explicit and judicious use of the current best evidence in
making decisions about the care of individual patients…” -- Sackett, DL
FINDING THE BEST
EVIDENCE: AN OVERVIEW
OF THE RESOURCES
SPRING 2010
THIS SESSION WILL COVER
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What do we mean by evidence-based health care
Steps in practicing evidence-based care
Types of literature
Key resources for finding evidence-based
information
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THREE PRONGED APPROACH
The
Patient
Patient’s characteristics &
values
EBP!
Best
Evidence
Clinically relevant research,
the literature
Clinical
Expertise
Practitioner’s knowledge
& experience
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3
WHY USE AN EVIDENCE-BASED APPROACH?
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Need for current clinical information
Updates info in textbooks, journals, experts
Skills/experiences increase over time, current
knowledge may decrease
Increase in clinical research and literature
Conflicting clinical research [at times]
Limited time to find and evaluate research
4
STEPS IN PRACTICING EBP
1.
2.
3.
4.
5.
Convert need for information into focused clinical
question
Track down the best evidence
Critically appraise the evidence
Integrate evidence with clinical expertise and patient
values
Evaluate the process and adjust as needed
Evidence-based Medicine:
How to Practice and Teach EBM
By Straus SE, et al
Third Edition.
Churchill Livingstone: Edinburgh, 2005
0-443-07444-5, 299 pages.
Includes CD-ROM
5
Photo from CDC: Childhood overweight
CLINICAL SCENARIO
Your patient is a 14-yr
old boy with a weight
problem (obesity). He
has tried lifestyle
changes and
they have not been
effective, so he and his
parents ask you about other weight loss
options for an adolescent.
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USING THE LITERATURE IN PRACTICE
Background vs. Foreground questions
Background questions – getting up to speed on a topic.
General knowledge about a disorder. Look for info in textbooks,
summary material.
Foreground questions – specific knowledge about managing a
patient or disorder. Apply EBP techniques, use EBP resources
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BACKGROUND SOURCES
 UpToDate
 Clinical
Evidence
 MDConsult
 STAT!Ref
 MICROMEDEX
 Specialty texts via Ebling Library
website
 Harrisons
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EVIDENCE-BASED CLINICAL SUMMARY
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Medical topics in internal medicine (particularly strong), pediatrics,
ob/gyn and family medicine
Designed to provide a quick way to get up to speed
An updated version of UpToDate is released every four months
“What’s New” tab highlight changes with each major release.
For use in EBM is a mixed bag (use cautiously to answer clinical
questions (i.e. PICO questions)
Articles are a mixture of medical conclusions based on data from
studies and expert opinions of individual authors…not always clear
which statements are evidence-based and which are not
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USING THE LITERATURE IN PRACTICE
Background vs. Foreground questions
Background questions – general knowledge about a disorder.
Look for info in Reference sources
Foreground questions – specific knowledge about managing a
patient or disorder. Apply EBP techniques, use EBP resources
In a 14 year old obese male, how effective is the
drug Meridia for long term weight loss?
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1
0
CONVERT THE CLINICAL QUESTION TO PICO
P I C O helps to formulate the question
Patient/Population/Problem
Intervention
Comparison
Outcome
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CONVERT THE CLINICAL QUESTION TO PICO
P
I
In a 14 year old obese male,
how effective is the drug Meridia for
long term weight loss?
O
C – no comparison/placebo
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CREATING A SEARCH QUERY
P = In a 14 yo obese male
I = is Meridia
C=
O = effective and safe for long term weight loss?
P
obese
obesity
overweight
adolescent
adolescence
teen
teenager
youth
I
Meridia
sibutramine
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CREATING A SEARCH QUERY
P = In a 14 yo obese male
I = is Meridia
P
obese
obesity
overweight
I
adolescent
adolescence
teen
teenager
youth
Meridia
sibutramine
ORANGE = MeSH term
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CREATING A SEARCH QUERY
(adolescent OR adolescence OR teen OR teenager OR youth
OR child )
AND
(obese OR obesity OR overweight )
AND
(meridia OR sibutramine)
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
Place an “OR” between synonyms of the
same concept and surround concept terms with parentheses
Place an “AND” between concepts
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CREATING A SEARCH QUERY
(adolescent OR adolescence OR teen OR teenager OR youth OR
child) AND (obesity OR obese OR overweight) AND (meridia OR
sibutramine)
Use truncation character, if available:
(adolescen* OR teen* OR youth OR child) AND (obes* OR
overweight) AND (meridia OR sibutramine)
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STEPS IN PRACTICING EBP
1.
2.
3.
4.
5.
Convert need for information into focused clinical
question
Track down the best evidence
Critically appraise the evidence
Integrate evidence with clinical expertise and patient
values
Evaluate the process and adjust as needed
17
EVIDENCE HIERARCHY
high
Randomized control trials (RCTs)
Prospective cohort studies
Case-control (retrospective cohort) studies
Case studies
Opinion of authorities, editorials
Level of Evidence
Clinical summaries
Meta analyses/Systematic reviews
low
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EVIDENCE-BASED CLINICAL SUMMARY
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A compendium of short summaries of the current
state of the knowledge (and uncertainty) about
clinical conditions (prevention, treatment, and/or
diagnosis)
Entries are explicitly based on thorough searches
and appraisals of the literature and created from the
best available evidence from systematic reviews,
RCTs and observational studies
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EVIDENCE-BASED CLINICAL SUMMARIES
Examples:

BMJ Clinical Evidence

Essential Evidence Plus

UpToDate
http://clinicalevidence.bmj.com/
http://www.essentialevidence.com/
http://www.uptodate.com
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EVIDENCE-BASED CLINICAL SUMMARY
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Collection of brief reviews focusing on primary care and covering
over 3,000 clinical interventions with 570 clinical questions
answered.
Looks at current state of knowledge & ignorance about
prevention and treatment. Describes the best available evidence
and if there is no good evidence, it says so.
Each review focuses on single condition and is displayed in a
tabbed structure:
•
•
•
•
•
Single page summary of the review
Ranked list of interventions with discussion (benefits/harms)
Background info on the condition
A list of material published since the review search date
Links to major guidelines relevant to the review
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EVIDENCE HIERARCHY
high
Randomized control trials (RCTs)
Prospective cohort studies
Case-control (retrospective cohort) studies
Case studies
Opinion of authorities, editorials
Level of Evidence
Clinical summaries
Meta analyses/Systematic reviews
low
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SYSTEMATIC REVIEWS
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Summarize a particular topic by using explicit
methods to perform a thorough literature search
and critical appraisal of individual studies to identify
the valid and applicable evidence
Uses appropriate techniques to combine these valid
studies
Published in many journals and found in a variety of
other electronic sources
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SYSTEMATIC REVIEWS
Examples:

Cochrane Database of Systematic Reviews
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DARE
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TRIP Database

MEDLINE (PubMed)
http://www.cochrane.org/
http://www.crd.york.ac.uk/crdweb/
http://www.tripdatabase.com
http://www.pubmed.gov
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SYSTEMATIC REVIEWS
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5,600 systematic reviews and meta-analyses
Rigorous, highly-regarded, reviews
Focused on therapy/prevention, now covering diagnostic tests
Database includes protocols -- plans or sets of steps to be followed
in creating a systematic review
When searching within the Cochrane Library:
use the “Title, Abstract, Keywords” drop down to reduce irrelevant
records
Contains 15,000 reviews of systematic reviews.
Complements the CDSR -- quality-assesses and summarizes reviews that
have not yet been carried out by Cochrane
When searching within the Cochrane Library:
use the “The full review (Search All Text)” drop down to reduce irrelevant
records
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SYSTEMATIC REVIEWS
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Often overlooked secondary source for evidence on any type of
foreground question
Reviews the best original and review articles from over 100 of the
top clinical journals
If included, it is important!
Unlike DARE, clinical experts provide commentaries on the context,
methods, and clinical applications of the findings of each article
New interface
Includes only records/abstracts of journal articles (20 million)
Very current info (sometimes pre-pub)
Use MeSH terms for more efficient searching
Use Boolean operators (AND, OR)
Searching for systematic reviews:
• Use the “Find Systematic Reviews” box in Clinical Queries
OR Apply the Subsets limit “Systematic Reviews”
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SYSTEMATIC REVIEWS
15,000
# published per year
12,500
10,000
7500
5000
2500
1990
1995
2000
2005
2010
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SYSTEMATIC REVIEWS

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Many conditions, interventions,
diagnostic tools without good SRs
Need constant maintenance. Half will
need to be updated each year
Garbage in; garbage out
FAAT handout
http://www.cebm.net/index.aspx?o=1157
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EVIDENCE HIERARCHY
high
Randomized control trials (RCTs)
Prospective cohort studies
Case-control (retrospective cohort) studies
Case studies
Opinion of authorities, editorials
Level of Evidence
Studies
Clinical summaries
Meta analyses/Systematic reviews
low
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INDIVIDUAL STUDIES
Examples:
 MEDLINE
(PubMed)
http://www.pubmed.gov
 Google
Scholar
http://scholar.google.com

Other health databases
CINAHL
http://www.cinahl.com/
PsycINFO
http://www.apa.org/psycinfo/
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INDIVIDUAL STUDIES
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Includes only records/abstracts of journal articles (20 million)
Very current info (sometimes pre-pub)
Use MeSH terms for more efficient searching
Use Boolean operators (AND, OR)
Searching for single studies:
• Use the “Search by Clinical Study Category” box in CQ
• OR use the type of article limit: randomized controlled trials or
other appropriate level
Subset of larger Google: journal articles, technical reports, preprints,
theses, books and other documents and web pages deemed “scholarly”
Covers a great range of disciplines (strong in sciences and medicine)
It is particularly helpful for users who want:
• something good enough for the task at hand (not comprehensive)
• grey literature--sources outside of published journals
• info from sources across many disciplines
Limitations: rudimentary search features, lack of transparency of database
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content, uneven coverage (time and scope) and a delay in indexing
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GENERAL SEARCH HINTS
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Identify synonyms
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OR between synonyms
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Check MeSH database via PubMed
Use generic and trade names for drugs and tests
Use full names along with common abbreviations
OR between synonyms
Surround OR terms with parentheses
Enter concepts as separate sets AND between P, I,C
common cold AND (vitamin c OR ascorbic acid)
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STEPS IN PRACTICING EBP
1.
2.
3.
4.
5.
Converting need for information into focused
clinical question
Tracking down the best evidence
Critically appraising the evidence
Integrating evidence with clinical expertise and
patient values
Evaluating the process
33
CRITICALLY APPRAISING THE EVIDENCE

Centre for EBM (Toronto)
http://www.cebm.utoronto.ca

Centre for EBM (Oxford)
http://www.cebm.net

Users’ Guides series in JAMA
http://www.userguides.org
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Statistics Toolkit
By Perera R, et al
BMJ Books
2008
ISBN: 978-1-4051-6142-8
120 pages
35
STEPS IN PRACTICING EBP
1.
2.
3.
4.
5.
Converting need for information into focused
clinical question
Tracking down the best evidence
Critically appraising the evidence
Integrating evidence with clinical expertise and
patient values
Evaluating the process
36