Transcript EBM

Evidence-Based Medicine (EBM):
What does it really mean?
Presented by
Dr khamis Elessi BSc, MD,
MSc, DipAcu
Board in rehab. medicine

Ahmad, is a 40y/o patient referred to you as the
doctor in charge after seeing a neurologist and was
previously prescribed pregabalin 150 mg BID for the
treatment of spasticity.

Never heard of it? Now as doctor in charge, what do
you do?
1.
Prescribe another drug that you are familiar with?
Call the referring Doctor?
Call your Senior?
Search for the drug on the internet?
Just continue with the drug?
2.
3.
4.
5.
Traditional Sources of Medical
Information
 Internet
 Colleagues
/ Patients
 Conferences
 Drug Reps
 Textbooks
 Journals
Original “Official” Definition of EBM
“Evidence-based medicine is the
conscientious, explicit, & judicious
use of best available evidence in
making decisions about the care
of individual patients”
David Sackett, 1996
EBM Can improve:
 Medical
and Nursing care for Patient.
 Quality of Clinical Care
 Public Health in general
 Overall
goal is Improving the quality of
patients’ lives…
Principles of EBM
EBM has 2 fundamentals principles
1. Hierarchy of Evidence
2. Insufficiency of Evidence alone
Hierarchy of Evidence: Things to Consider

EBM is only as good as
the data available

A quality case-control
study is more meaningful
than a flawed RCT

Thus, systematic reviews
of RCTs are not
necessarily best evidence
Insufficiency of Evidence alone

Evidence is never enough alone but needs to
be coupled with clinical experience and patient
choices & values
 Evidence
 Expertise
 Expectation
Why is EBM important?
New types of evidence are being generated which
can create changes in the way patients are treated
Although evidence is needed on a daily basis,
usually physicians don’t get it due to
1.
Lack of time
2.
Out-of-date textbooks, and
3.
Disorganization of the up-to-date journals

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Too many articles are inconsistent, even contradictory
Most reviews are not systematic; instead are subjective
Why we Need to learn EBM
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There is big gap between research and practice
There are Wide variations in clinical practice
~40% of clinical decisions not supported by any strong
evidence
Many Ineffective treatments are adopted/maintained
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Pharmaceutical companies influence clinical decisions
Over-reliance on clinical experience & expert opinion
There are Concerns about cost & quality in medicine
To avoid medico-legal suits
Why bother with EBM?
The amount of information is growing exponentially,
but our attention is not.

The
low cost of production of poor quality information
results in high quality information being drowned out.

Too much information creates a poverty of attention.
The cost of finding specific information rises as the
amount of information increases.
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Too many journals/articles / no time to read
Review the World Literature Fortnightly*
*"Kill as Few Patients as Possible" - Oscar London
5,000?
per day
2000000
1,500
per
day
1500000
Medical Articles Per Year
Medical Articles per Year
2500000
1000000
95 per
day
500000
0
Biomedical
MEDLINE
Trials
Diagnostic?
A shocking news
 New
knowledge evolves very quickly.

Medical school knowledge quickly becomes
outdated and/or forgotten.

Half of what you are taught as medical students
will have been shown in ten years to be wrong.
And the trouble is none of your teachers know
which half,” said Dr. Sydney Burwell, Dean of
Harvard Medical school.
Sample of Information Retention
A study showed that about 50% read only 1 Hr/week
So, other half read more than 1 Hr/week
Examples of our ignorance of
Evidence
Corticosteroid for preterm Birth ( P5)
 Corneal Patching
 SIDS
 Arryhthmia suppression

 Ecainide/flecainide
(P6)
 Arrhythmia suppression
 RCT increased mortality
 Disease specific vs. patient specific outcomes
Patching corneal abrasion compared
with placebo
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The standard practice of both family physicians &
ophthalmologists has always been to patch the eyes
of patients with simple uncomplicated Corneal
abrasions as well as prescribing mydriatic agent and
antibiotics eye drops..
However, no one ever asked if patching was
beneficial, It was just common sense.
There has been at least 5 RCT’s of patch VS no patch
and each has come up with the same answer.
patches offer no benefit and may ever slow down the
healing process and increase patients discomfort.
Prevention of SIDS…”Back to Sleep”
Doctors I western countries traditionally
recommend that babies sleep on their
stomach.
 It was thought tat by sleeping on their back
infants at risk of regurgitation & aspiration
leading to SIDS.
 In 1980’s, some MD’s asked the question, is
there any evidence to support the practice
of sleeping infants on their stomach?.

Prevention of SIDS…”Back to
Sleep”
As it turn out case control & Ecological
studies found dramatic decrease among I
children who sleeps o their backs leading
to the national “Back to Sleep” program.
 Had some one asked the question 20
years earlier, tens of thousands of lives
might have been saved.

higher need for EBM !!!!

in 1994 17% of family Practitioners thought that
aspirin had no effect on the survival of patients
having an MI & stroke (evidence was available
from1988) .
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LBP & Disc Sx !!!!
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Many Variation in prescribing, diagnostic tests,
management of chronic conditions (DM, HTN).
How to apply EBM?
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It may be argued that MDs and other health care
providers have always used & continue to use
evidence, expertise & Px values in decision making.
•
This may be true for very good MDs. The difference
lies in emphasis, rigor and understanding.
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The 4 steps model for accessing, appraising evidence,
which make the process easy & more systematic.
•
It may help you refine some of the pre-EBM notions
and concepts you used to have.
Steps in Practicing EBM
1.
2.
3.
4.
Ask specific question to reach the required
information
Acquire the best available evidence with which
you can answer that question.
Critically Appraise that evidence for its
validity, impact, and applicability. → Decision
Apply the evidence with your clinical expertise
& patient’s preferences & values.
Clinical Questions
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Background - “What is it?”
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General information on a condition or disease
Foreground – “What do I do for this patient?”
Patient
 Intervention/Investigation
 Comparison Intervention/Investigation
 Outcome (Patient-Oriented)
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The ‘PICO’ principle
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Questions are often vaguely formulated, which makes
finding answers in the medical literature a challenge.
Properly structured question will make it easy to find
answers which is an essential first step in EBP.
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Most questions can be divided into four components:
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P =Population and clinical problem
I =Intervention or “exposure”(indicator or index)*
C =Comparator
O =Outcome (diagnosis/screening, prognosis, therapy,
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event, harm, or prevention)
How To Structure Clinical
Questions
P – Patient population / problem
What are you trying to address
Does gender/age influence clinical care
I - Intervention / Area of interest
What will you do for the patient?
Drugs, surgery, diet, exercise
C – Comparison intervention / status
Alternatives to your chosen intervention?
Against other interventions, gold standard, or no treatment
O – Measurable outcome of interest
What will be improved for the patient?
Less risk of fracture, fewer hospitalizations, etc.
Filtering the Evidence: The “Big Four”
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Diagnosis question
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Therapy question
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How well does it confirm or exclude a diagnosis?
Does it do more good than harm?
Etiology question
 How well does it identify a cause for a disease?
Prognosis question
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How well does it predict clinical course over time?
How To Structure Clinical Questions
Preferred design to answer different questions
Clinical Questions - “PICO”
Example 1:
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In a 5 year old child with conjunctivitis (patient) will
topical antibiotics (intervention) compared to no
treatment (comparison) lead to quicker symptom
relief (outcome)?
Example 2
Steps in Practicing “Pull” EBM
1.
2.
3.
4.
Ask specific question to reach the required
information
Acquire the best available evidence with which
you can answer that question.
Critically Appraise that evidence for its
validity, impact, and applicability. → Decision
Apply the evidence with your clinical expertise
& patient’s preferences & values.
Evidence Pyramid: Types of information
(Quality of Evidence)

Filtered Information
 Systematic Reviews/ Meta-Analyses
 Critically-Appraised Topics (Synthesis)
 Critically-Appraised Articles (Synopsis)

Unfiltered Information
 Randomized Controlled Trials
 Cohort Studies
 Case-Controlled Studies/Case Series and Reports
 Background
Info(Textbooks)/Expert Opinion
Steps in Practicing “Pull” EBM
1.
2.
3.
4.
Ask specific question to reach the required
information
Acquire the best available evidence with which
you can answer that question.
Critically Appraise that evidence for its
validity, impact, and applicability. → Decision
Apply the evidence with your clinical expertise
& patient’s preferences & values.
Step 3: Critically appraise the evidence (cont.)
There are 4 issues in critical appraisal:
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Relevance: refers to the extent to which the research
paper matches your needs.
Validity: is the extent to which the results are free
from bias. (selection Bias, Randomization,
Measurement bias, Analysis bias
Consistency: refers to the extent to which the results
are similar across different analysis in the study & are
in agreement with evidence from other studies
Importance & significance of Results ( analyzed in
light of type of Study
Step 3: Critically appraise the evidence (cont.)
Critique requires knowledge of basic epidemiology (study designs)
and biostatistics:
ASSUMING you have the right study design:
 Check appropriate sample size, randomization, treatment
allocation, analysis, etc.
 Sensitivity, specificity, prevalence, likelihood ratios
 Absolute risk reduction, relative risk reduction, odds ratios,
number needed to treat, numbers needed to harm.
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General Rule:
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Meta-analysis of RCT’s > RCT > Cohort > Case Control > Case
Series > Case Report.
Retrospective studies weaker than prospective studies
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Step 4: Steps in Practicing EBM
1.
2.
3.
4.
Ask specific question to reach the required
information
Acquire the best available evidence with which
you can answer that question.
Critically Appraise that evidence for its
validity, impact, and applicability. → Decision
Apply the evidence with your clinical expertise
& patient’s preferences & values.
Applying EBM helps you Make best
decisions in medicine
Making best practice decision
requires sound judgment
based on the integration of
best research evidence
 Clinical expertise
 Patient’s values

As
patient participates in care
decisions, you are practicing
TRUE evidence based
medicine
Final advises on EBM

Be ready to “surrender” to a better evidence when
found.
Do not become entrenched in what has been done for
years
A bad idea done by MANY for LONG time, still baddea
Not all claims to be “evidence based”, is really EBM
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Use High quality sources (Cochrane, AHRQ, ACP
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Journal Club, Clinical Evidence, InfoRetriever.
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Retrospective studies weaker than prospective studies
Discard Questionable results developed by poor
methodology