Evidence Based Review - IAPCOI by pptfiles

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									Evidence Based Review
   Introduction to Evidence Based Reviews

• Systematic reviews comprehensively examine the
  medical literature,
    – seeking to identify and synthesize all relevant information
    – formulate the best approach to diagnosis or treatment. Examples
      are many of the systematic reviews of the Cochrane
      Collaboration or BMJ's Clinical Evidence compendium.
• The best clinical review articles base the discussion on
  existing systematic reviews and meta-analyses,
    – incorporate all relevant research findings about the management
      of a given disorder.
    – provide readers with powerful summaries and sound clinical
      guidance.

Am Fam Physician 2002;65:251-8.
 Key Elements of Evidence Based Reviews

• Topic Selection
• Searching the Literature
• Patient-Oriented vs. Disease-Oriented
  Evidence
• Evaluating the Literature
• Levels of Evidence


Am Fam Physician 2002;65:251-8.
                             Topic Selection

• Choose a common clinical problem and avoid
  topics that are rarities or unusual manifestations
  of disease or that have curiosity value only.
• Whenever possible, choose common problems
  for which there is new information about
  diagnosis or treatment.
• Emphasize new information that, if valid, should
  prompt a change in clinical practice.



Am Fam Physician 2002;65:251-8.
                 Searching the Literature

•   When searching the literature on your topic, please consult several
    sources of evidence-based reviews
     – E.g Agency for Healthcare Research and Quality (AHRQ): Clinical Guidelines
       and Evidence Reports; American College of Physicians Journal Club (ACPJC);
       Bandolier; Centre for Evidence Based Medicine (CEBM); Clinical Evidence,BMJ
       Publishing Group; Cochrane Database of Systematic Reviews etc
•   In particular, try to find the answer in an authoritative compendium
    of evidence-based reviews, or at least try to find a meta-analysis or
    well-designed randomized controlled trial (RCT) to support it.
•   If none appears to be available, try to cite an authoritative
    consensus statement or clinical guideline.
•   If no strong evidence exists to support the conventional approach to
    managing a given clinical situation, point this out in the text,
    especially for key recommendations.

Am Fam Physician 2002;65:251-8.
    Patient-Oriented (POEM) vs. Disease-
          Oriented Evidence (DOE)

•   Concept of Patient-Oriented Evidence that Matters (POEM), in
    distinction to Disease-Oriented Evidence (DOE).
     – POEM deals with outcomes of importance to patients, such as changes
       in morbidity, mortality, or quality of life.
     – DOE deals with surrogate end points, such as changes in laboratory
       values or other measures of response.
     – Although the results of DOE sometimes parallel the results of POEM,
       they do not always correspond
•   When possible, use POEM-type evidence rather than DOE.
•   When DOE is the only guidance available, indicate that key clinical
    recommendations lack the support of outcomes evidence.


Am Fam Physician 2002;65:251-8.
                    Evaluating the Literature

•     Evaluate the strength and validity of the literature that supports the
      discussion
•     Look for meta-analyses, high-quality, randomized clinical trials with
      important outcomes (POEM), or well-designed, nonrandomized
      clinical trials, clinical cohort studies, or case-controlled studies with
      consistent findings.
•     In some cases, high-quality, historical, uncontrolled studies are
      appropriate (e.g., the evidence supporting the efficacy of
      Papanicolaou smear screening).
•     Avoid anecdotal reports or repeating the hearsay of conventional
      wisdom, which may not stand up to the scrutiny of scientific study
      (e.g., prescribing prolonged bed rest for low back pain).
•     Look for studies that describe patient populations that are likely to
      be seen in primary care rather than subspecialty referral populations.

    Am Fam Physician 2002;65:251-8.
                  Levels of Evidence




Am Fam Physician 2002;65:251-8.
    Systematic review and Meta-analysis

• Systematic review: Comprehensive literature
  search and critical appraisal of individual
  studies and uses appropriate statistical
  techniques to combine these valid studies.
• Meta-analysis: Studies with relevant data are
  identified. Eligibility criteria for inclusion and
  exclusion of the studies are defined. Data are
  abstracted. Abstracted data analyzed
  statistically
•   We undertook a systematic literature review with various search terms
    and hand searched online journals and scanned reference lists of
    identified citations. We restricted the search to Medline (Ovid), Embase,
    CINAHL, Global Health, Web of Science, WHOLIS, LILACS, IndMed,
    grey literature (SIGLE), and Chinese language databases and to studies
    published between Jan 1, 1995, and Oct 31, 2010. Panel 1 shows study
    eligibility criteria. No language or publication restrictions were applied.
•   Two authors (HN and VE) independently did the literature search and
    extracted data. Any disagreements were resolved after discussion. The
    Influenza Study Group agreed on a common approach to data analysis
    and formulated common case definitions. We invited participation of other
    researchers and contacted authors of published studies who had done
    similar population-based studies of paediatric influenza
• … systematic literature review with various search terms and
  hand searched online journals and scanned reference lists of
  identified citations. We restricted the search to Medline (Ovid),
  Embase, CINAHL, Global Health, Web of Science, WHOLIS,
  LILACS, IndMed, grey literature (SIGLE), and Chinese
  language databases and to studies published between 1995,
  and 2010. Panel 1 shows study eligibility criteria. No language
  or publication restrictions were applied.
• Two authors independently did the literature search and
  extracted data. Any disagreements were resolved after
  discussion. We invited participation of other researchers and
  contacted authors of published studies who had done similar
  population-based studies of paediatric influenza….
     Comments by Zambon M, Health Protection Agency,
                    London NW9 5HT, UK
      www.thelancet.com Published online November 11, 2011
                DOI:10.1016/S0140-6736(11)61262-2
• …. Nair and colleagues present a rigorous
  systematic review and meta-analysis of a surprisingly
  weak evidence base. The investigators assessed
  ..40 different studies between …with different
  methodologies …Unsurprisingly in view of the
  studies’ heterogeneity, estimates for global
  hospitalisation and for overall mortality owing to
  influenza in 2008 (28 000–111 500 deaths) in
  children younger than 5 years need elaborate
  statistical imputation…..

								
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