how to practice ebm - tzu chidlweb01.tzuchi.com.tw/dl/edu/cfd/doc/98slide/980822slide2_5.pdf · 2...
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How to practice EBM
• Ask an answerable clinical question • Search for evidence• Appraise the evidence• Translate into actions • Evaluate the performance
6Expert opinion, physiology, bench research
5[D]Case series4[C]Case-control study3b
Systemic review of case-control studies
3a‘Outcomes’ research2cCohort study or poor RCT2b
Systemic review of cohort studies
2a[B]‘All-or-none’1cSingle RCT1bSystemic review of RCTs1a[A]
TherapyLevel of Evidence
Grade of Recommendation
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Where and what to searchElectronic resources• PubMed• Textbooks• Journals• Official websites of academic organizations
or government agencies• Specialized databases for evidence-based
medicine• Filtered databases for evidence-based
medicine
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Example Specialized databases• Drug databases
– Micromedex• Travel advise
– CDC travel: http://wwwn.cdc.gov/travel/• Clinical guidelines
– National Guideline Clearinghouse™ (NGC) http://www.guideline.gov/
• Electronic textbooks– UpToDate
http://www.uptodate.com/home/index.html
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EBM ResourcesSystematic Literature Searches
• Cochrane Library (OVID)• Database of abstract of review of
effectiveness (DARE)
• Clinical Evidence
Systematic Literature Surveillance• ACP Journal Club (OVID)• National Guidelines Clearinghouse (AHRQ)• ClinicalTrials.gov
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The Cochrane library
• Cochrane Database of Systematic Reviews
• Database of Abstracts of Reviews of Effectiveness
• Cochrane Controlled Trials Register
• Cochrane Review Methodology Database
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ACP Journal Club• About 100 journals systematically
surveyed• Clinically relevant, highest-validity
articles abstracted• Structured abstracts to guide
critical appraisal• Clinical commentary
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Guidelines• Clinical Practice Guidelines may
be– Explicit evidence-based– Evidence-based– Opinion-based– “expert consensus”– National Guideline Clearinghouse™ (NGC)
http://www.guideline.gov/
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ClinicalTrials.gov• NIH, NLM, FDA sponsored• Database of clinical trials in progress• February 2000• Clinical trials need to be registered in
a public database order to get published in major journals
• US and CA – 80 countries
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PubMed• Freely available online since 1997at http://www.pubmed.gov
• Including MEDLINE and out of scope papers from MEDLINE journals
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Medline
• Acronym for Medical Literature Analysis and Retrieval System On-Line
• Computerized database of medical, dental, nursing and basic life science journals.
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Organization of PubMed Record
• Field tags– PMID– Title– Authors– Source– Abstract– Medical subject headings– Publication date– Language– Publication type
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Features of PubMed Services• Search box
– Limits– Preview/Index– History– clipboard– Details
• Display format and options– Summary– Abstract plus– Medline
• Related articles• Links• Clinical queries• My NCBI
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Features of PubMed Services• Search box
• Boolean operations of search terms ---capitalized words
– AND, OR, NOT– Works from left to right unless parentheses are used
– Limits– Preview/Index– History– clipboard– Details
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How MEDLINE Search works• Automatic term mapping
1. MeSH translation table2. Journal translation table3. Phrase list4. Author Index
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Medline Searching Strategies1. Free text and automatic term
mapping2. Title search3. Clinical queries4. Related articles5. Medical subject headings
• No strategy is perfect
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Search Strategy 1• To limit your search to useful evidence
first
• Add AND (“Cochrane Database SystRev”[journal] OR “ACP J Club” ”[journal])to the end of your search
• Boolean operations work from left to right unless parentheses are added
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Search Strategy 2• One very efficient searching
strategy is to use title search or clinical queries to quickly find one relevant article
• Use the Related articles and MeSHmethods for more exhaustive search