in Evidence-biased Medicine

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in Evidence-biased Medicine
Literature Search

• ??.??. ?????? ???????????

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Aims of Literature Search

• To solve clinical problems (EBM)
• To search for existing knowledge in order to
  conduct a research
• To update knowledge

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5A of Evidence-Based Practice
ASSESS problem
ASK the right question
Professional experience Pathophysiology Pharmacolo
gy Psychology Organizational issues Costs Politics
etc
ACQUIRE search for the best available evidence
APPRAISE the evidence
ASSESS
Decision making
APPLY
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General Search Strategy
Search the best available database
Define relevant, searchable terms
Design search strategy
No
Relevant results?
Yes
Summarize Appraise the evidence
Poor
GOOD
Apply the evidence
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Well-built Clinical Question PICO

• P Patients or population
• I Intervention
• C Comparison
• O Outcome
• Type of question
• Therapy, etiology, prognosis, diagnosis, etc.
• Study design
• Descriptive, case-control, RCT, etc.

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Example

• ??????????????????????????????? diabetic
  nephropathy ???????????????? ESRD ??????????????
  ????????????????????? ACEI ??????? ARB
  ???????????????????????????? ACEI ???????????????

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Formulate the question

• Patients children with diabetic nephropathy
• Intervention ACEIARB
• Comparison ACEI
• Outcome ESRD
• Question therapy
• Design systematic review, RCT

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Tools

• Hardware
• A computer with (good fast) online access
• LAN, MODEM (ADSL, cable)
• Software
• Web browser
• Internet Explorer, FireFox, Opera
• Adobe Reader (latest version from adobe.com)
• Reference management softwares
• EndNote, ProCite, Reference Manager
• Electronic databases
• On-line
• Off-li

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Medical Clinical Evidence Sources

• Expert
• Standard textbooks
• Teaching documents
• Meeting presentation
• Proceedings of presentation
• Thesis
• Current contents

• References
• References of the references
• Index books
• Science citation index
• Index medicus (1879)
• Excerpta medica (1948)
• Electronic databases

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Search Exhaustively

• Electronic databases
• Printed journals, hand-search
• Unpublished articles
• Expert seeking
• Pharmaceutical companies data
• Grey literature
• General internet search engines google, yahoo,
  msn, altavista, itools

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Internet Search Engines

• General
• - Google
• - Yahoo
• - MSN
• - Live
• - Altavista
• - Excite
• - HotBot
• - Lycos
• - Go.com
• - Ask.com

• Special search engine
• - Clusty.com
• - Kartoo.net
• Metasearch engines
• - Gahooyoogle.com
• (search Yahoo,
• Google,all at once)
• - Arrowsearch.net
• - Copernic Agent

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Electronic Databases
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Electronic Databases

• Bibliographic databases
• Medline
• Embase
• Scopus
• Science Citation Index
• LILACS
• Open access databases
• Grey literature databases
• Web search engines
• Google Scholar
• Scirus

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Bibliographic Database

• Medline
• About 5,000 journals
• Free access via PubMed
• http//www.ncbi.nlm.nih.gov/pubmed/
• Now include Oldmedline
• Oldest article in 1865 Trans Am Ophthalmol Soc
• PubMed Central (http//www.ncbi.nlm.nih.gov/pmc/)
  
• Free full-text
• Mostly articles in English from North American
  region

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Bibliographic Databases (Thai)

• Siriraj Thai Medical Index (http//www.medlib.si.
  mahidol.ac.th/)
• Chula Thai Index Medicus (http//www.library.md.c
  hula.ac.th/)
• Other Thai databases
• ????????????????????????????????????????????
  (http//www.stks.or.th/web/)
• ???????????????? ???????????????????????????????
  (http//www.riclib.nrct.go.th/)

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Bibliographic Databases (Thai)

• Thai journal pointer
• Journal Link (www.journallink.or.th)
• Thai journal citation index center (TCI)
• (www.kmutt.ac.th/jif/public_html/)

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Pre-filtered Clinical Resources

• Cochrane library
• Online access http//www.thecochranelibrary.com/v
  iew/0/index.html
• Offline access CD updated quarterly
• ACP Journal Club (previous Best Evidence)
• www.acpjc.org
• Clinical Evidence
• www.clinicalevidence.com
• Evidence-based Medicine (EBM Online)
• http//ebm.bmj.com/

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Pre-filtered Clinical Resources

• UpToDate
• www.uptodate.com
• CD updated every 4 months

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Multidisciplinary Clinical Resources

• Ovid.com
• MDConsult.com
• Full-text of Clinics of North America Journals
• Full-text of Year Books
• Not all have pdf files

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Electronic Text Books

• Harrison Online
• www.harrisonsonline.com
• www.harrisonsmed.com (store)

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PubMed
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What is PubMed?

• A web-based retrieval system developed by NCBI (a
  part of Entrez retrieval system)
• Free version of MEDLINE on the web

NIH
National Institutes of Health
NLM
National Library of Medicine
National Center for Biotechnology Information
NCBI
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PubMed Database

• A database of bibliographic information drawn
  primarily from the life sciences literature
• PubMed contains links to
• Full-text articles at participating publishers'
  Web sites
• Other third party sites such as libraries and
  sequencing centers
• All citations in MEDLINE are assigned MeSH Terms
  and Publication Types from NLM's controlled
  vocabulary.

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What Does MEDLINE Cover?

• Not only medicine
• medicine
• nursing
• dentistry
• veterinary medicine
• health care system
• preclinical sciences e.g., molecular biology

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How Big is MEDLINE?

• gt 5,000 biomedical journals
• gt 16 million citations back to 1865
• Published in the U.S. and 70 other countries.
• Coverage is worldwide, but most records are from
  English-language sources or have English
  abstracts
• MEDLINE contains citations, not full-text
  articles (PubMed provides links to full-text)

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Searching PubMed
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A basic search

• Identify the key concepts for your search.
• Example Find citations about bronchodilators for
  treating asthma in children.
• The key concepts are bronchodilators, asthma and
  children
• Enter terms into the search box.
• Press the Enter key or click Search.

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Combining search terms with Boolean operators

• AND retrieves results that include all the search
  terms.
• OR retrieves results that include at least one of
  the search terms.
• NOT excludes the retrieval of terms from your
  search.

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Combining search terms with Boolean operators

• Examples
• Find citations on DNA that were authored by Dr.
  Crick in 1993 dna mh AND crick au AND 1993
  dp
• Find citations on the effects of heat or humidity
  on multiple sclerosis (heat OR humidity) AND
  multiple sclerosis
• Find citations about arthritis excluding the
  Publication Type Letter arthritis NOT letter pt

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Automatic term mapping (ATM)

• Untagged terms that are entered in the search box
  are matched (in this order) against
• MeSH (Medical Subject Headings) translation table
  
• Journals translation table
• Full Author translation table
• Author index
• Full Investigator (Collaborator) translation
  table
• Investigator (Collaborator) index

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Automatic term mapping (ATM)

• To bypass ATM, using the following formats
• Enclose the phrase in double quotes kidney
  allograft
• Use a search tag kidney allografttw
• Use a hyphen first-line
• Truncate kidney allograft

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Truncating search terms

• Example flavor
• Finds terms that begin with the root term flavor,
  such as flavored, flavorful, flavoring, etc.

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MeSH

• NLM's controlled vocabulary thesaurus.
• Terms naming descriptors in a hierarchical
  structure that permits searching at various
  levels of specificity.

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Example of MeSH
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Example of MeSH
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Example of MeSH
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Search Field Descriptions and Tags
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Search Field Descriptions and Tags

• Example
• Search for articles about influenza published in
  the New England Journal of Medicine
• influenza mh AND n engl j med ta

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Searching by author

• Enter the authors name in the format of last
  name followed by initials. Omit punctuation.
• Examples smith ja jones k
• If only the author's last name is entered, tag
  the name with the author search field au
• Full author names may be searched for citations
  published from 2002

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Searching by journal title

• Enter in the search box one of the following
• full journal title (e.g., molecular biology of
  the cell)
• title abbreviation (e.g., mol biol cell)
• To find full journal names, use the Journals
  database
• Use the Single Citation Matcher
  (http//www.ncbi.nlm.nih.gov/corehtml/query/static
  /citmatch.html )

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Limits

• by dates, type of article, languages, species,
  gender, subsets, ages, text options, and specific
  search fields.
• http//www.ncbi.nlm.nih.gov/pubmed/

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Combining searches using History

• Previous searches can be combined or used in
  subsequent searches
• http//www.ncbi.nlm.nih.gov/pubmed/

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PubMed Results
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Summary Display
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Abstract Display
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Medline Display
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??????????? file ??????????? medline
????????????????????????? reference manager
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??????????? article ??????????????
???????????????? clipboard
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Search Strategy Tips

• Identify the key concepts.
• Determine alternative terms for these concepts,
  if needed.
• Refine your search to dates, study groups, etc.,
  as appropriate.
• Practice helps. Strategies and styles will differ
  according to personal choice and professional
  discipline.

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• ??????????? 5 ????? ????????? UTI ????????????
  ?????????????????? phimosis ?? imaging studies
  ???????? ???????????????????????? steroid cream
  ????????????????????? ?????????????????????

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• Patients infants with phimosis
• Intervention circumcision
• Comparison no circumcision
• Outcome Urinary tract infection
• Question therapy
• Design systematic review, RCT

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• Patients infants with phimosis
• Intervention steroid
• Comparison no intervention
• Outcome retractable prepuce
• Question therapy
• Design systematic review, RCT