Transcript Concept of EBM

Introduction to EBM
Chavanant Sumanasrethakul MD.,MSc.
Dept. of Preventive and Social Medicine
BMA Medical College and Vajira Hospital
Definition
‘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
EBM
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
evidence
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
question.
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 evidencebased 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.
2.
3.
4.
Need for valid information
The inadequacy of traditional sources,
too many journals and variable in
research validity for practical use
The disparity between our diagnostic
skills and clinical judgments
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evidence maybe out of date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
situation
Main factors of using EBM
1.
2.
3.
Individual clinical expertise
Best external evidence
Patient values and expectations
Example
Evidence of vitamin C in common cold patient
Female university student,
20 years old, had day-off
from university and
presented with first day of
common cold
Businessman, 40 years old,
had a plan to negotiate
profitable business and
presented with first day of
common cold
Prefer to natural and nonchemical medication usage
Prefer to recover as quick as
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
EBM?
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,
precision)
Apply / Synthesise the evidence with patient,
clinical & policy issues; then apply (i.e. answer
question)
(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