Transcript INTRODUCTION TO EVIDENCE BASE MEDICINE

INTRODUCTION TO
EVIDENCE BASED
MEDICINE
What is Evidence Based
Medicine
• Is the conscientious explicit and judicious
use of current best evidence in making
decision about the care of the individual
patient (Dr. David Sackett)
• It means integrating individual clinical
expertise with the best available external
clinical evidence from systematic
research.
• EBP is the integration of clinical
expertise, patient values, and the best
research evidence into the decision
making process for patient care
• Clinical expertise- the clinician’s
cumulated experience; education and
clinical skills
• The best evidence is usually found in
clinically relevant research that has
been conducted using sound
methodology.
Why Evidence Based
Practice/Medicine
• Explosion of Literature
Healthcare Literature with clinically
applicable findings is published at a rate that
is impossible for individual clinician to keep
up with
• Information needs
Practitioners information needs are not
being met.
For every three patients seen. Two
questions are generated
Only 30% of those questions are being
answered during visits
• Implementation Delays
Takes an average of 17yrs for clinical
research to be fully integrated into
everyday practice
The emerging discipline of translational
medicine or translational research seeks
to breech this divide.
• Evidence, by itself, does not make a
decision for you, but it can help support the
patient care process
• Integration of all the three components
enhances the opportunity for the best
clinical outcome and quality of life
• The practice of EBP is usually triggered by
patient encounters which generate
questions about the effects of therapy, the
utility of diagnostic tests, the prognosis of
diseases, or the etiology of disorders.
The Steps in the EBP Process
ASSESS
the patient
1. Start with the patient -- a clinical
problem or question arises from the care
of the patient
ASK
the question
2. Construct a well built clinical question
derived from the case
ACQUIRE
the evidence
3. Select the appropriate resource(s) and
conduct a search
APPRAISE
the evidence
4. Appraise that evidence for its validity
(closeness to the truth) and applicability
(usefulness in clinical practice)
APPLY:
talk with the patient
5. Return to the patient -- integrate that
evidence with clinical expertise, patient
preferences and apply it to practice
Self-evaluation
6. Evaluate your performance with this
patient
• EBM always begins and
ends with the patient
Clinical questioning in Evidence
Based Medicine
• Remember PICO – contains components of a
well focused question
• P = The patient or Problem
• I = Intervention, Prognostic Factors,
Exposure
• C = Comparison
• O = Outcomes
• After successfully formulating the
clinical question (step 1) you need
to find relevant evidence.
Hierarchy of Study Design
• Used to illustrate the evolution of the
literature.
• The base of the pyramid is where information
usually starts with an idea or laboratory
research.
• As these ideas turn into therapies and
diagnostic tools they are tested with
laboratory models, then in animals, and
finally in humans.
• The human testing may begin with volunteers
and go through several phases of clinical trials
before the therapy or diagnostic tool can be
authorized for use within the general
population.
• Controlled trials are then done to further test
the effectiveness and efficacy of a drug or
therapy. As you move up the pyramid the
amount of available literature decreases, but
increases in its relevance to the clinical
setting.
• Case series and Case reports consist of
collections of reports on the treatment of
individual patients or a report on a single
patient.
• Have little statistical validity. (use control
group)
• Case control studies are studies in which
patients who already have a specific
condition are compared with people who do
not have the condition
• Cohort studies take a large population who
are already taking a particular treatment or
have an exposure, follow them forward over
time, and then compare them for outcomes
with a similar group that has not been
affected by the treatment or exposure being
studied.
• Randomized, controlled clinical trials
introduce a treatment or exposure to study
its effect on real patients. They include
methodologies that reduce the potential for
bias (randomization and blinding) and that
allow for comparison between intervention
groups and control groups (no
intervention).
• Systematic Reviews focus on a clinical topic
and answer a specific question. An extensive
literature search is conducted to identify
studies with sound methodology
• Meta-analysis examine a number of valid
studies on a topic and combine the results
using accepted statistical methodology to
report the results as if it were one large study.
• The pyramid serves as a guideline to the
hierarchy of study design. You
may not always find the highest
level of study to answer your
question. In the absence of the
best evidence, you then need to
consider moving down the
pyramid.
Clinical Trials
• Clinical trial involves several
components:
• Pre- Clinical Trial - report of a preplanned clinical study of the safety,
efficacy and pharmacokinetic properties.
Non-human subjects(animals)
•Phase 0 – Pharmacokinetic and
pharmacokinetic properties. half life,
bioavailability. Small number of
volunteers(about 10)
• Phase 1- controlled clinical study of
the safety and efficacy of
diagnostic, therapeutic or
prophylactic drugs at different
dosages, based on a small number
of healthy persons and conducted
over the period of about one year.
About 100 people.
• Phase 2 - report based on several hundred
volunteers(up to 300), including a limited
number of patients, and conducted over a
period of about two years .Test of efficacy and
safety.
• Phase 3 - A large enough group of patients is
studied (up to 2000)and closely monitored by
physicians for adverse response to long-term
exposure, over a period of about three years
• Phase 4 - Post-marketing study of
diagnostic, therapeutic, or prophylactic
drugs, devices, or techniques that have
been approved for general sale after
clinical trials, phases I, II, and III.
• Cross-sectional studies describe the
relationship between diseases and other
factors at one point in time (usually) in a
defined population. Cross sectional
studies lack any information on timing of
exposure and outcome relationships and
include only prevalent cases.
• The practice of Evidence-Based
Practice advocates that
clinicians search the primary
literature to find answers to
their clinical questions
Medical Journals
• Journal of the American Medical
Association, JAMA
• The New England Journal of Medicine
• British Medical Journal
• PubMed/Medline
• Essential Evidence
• Clinical Evidence
• Journal Watch
Validity of a therapy
• 3 basic questions that need to be
answered for every type of study:
Are the results of the study valid?
What are the results?
Will the results help in caring for my
patient?