An introduction to EBM for health librarians


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Includes searching & teaching issues

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  • In a much-quoted 1996 editorial, David Sackett, an early and prolific author on evidence-based medicine, defined evidence-based medicine (EBM) as the “conscientious, explicit, andjudicious use of current best evidence in making decisions aboutthe care of individual patients.” (A) (italics added) This characterization highlights the three important parts of evidence-based medical practice: the patient, the evidence, and careful application of generalized evidence to the individual patient. (A) Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn't. BMJ. 1996 Jan 13;312(7023):71-2. PMID: 8555924 (
  • “Evidence-based medicine” was first introduced in the mainstream medical literature in a 1992 article, “Evidence-based medicine: A new approach to teaching the practice of medicine,” which presented EBM as “a fundamentally new approach” emphasizing “question formulation, searchand retrieval of the best available evidence, and critical appraisalof the study methods to ascertain the validity of results”. (B) A subsequent series of “Users' Guides to the Medical Literature” presented skills for searching for, appraising, and applying various types of published evidence to medical practice. As EBM gained prominence in the late 1990s and beyond, three streams of evidence dissemination developed: 1) systematic reviews gained increasing prominence in the medical literature, 2) knowledge search engines (including internet engines such as Google, and medline interfaces such as Ovid) became standard tools for medical literature searching, and 3) knowledge distillation and “push” services developed as a way to compile and disseminate concise reviews of evidence on specific topics or questions (eg, ACP Journal Club, InfoPoems, etc). (B)
  • (A) Evidence-Based Medicine Working Group. Evidence-based medicine. A new approach to teaching the practice of medicine. JAMA. 1992 Nov 4;268(17):2420-5. PMID: 1404801 ( Montori VM, Guyatt GH. Progress in evidence-based medicine. JAMA. 2008 Oct 15;300(15):1814-6. PMID: 18854545 (
  • Conceptually, evidence starts simply with what is observed. Every individual observation is an isolated piece of evidence. To generate higher quality evidence, however, it is important to compile, organize, and evaluate those individual observations in a systematic way. Thus, while an anecdotal observation constitutes evidence regarding a single event, a more organized compilation of several observed events can constitute a case series, a higher level of evidence. An even more organized way to evaluate an event or an intervention is to use systematic observation, as in an uncontrolled or controlled trial. A meta-analysis provides even higher quality evidence by systematically grouping together and synthesizing the results of multiple trials. Thus, the more systematic an approach that is taken to gathering and organizing evidence, ranging from the individual anecdote up to the meta-analysis of controlled trials, the higher quality the evidence. Since EBM advocates that medical decisions should proceed from application of the “current best evidence,” an appreciation of how to evaluate, or grade, evidence is crucial to the application of “best evidence” in practice.
  • An introduction to EBM for health librarians

    1. 1. “Health librarians & expert searching: emerging roles in an evidence-based era” Expert searcher, teacher …..OR a researcher ?? (will you aim to be one of these experts OR all three) Dean Giustini, UBC librarian / October 2014
    2. 2. What is evidence-based medicine? “…evidence-based medicine (EBM) is the conscientious, explicit & judicious use of current best evidence in making decisions about the care of individual patients” Sackett, et al. BMJ 1996;312:71-72 Dr. David Sackett
    3. 3. EBM – a glance back 20 years  Landmark article in 1992 JAMA Guyatt G, Cairns J, et al (McMaster University)  JAMA 1993 – 2000 “Users' Guides to the Medical Literature”  Last 15 years, three (3) trends ◦ Explosion of systematic reviews ◦ Rise of search engines e.g., Google Scholar ◦ Knowledge distillation & “push” / 2.0 services
    4. 4. EBM integrates evidence with care …evidence should always integrate with clinical expertise & preferences, values & circumstances of patients & families Patient Values/Local Conditions Best Evidence Clinical Expertise
    5. 5. Is it background …or foreground? • Background questions require use of background information • Foreground questions are asked by experts • Answers are found by searching the biomedical databases
    6. 6. Five Steps of EBM The five steps: Ask Access • Step 1 — Frame your clinical question • Step 2 — Find the “best evidence” • Step 3 — Critically appraise that evidence • Step 4 — Integrate best evidence into practice • Step 5 — Evaluate steps 1-4 Appraise Assess Apply
    7. 7. Use PICO to frame foreground Qs P = Patient Can you describe the patient or problem? I = Intervention What main intervention (or treatment) will be considered? C = Comparison Do you want a placebo comparison / or drug comparison? O = Outcome What is the desired outcome or effect for the patient?
    8. 8. Usefulness of medical information Is equal to: Relevance of information X validity Effort/work required Health librarians have two (2) options:  Find relevant information for physician (they determine its value)  Find authoritative sources that do the finding /validating for clinician
    9. 9. Hierarchy of Evidence MOST clinically relevant (at the top) Least clinically relevant (at the bottom) Tracking Down Filtered & Critically Appraised Expert Opinion / Not Filtered Background info
    10. 10. Validity/Strength of Inference Time Spent in Critical Appraisal Hierarchy of Evidence find evidence at level for clinician
    11. 11. Where is ALL the evidence? SYSTEMATIC REVIEWS • Cochrane Library via OvidSP • PubMed Clinical Queries / Haynes filters CLINICAL PRACTICE GUIDELINES • National Guideline Clearinghouse (US) • Canadian Medical Association Infobase RESEARCH CRITIQUES • ACP Journal Club 1996- • Bandolier 1994- & BestBETs EVIDENCE SUMMARIES • BMJ Clinical Evidence & FirstConsult • UpToDate META-SEARCH ENGINES • TRIP+ & SUMSearch
    12. 12. PICO frames the information need P = Patient, population or problem (Who is the patient or population of patients? What is the disease?) I = Intervention (What do you want to do with this patient e.g. treat, diagnose, observe?) C = Comparison intervention (What is the alternative to intervention e.g. placebo, different drug, nothing?) O = Outcome (What are the relevant outcomes (e.g. morbidity, mortality, death, complications)?
    13. 13. Why use PICO? • Defines a clinical scenario • Prepare you to search • Places focus on patient-centered questions • Developing a clinical question using PICO requires: • some background about the condition • some understanding the patient • outcomes & beliefs important to the patient • Prognosis – Disability? Quality of life? Cost? Improvement of symptoms?
    14. 14. EBM Reviews (meta-search) • Search via OvidSP • Includes all Cochrane topic reviews “Cochrane Library” • Includes clinical trials register • Articles reviewed in ACP Journal Club or BMJ Evidence-Based Medicine • Papers in Database of Abstracts of Reviews of Effectiveness (DARE) • Studies in DARE meet strict EBM scoring criteria Uses “Keywords” to search OvidSP’s EBMR UBC library access:
    15. 15. Cochrane Database of Systematic Reviews • Search via OvidSP • Independent non-for-profit international collaboration • Reviews are among studies of highest scientific evidence • Minimal bias: evidence included/excluded on basis of explicit criteria • Reviews involve exhaustive searching for studies & clinical trials, both published and unpublished • Abstracts are available for free; consumer summaries are free also UBC library access: Uses “Keywords” to search Cochrane …
    16. 16. Database of Abstracts of Reviews of Effects (DARE) • Search via OvidSP • Produced by the National Health Services' Centre for Reviews and Dissemination (NHS CRD) at the University of York, England • DARE is a full text database containing critical assessments of systematic reviews from a variety of medical journals • DARE contains structured abstracts of systematic reviews • Its records cover topics such as diagnosis, prevention, rehabilitation, screening, and treatment UBC library access:
    17. 17. ACP Journal Club • Search via OvidSP • Consists of two journals, ACP Journal Club (American College of Physicians) and Evidence-Based Medicine, by ACP & British Medical Journal • Editors select studies (includes reviews) that are methodologically sound and clinically relevant (high-quality) • Some topics may not be found • Review top clinical journals; top therapy, diagnosis, harm &prognosis Qs • Commentaries on each study's value • Helps physicians understand and apply evidence • Reveals changes in medical knowledge UBC library access:
    18. 18. Follow up files on HLWIKI Expert searching | Grey data ("hard to find" data) | Grey literature searching in medicine | Grey literature - part II Scoping reviews | Grey literature | Hand-searching |Snowballing