Concept of EBM by liaoqinmei


									    Introduction to EBM
Chavanant Sumanasrethakul MD.,MSc.
  Dept. of Preventive and Social Medicine
 BMA Medical College and Vajira Hospital
 ‘the conscientious, explicit and judicious use of
 current best evidence in making decisions about the
 care of the individual patient’

                 Sackett et al. Sao Paulo Med J. 1996; 114(3): 1190-1
Definition (2)
 ‘clinically relevant evidence, sometimes from basic
 science, but especially from patient-centred clinical
 research into the accuracy of diagnostic tests*, the
 power of prognostic markers*, and the efficacy &
 safety of interventions*’

                           Modified from Sackett et al. EBM 2nd Edition 2000

 * from clinical epidemiological studies
Fundamental principles of
1.   Clinical decision making

2.   A hierarchy evidence
Clinical decision making
   Evidence is never enough!!!

   Decision makers must always trade the benefits
    and risks, inconvenience, and costs associated
    with alternative management strategies, and in
    doing so consider the patient’s values
Level of evidence
            SR of RCTs
            RCTs
            SR of Cohort studies
            Cohort studies
            SR of Case-control studies
            Case-control studies
            Case-series
            Expert opinion
A hierarchy of strength of
evidence for treatment decision
A hierarchy of preprocessed
Studies              Preprocessing involves selecting only those studies that
                     are both highly relevant and characterized by study
                     designs that minimized bias and thus permit a high
                     strength of inference.
Systematic reviews   Systematic reviews provide clinicians with an overview
                     of all of the evidence addressing a focused clinical

Synopses             Synopses of individual studies or of systematic reviews
                     encapsulate the key methodologic details and results
                     required to apply the evidence to individual patient care.

Systems              Practice guidelines, clinical pathways, or evidence-
                     based textbook summaries of a clinical area provide the
                     clinician with much of the information needed to guide
                     the care of individual patients.

             Gordon Guyatt. Users’ guides to the medical literature. 2002
Why the interest in EBM?
1.   Need for valid information
2.   The inadequacy of traditional sources,
     too many journals and variable in
     research validity for practical use
3.   The disparity between our diagnostic
     skills and clinical judgments
4.   No time to read, too many patients, too
     many problems
Why don’t we use text book?
   Require an age to publish which some
    evidence maybe out of date
   Experts may have wrong information and
    may have conflict of idea for the same
Main factors of using EBM
1.   Individual clinical expertise
2.   Best external evidence
3.   Patient values and expectations
        Evidence of vitamin C in common cold patient

 Female university student,      Businessman, 40 years old,
  20 years old, had day-off        had a plan to negotiate
    from university and            profitable business and
 presented with first day of      presented with first day of
       common cold                      common cold

  Prefer to natural and non-    Prefer to recover as quick as
 chemical medication usage                 possible

  Not prescribe vitamin C            Prescribe vitamin C
   Why the treatment were different?

   Patient’s values and preferences were
    diverse depend on individual

   But it also had another factor  clinical
    expertise to find out the value expectation
    and willing of the patient
How do we actually practice
The 4 (5) steps of EBM
    Ask a focussed clinical question (exposure/cause,
     diagnosis, prognosis and treatment)
    Acquire / Search for appropriate epidemiological or
     research evidence to help answering the question
    Appraise (critically) the evidence (validity, impact,
    Apply / Synthesise the evidence with patient,
     clinical & policy issues; then apply (i.e. answer

    (Assess the quality of practical used)
Difficulty of EBM
   The most difficult part of EBM are searching
    the best evidence and appraise the evidence
   Clinician may use different method, such as
    appraised evidence from resources other
    than research studies
Other sources of evidence
   Cochrane library
   ACP
   Journal Club
   Best Evidence
   UpToDate
Who do you want to be?

                 Evidence generator

  ?                Evidence finder

                   Evidence user

                  Evidence ignorer

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