Cohg presentation for drf day
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  • In this presentation I intend to: Tell you something about Cochrane and what we do Talk about how we go about doing literature searches for systematic reviews (something which Trevor has asked me to look at with you) Do some group work on searching the literature (computer access)
  • Cochrane Collaboration, named after Archie Cochrane, an epidemiologist who called for systemic reviews of clinical trials in the 1970s. Lancet: The Cochrane Collaboration is an enterprise that rivals the Human Genome Project in its potential implications for modern medicine .“ What came out of this was the Cochrane Library, incorporating a database of systematic reviews and a central clinical trials register.
  • Cochrane itself consists of over 50 review groups worldwide, each with a different medical specialty, all producing systematic reviews for the Cochrane Library
  • Established in US in 1994, moved to Manchester in 1996
  • Over 700 authors based all over the world
  • These are some of the challenges for the future Pt 2 – At the moment we have a grant from the NHS which runs until 2015 as primary source of funding, but future is uncertain after that Pt 3 – particularly want to get consumers involved Pt 4 – Aim is to get results of the reviews into practice, many reviews are incorporated into guidelines Pt 5 – Reviews have to be updated every 2 years, maintaining this whilst publishing new reviews is a real challenge The solution of our co-ordinating editors Helen Worthington and Jan Clarkson was to develop a global alliance of professional and research bodies in dentistry which could help support us in our work
  • Global Alliance is now off the ground – here are some of the benefits for members The payoff will be to improve quality, to hopefully get more consumers (or patients) involved and enhanced product in podcasts and journal club material
  • So that’s some background to Cochrane, now we’re going to look at the second part of this session, which is how to search the literature systematically. This is my role for Cochrane. This is the foundation of a good systematic review, but also of a great research project in general, you need to be able to search the literature. The clearer the research question and concepts, the easier the search will be.
  • I believe you looked at Pico last year with Trevor? Here’s a reminder and some examples.
  • We don’t search for comparisons or outcomes. The comparison is often placebo or no treatment, so there’s no point. Outcomes may not appear in the abstract of a citation on a database, so searching for these could limit your search.
  • As a minimum… CINAHL – Oral hygiene for nursing home residents PsycINFO – dental anxiety, hypnosis
  • We’re going to look at the two methods for searching the literature via a database like MEDLINE – controlled vocabulary and free text.
  • MeSH are a series of subject headings, which allow you to search across articles on the same subject, which have been categorised and tagged with the headings.
  • Demo with dental caries. If you explode dental caries, it will also pick up those articles indexed with dental fissures and root caries
  • Dental caries AND chlorhexidine Dental caries OR dental decay Dental caries NOT root
  • This is an example of how a search comes together for PubMed. The first two lines are about alendronate. Line 1 is the MeSH heading. MH tells pubmed that this is a MeSH heading, and the noexp tells PubMed that we don’t want to explode the term. Line #2 is synonyms for Alendronate, or related terms. These are brought together in line #3, which tells pubmed you want to search for all of these terms. Lines #4-#6 cover the menopause, brought together by line 7. Again, line #4 is the MeSH, lines #6 and #7 are freetext. Note how they have been truncated, menopaus* will pick up menopause or menopausal. Lines #8 - #10 cover periodontal disease, again MeSH and related terms. Finally, we bring the search together in the final line - #3 (terms for alendonate), and #7 (terms for menopause) and #11, terms for periodontal disease. That constitutes a comprehensive search.

Transcript

  • 1. The Cochrane Collaboration and the Cochrane Oral Health Group Anne Littlewood Trials Search Co-ordinator [email_address]
  • 2. The Cochrane Collaboration
    • Established 1993 to respond to need for summaries of evidence in medicine and health
    • 28,000 people involved from over 100 countries
    • Cochrane Reviews are systematic reviews of primary research in human health care and health policy, and are internationally recognised as the highest standard in evidence-based health care .
    • http://www.cochrane.org
  • 3. The Cochrane Library
    • “ Every day someone, somewhere searches The Cochrane Library every second , reads an abstract every two seconds and downloads a full-text article every three seconds."
    • The Cochrane Library usage data 2009
    • The 2010 impact factor for CDSR is 6.187, in the top ten of healthcare journals worldwide
    • http://www.thecochranelibrary.com
  • 4. Cochrane Oral Health Group
    • International network of healthcare professionals, researchers and consumers preparing, maintaining, and disseminating systematic reviews of randomised controlled trials in oral health.
    • Oral health is broadly conceived to include the prevention, treatment and rehabilitation of oral, dental and craniofacial diseases and disorders.
  • 5. Cochrane Oral Health Group
    • 120 published reviews
    • 74 published protocols
    • 24 registered titles
    • Oral Health Group’s impact factor = 3.600
    • Third biggest journal impact factor in Dentistry after the Journal of Peridontology and the Journal of Dental Research
  • 6. Challenges
    • Maintain topic relevance and quality
    • Ensure infrastructure supports review process
    • Identify and reduce barriers to access
    • Encourage impact on practice
    • Update reviews
    • Global Alliance - invite international national and specialist groups
      • Professional
      • Research
  • 7. Benefits
    • Membership of GA Board
    • Decision making to identify important reviews
    • Group member to content expert group
    • Recognition of funding
    • Timely production of high quality important reviews
    • Consumer involvement
    • Enhanced products - podcasts, journal club
  • 8. Experience to date
    • Member organizations to date:
    • British Orthodontic Society
    • British Society of Paediatric Dentistry
    • New York University Dental School
    • Currently in negotiations with:
    • Australian Society of Prosthodontics
    • US Dental Specialty Groups
    • International Association of Dental Research
    • Other national and international dental organizations have been approached
  • 9. Cochrane Systematic Reviews
    • Well structured research question is the place to start: PICO
    • Once research question established, next stage is a systematic search of the literature
    • Makes sure all relevant studies included
    • Reduces the risk of bias
    • Ensures that others can replicate study
  • 10. PICO Participants eg children with caries, smokers with periodontal disease Intervention eg antibiotics, physiotherapy, powered toothbrushes Comparison What the intervention is to be compared to: eg another intervention, placebo Outcomes eg longevity of restorations, pain reduction, quality of life
  • 11. Searching for Studies
    • Take the first two elements of the research question:
      • Participants
      • Interventions
    • List as many synonyms for each as you can
    • Cochrane systematic reviews aim for MAXIMUM SENSITIVITY, to pick up ALL relevant RCTs
  • 12. Which databases?
    • MEDLINE
    • EMBASE
    • Cochrane Central Database of Controlled Trials
    • Other databases depending on topic:
      • CINAHL (Nursing)
      • PsycINFO (Psychology)
  • 13. Constructing a Search Strategy
    • Controlled vocabulary
      • MeSH and EMTREE
      • Hierarchy, broad concepts at the top, smaller concepts lower down the “tree”
    • Free text: words and phrases that can be found anywhere in the record
    • Cochrane Systematic Reviews use a combination of both techniques
  • 14. MeSH
    • The National Library of Medicine in the US has developed an indexing system: Medical Subject Headings (MeSH)
    • Subject headings are assigned according to the subject of an article by experienced indexers at the National Library of Medicine
    • MeSH can be “exploded” to include all the terms that are included in that subject heading on the tree
  • 15. How do I find the MeSH for my topic? Go to: http://www.nlm.nih.gov/mesh/MBrowser.html
  • 16. Free text searching
    • Searching for MeSH terms limits the search to only include those terms in the keyword field of a record
    • Free-text or keyword searching can be applied anywhere in the record – title, abstract, author, keywords or even full-text
    • You can add a single word, or a phrase: for example: “dental caries”
  • 17. Free text searching
    • Most freetext searches in databases work using Boolean operators:
      • AND, OR, NOT
      • AND is used when the article must contain both search terms
      • OR is used when a paper may contain either search term
      • NOT is used when the search should retrieve the first term and not the second
  • 18. Free text searching
    • Databases can support truncation or enable you to search for the stem of a word e.g.
    • PubMed:
      • child * will retrieve child , or children or child’s
    • Some databases also support wildcard searches e.g.
      • wom ? n will retrieve women or woman
    • Symbol for truncation / wildcard can vary
      • * or $ or ?
      • Use the help pages of databases to check symbol
  • 19. Example of a Cochrane Search
    • Alendronate for preventing periodontal disease in postmenopausal women
    • #1 Alendronate [mh:noexp]
    • #2 (Alendronate or biphosphonates or diphosphonates or clodronate or etidronate sodium or etidronate acid or residronate or risedronate or incadronate or tiludronate or ibandronate or medronate or pamidronate)
    • #3 #1 or #2
    • #4 Menopause [mh:noexp]
    • #5 (post-menopaus* or "post menopaus*" or postmenopaus*)
    • #6 (menopaus* or “elderly women” or osteoporo*)
    • #7 #4 or #5 or #6
    • #8 Periodontal Disease [mh:exp]
    • #9 periodont*
    • #10 ("furcation defect*" or "alveolar bone loss" or "gingival recession" or (teeth and loss) or (teeth and lost) or (teeth and lose) or (tooth and loss) or (tooth and lost) or (tooth and lose) or (tooth and mobil*) or (teeth and mobil*) or (tooth and extract*) or (dental and extract*) or (extract* and teeth))
    • #11 #8 or #9 or #10
    • #12 #3 and #7 and #11
  • 20. Exercise (20 mins)
    • Flossing for the prevention of dental caries
    • Participants: patients at risk of caries
    • Intervention: flossing
    • Construct a search: find the MeSH terms:
    • http://www.nlm.nih.gov/mesh/MBrowser.html
    • Think about what free text terms to add (synonyms for caries)
    • Test your search in PubMed: http://www.ncbi.nlm.nih.gov/pubmed/