Transcript EBM- Final Abdulmonem

EVIDENCE BASED MEDICINE
A new approach to clinical care and research
OBJECTIVES OF THE SESSION
• Recognize the concepts and
principles of EBM.
• Identify the important of EBM
as an essential part of clinical
practice.
• Discuss the Skills needed for
EBM practice.
• Recall the five steps approach
to EBM practice.
• Identify the application of
EBM in clinical practice.
• Discuss the barriers to practice
EBM
• Provide some examples of
EBM practice
Pause for Thought
For three minutes
• Why this session is important?
• What is EBM
• What are the
• Benefits ??
First alone then 2-3 in group
a test…1st ?
WHAT IS THE BASIS OF YOUR
MEDICAL PRACTICE?
(Check all that apply)
A.
Training, clinical experience and consultation
with other professionals
B.
Convincing evidence (non-experimental) from
articles, case reports, product literature, etc.
C.
Preferences of the patient
D.
Active search of Randomized Controlled Trials,
Systematic Reviews, Meta-Analysis Reports
WHAT IS THE BASIS OF YOUR
MEDICAL PRACTICE?
EXCELLLENT!
A.
Training, clinical experience and consultation
with other professionals
B.
Convincing evidence (non-experimental) from
articles, case reports, product literature, etc.
C.
Preferences of the patient
D.
Active search of Randomized Controlled Trials,
Systematic Reviews, Meta-Analysis Reports
BUT… Past knowledge and practice
might be outdated or inadequate
Graduate Medical School
Practiced Physician
WHAT IS THE BASIS OF YOUR
MEDICAL PRACTICE?
FANTASTIC!
A.
Training, clinical experience and consultation with
other professionals
B.
Convincing evidence (non-experimental) from articles,
case reports, product literature, etc.
C.
Preferences of the patient
D.
Active search of Randomized Controlled Trials,
Systematic Reviews, Meta-Analysis reports
BUT… This evidence may be biased, outdated,
incorrect, or not applicable to your patient
JOURNALS (1987 to present)
ARTICLES
ADVERTISEMENTS
WHAT IS THE BASIS OF YOUR
MEDICAL PRACTICE?
WONDERFUL!
A.
Training, clinical experience and consultation with other
professionals
B.
Convincing evidence (non-experimental) from articles,
case reports, product literature, etc.
Mutual Respect +
Shared Goals =
Better Cooperation
and Compliance
C.
Preferences of the patient
D.
Active search of Randomized Controlled Trials,
Systematic Reviews, Meta-Analysis reports
The patient should be involved in
all important decisions
But this is NOT always an easy task!
And conflicts WILL occur!
No salt?
Lose weight?
Forget it!
Just give me a pill!
I WON’T take that medicine…
The side effects are
INTOLERABLE!
But doctor, I DO want
to have children!
And conflicts WILL occur!
No salt?
Lose weight?
Forget it!
Just give me a pill!
I WON’T take that medicine…
The side effects are
INTOLERABLE!
But doctor, I DO want
to have children!
Education about current alternatives and risks is often
needed… for both the Patient and the Doctor!
Wow…
I never knew that high
blood pressure could
be so dangerous at my
age!
Yes, I’d like to try that
new medication!
I’ll discuss those risks
with my husband.
Education about current alternatives and risks is often
needed… for both the Patient and the Doctor!
An important rule in Evidence Based Medicine…
It STARTS with the patient and ENDS with the patient.
The patient’s preferences MUST be considered!
WHAT IS THE BASIS OF YOUR MEDICAL
PRACTICE?
WOW!!! SUPERB!!!
A.
Training, clinical experience and consultation with other
professionals
B.
Convincing evidence (non-experimental) from articles,
case reports, product literature, etc.
C.
Preferences of the patient
D.
Active search of Randomized Controlled Trials,
Systematic Reviews, Meta-Analysis reports
In the practice of Evidence Based Medicine,
it is the physician’s duty to find the best and
most current information and apply it
judiciously for the benefit of the patient.
But… A practice based exclusively on science and math
is effective only if your patients are robots or clones!
Don’t forget to allow for individual human differences
and personal preferences!
WHAT IS THE BASIS OF YOUR
MEDICAL PRACTICE?
If you checked all 4 items…
A.
Training, clinical experience and consultation with other
professionals
B.
Convincing evidence (non-experimental) from articles,
case reports, product literature, etc.
C.
Preferences of the patient
D.
Active search of Randomized Controlled Trials,
Systematic Reviews, Meta-Analysis reports
CONGRATULATIONS!
You are practicing
EVIDENCE BASED
MEDICINE!
A.
Training, clinical experience and consultation with other
professionals
B.
Convincing evidence (non-experimental) from articles, case reports,
product literature, etc.
C.
Preferences of the patient
D.
Active search of Randomized Controlled Trials, Systematic
Reviews, Meta-Analysis reports
EVIDENCE BASED MEDICINE
A new approach to clinical care and research
1.
2.
3.
4.
5.
6.
Definition of EBM
Basic Steps
Trials, Studies and Reports
Pros, Cons and Limitations
EBM Library
Advanced EBM
“What is Evidence Based Medicine?”
“And where did it come from?”
A BRIEF HISTORY
1980’s: McMasters University in Ontario, Canada
Dr. David Sackett and colleagues proposed Evidence
Based Medicine (EBM) as a new way of teaching, learning
and practicing medicine.
Dr. Sackett defines EBM as:
“…The conscientious, explicit, and judicious use
of current best evidence in making decisions
about the care of individual patients.”
• "Evidence-based medicine is the
integration of best research evidence
with clinical expertise and patient
values."
Sackett, D. L. (2000). Evidence-based medicine: How to practice and
teach EBM(2nd ed.). Edinburgh; New York: Churchill Livingstone.
• Clinical expertise: the clinician’s cumulated
experience, education, and clinical skills
• Patient values: The patient brings to the
encounter his or her own personal and unique
concerns, expectations, and values.
• Best Research Evidence: usually found in
clinically relevant research that has been
conducted using sound methodology
Evidence Based Medicine
It is a change in the way physicians practice medicine, teach and
learn, and handle research.
Clinical practice: Based on the best current evidence
(not necessarily on how it’s always been done)
Patient Care: Compassionate, patient-oriented
(less authoritarian)
Learning & Teaching: Problem-based, problem-solving
more investigative, less know-it-all-by-yesterday
Research: More stringent approach, better proof criteria
(more demanding of proof, less room for error)
THREE MAJOR
COMPONENTS of
EBM
PATIENT
Question
or
Problem
PHYSICIAN
INFORMATION
THE ADDED DETAILS
PATIENT
Values, Concerns Preferences,
Expectations
Life predicament
EBM
PHYSICIAN
Training & Experience
Current Expertise
Continued learning
Demand for proof
INFORMATION
Clinically relevant
Proven by research
Best up-to-date
evidence
“Isn’t this the way
we have always
practiced medicine?”
“Aren’t these just the
same old ingredients
tossed into a new
recipe?”
When am I supposed to find
the time to do that?
The basic steps of EBM
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness(validity
and relevance)
4. Apply the Evidence
Implement useful findings in clinical practice
Making a decision, by integrating the evidence
with your clinical expertise and the patient’s values.
5. Evaluate
The information, intervention, and EBM process
The Clinical Question
The FIRST step
The HARDEST step
The MOST IMPORTANT step!
FACT: We all have informational needs!
That is not a problem!
Problems arise
• if we fail to recognize those needs
• if we fail to bridge the information gap
• if we fail to ask the right questions
Asking good questions
is a skill to be learned.
Lee, exactly how
much time did you
spend on that big
project?
It will make life
easier for you...
And also for others
around you!
Hmmm… Is he
about to give me a
BONUS?
Or is he about
to FIRE me?
Lee, can you give me an
accounting of the extra time
you spent on that project so
that I can charge it back to
the client?
A GOOD QUESTION…
•
Is focused and relevant
•
Provides clear
communication
•
Clarifies your goal or need
•
Will reduce the amount of
time needed to obtain the
answer
Oh sure! I’ll have it
on your desk by
tomorrow!
Asking Questions
Foreground
Questions
Background
Questions
Novice
Expe
The Question
• Background
–
–
–
–
–
–
–
Anatomy and Physiology
Pathophysiology
Pharmacology and Toxicology
Differential diagnosis
Diagnostic testing
Treatment
Textbooks, reviews, lectures, experts
The Clinical Question
• Foreground
– Detailed information
– Patient focus
– Evidence-based process
WHEN PRACTICING EBM,
a good question must also:
•
Be specific
Identify the problem, clarifiy
the clinical issue
•
Be answerable
through the literature
•
Contain multiple aspects
(patient, options,
comparisons, etc)
It should NOT involve a
question of Personal Preference
or Local Concern.
EBM QUESTION: Should include multiple factors
(Examples)
P
PATIENT
type of patient or population
Ex: 47 yr male w/DM2 and cellulitis toe, 25 yr female w/DVT and chest pain
E
EXPOSURE
environmental, personal, biological
Ex: TB, tobacco, drug, diet, pregnancy or menopause, MRSA, allergy
I
INTERVENTION
clinical intervention
Ex: medication, procedure, test, surgery, radiation, drug, vaccine
C
COMPARISON compare alternative treatment
Ex: other prior, new or existing therapy
O
OUTCOME
clinical outcome of interest
Ex: Reduced death rate in 5 yrs, decreased infections, fewer hospitalizations
Scenario and Question
«
A healthy adult presents to the
clinic inquiring about the aspirin
that it might prevent heart attack ?
The Question
“In
an asymptomatic adult and no
risk factors, would the use of
aspirin reduce the incidence of
cardiovascular events?
Aspirin and Primary Prevention
1. Patient population.
2. Intervention.
Asymptomatic adults with no
risk factors
Aspirin
3. Comparison
intervention.
Placebo
4. Outcomes.
Incidence of CV events
“In asymptomatic adults no risk factors, would the
use of aspirin reduce the incidence of cardiovascular
events?
Scenario and Questions (Cont’d)
Scenario
A 32-year-old man, single, teacher in primary
school, known to have IBS for last 3 years
with no response to conventional medication.
I decided to search for effect of TCA in
patients with IBS.
Use of TCA in IBS
1. Patient population.
2. Intervention.
Middle age adults with IBS
Using of TCA
3. Comparison
intervention.
dietary fibers, bulking
agents and mebeverne
4. Outcomes.
Relieving of symptoms
“In middle age adults with IBS, would the use
of TCA reduce the pain and improve symptoms?
FRAMING THE QUESTION (Example: PICO)
ELEMENT
PROMPTS THE QUESTION:
Patient
Intervention
Comparison
Outcome
How would I describe a group of patients similar to mine?
What main action am I considering?
What is/are the other options?
What do I (or the patient) want to happen (or not happen)?
Example:
P:
In kids under age 12 with poorly controlled asthma on metered
dose inhaled steroids…
I: would the addition of salmetrol to the current therapy
C: compared to increasing the dose of current steroid
O: lead to better control of symptoms without increasing side effects?
CATEGORY OF QUESTION
MAJOR CATEGORIES
1.
2.
3.
4.
Diagnosis
Prognosis
Therapy/ Treatment
Harm (iatrogenic, other)
MISCELLANEOUS
• Quality of care
• Health economics
• Office Management
• Etc.
PICO
PEO
THE PATIENT’S QUESTIONS
Must be considered!
Often QUALITATIVE (not based on measureable outcomes)
Feelings, ideas, experiences, preferences, concerns, fears, beliefs,
ethnicity
Usually based on LIMITED BACKGROUND
Perception of problem
Self-diagnosis
Treatment wanted or needed
Alternatives (read, heard, considered, tried)
What is the patient hoping to avoid?
What benefits does the patient want or need most?
Etc.
QUANTITATIVE vs QUALITATIVE QUESTIONS
QUANTITATIVE: “Solid Evidence”
•
Measurable answer or response
•
Necessary for scientific study
•
Necessary for the practice of EBM
QUALITATIVE: “Quality of Life”
•
“Fuzzy” data - Impact on daily life, work, family, etc.
•
May be very important and influential to decisions –
especially for the patient
•
Creates added challenge or twist to practice of EBM
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
Some examples:
Questions from our clinics
•
•
•
•
•
•
•
•
What to do with IBS patients?
Management of premenopousal women.
How to deal with psychosomatic cases ?
Guidelines for shifting patient from one drug to
another ?
Proper management of IBS ?
Assessment of ED ?
Assessment of prostatic enlargement ?
Assessment of alcohol intake.
Find the Best Evidence
“The Literary Search”
HINT: If your desk looks like this, it’s probably the
LAST place you should start looking!
Find the Best Evidence
“The Literary Search”
The BEST EVIDENCE is:
External - from outside resources (researchers, experts)
Current – not out of date, most recent
High Quality - accurate, precise, effective, safe
Patient focused - applicable and appropriate for your individual
patient
FIVE STEPS TO FINDING THE BEST EVIDENCE
1.
IDENTIFY NEEDS:
What type of information is needed?
2.
IDENTIFY RESOURCES:
Types, Availability, Timeliness,Costs?
3.
SEARCH & RETRIEVE:
Use efficient strategies
4.
REVIEW :
Check quality and usefulness of info
5.
INTERPRET:
Help patient understand info, application
WHAT TYPE OF INFORMATION IS NEEDED?
WHAT CATEGORY IS THE QUESTION?
•
•
•
•
Diagnosis
Prognosis
Therapy
Harm
WHAT STUDY DESIGN FITS IT BEST?
There are MANY study designs!
EXPERIMENTAL TRIALS
(Answers questions of diagnosis or treatment)
Randomized Controlled Trials (RCTs)
Controlled studies
Blinded vs Open
ETC.
OBSERVATIONAL STUDIES
Descriptive reports
Retrospective studies
Cohort studies
Case Control
ETC.
EXAMPLE
Randomized Controlled Trials (RCT)
“Gold Standard” of research
Ideal experimental design - Best design for TREATMENT questions
Must identify objective of treatment
(Ex: cure, prevent complication, palliation, reassurance)
Still not always the right intervention for individual patient at that particular time and
place
What type of evidence best addresses the question, problem or issue?
CLINICAL PRACTICE
APPROPRIATE DESIGN FOR CLINICAL RESEARCH
Diagnosis, Dx testing
Cross-sectional study – not randomized trial
Prognosis
Follow-up studies of patients evaluated at same early point of illness
Therapy, treatment
RCT or Systematic review of multiple RCTs must be used
Avoid non-experimental approaches to avoid false conclusions about efficacy
Exceptions:
When treatment may be successful in an otherwise fatal condition
When no studies are available (rare conditions, new treatments, etc.)
Harm
RCT, Cohort, Case-control
OTHER INFORMATIONAL
Explore hypothesis
History-taking
Individual trial & error
Following clinical course
Recordkeeping
Quality of Care research
Qualitative research
Case control study
n of 1 trial
Cohort study
Systematic registry-based (computer supported) research
Individual peer review, Process Evaluation
MISCELLANEOUS
Basic Science, Genetics, Immunology, etc.
WHAT FORM OF INFORMATION?
Case report
Controlled Trial
Systematic review
Meta-analysis
Clinical guidelines
etc.
LITERARY SEARCH: NEXT STEP
IDENTIFY YOUR RESOURCES
Colleagues
Consultation, Discussion
(Caution: Response may be an outdated “This is what we do”)
Paper resources
books, reports, journals
Electronic databases
Health Literature Services
specialized librarians, staff
Review services, Abstract Services, etc.
SEARCH AND RETREIVE THE BEST EVIDENCE
Learn and Practice various SEARCH STRATEGIES:
• To find useful information quickly
• To eliminate irrelevant, inappropriate or weak information
Try to develop the habit of learning as you go;
Not just in lengthy formal sessions!
LITERARY SEARCH STRATEGY
ASK FOR HELP!
SPECIALIZED PERSONNEL
• track down information, textbooks, articles,
guidelines
• may provide electronic search support or training
EXAMPLES
• Medical Librarians
• Medical Informatics Specialists
• Specially trained staff member
LITERARY RESOURCES
•
TEXTBOOKS (caution – most obsolete!)
• Traditional
• Evidence Based
•
JOURNALS (may be outdated)
•
REVIEW ARTICLES (summaries, abstracts)
•
SYSTEMATIC REVIEWS (prepared in systematic, rigorous
manner) Ex: Cochrane Collection
•
META-ANALYSIS
•
CLINICAL PRACTICE GUIDELINES
Summarized and easily digestible information
ELECTRONIC RESOURCES, DATABASES, INTERNET
Bibliographic Database
Example: Medline, PubMed
Medical Information Services: Medscape, HDCN
Review Services
Subjective
Systematic Reviews
Meta-analysis
Examples:
• Cochrane,
• Best Evidence,
• Up to Date
MORE GREAT INTERNET RESOURCES
Websites
cyberNephrology, National Kidney Foundation. NIDDK,
American Heart Association, American Cancer Society.
National Institutes of Health, etc
Listserve Discussion Groups
CyberNephrology, C-span, etc.
Specialty Electronic Databases
Psyclit
CancerLit
CINAHL
(allied health and nursing journals)
Etc
OTHER RESOURCES
Tapes
Videos
CD-ROMs
Specialty seminars
Product information and comparisons
A closer look at some Internet Resources…
MEDLINE
WHAT IS IT?
Searchable database of medical information compiled by National Library of
Medicine in US 1966-present
Catalogs articles from approx 4000 world journals (of estimated 12-15k total)
SEARCH METHODS
Any word or words (title, abstract, content, author name, institution, etc.)
Medical Subject Heading (MeSH) terms
A restricted thesaurus of medical titles
Articles categorized by most specific possible MeSH heading
COST: FREE!
Or may subscribe to companies with specialized search strategies:
•
Ovid Technologies (ovid)
•
Silver Platter Information (WinSPIRS)
BENEFITS
Free
Vast database
LIMITATIONS
Not all articles are indexed on Medline (only 1/3 of approx 10 million!)
Much material listed and described on Medline can only be accessed through
journal article
MEDLINE: ELECTRONIC SEARCH STRATEGIES
Search through “Clinical Queries” service of PubMed
http://www.ncbi.nlm.nih.gov/clinical.html
Medical Subject Headings (MeSH)
Search filters
Search by a text word can supplement a MeSH search
Boolean search: “and”, “not”, etc.
To increase sensitivity
• use “explode” command
• avoid using subheadings
Online Tutorial is available!
COCHRANE LIBRARY
Cochrane Database of Systematic Reviews
-systematically compiled reviews of intervention
Cochrane Controlled Trials Register
-citations of controlled trials identified anywhere in the world
Cochrane Review Methodology Database
-methodological papers relating to systematic reviews
Etc.
BEST EVIDENCE
Electronic version of two publications:
•
Evidence Based Medicine
•
American College of Physicians Journal Club
Covers broad topics of information
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
CRITICAL APPRAISAL
Interpreting the evidence
• How to read a paper
• How to do the math
CRITICAL APPRAISAL
IMPORTANT!
You do NOT have to become a researcher,
epidemiologist, or statistician to practice EBM.
Focus on how to USE research reports –
not on how to generate them!
CRITICAL APPRAISAL
HOWEVER…
You must have a solid understanding of
basic research principles and
study designs in order to understand
and interpret the evidence!
TYPES OF STUDIES AND REPORTS
Randomized Controlled Trial - “The Gold Standard”
Systematic review
Meta-analysis
Retroactive vs Prospective
Incidence
Prevalence
Case Control
Cohort (Follow-up)
Cross-sectional
Ecologic
Longitudinal
Experimental
Blinded vs Open
Qualitative Screening
DETOUR
BASIC RESEARCH PRINCIPLES
STUDY DESIGNS
THE TIME FACTOR
When was the study done?
What was its duration?
In what time direction is it headed?
RETROSPECTIVE
PROSPECTIVE
THE TIME FACTOR
When was the study done?
What year?
What technology? (ie: test, drug, equipment, procedure)
Any associated social factor or historical event?
THE TIME FACTOR
What was the Study Duration?
Was it an appropriate length of time for the
intended goal?
Limited time study or ongoing?
Was study completed? Stopped early?
In what direction is it headed?
RETROSPECTIVE
“LOOKING BACK”
Historical Review or
Investigation
PAST
PROSPECTIVE
“LOOKING FORWARD”
Future Results
The Great Unknown
PRESENT
FUTURE
In what direction is it headed?
RETROSPECTIVE
PROSPECTIVE
PRO
•Lower risk of bias
PRO
•May provide good
direction for future study
CON:
May get faulty results based
on incomplete data or
insignificant subgroups
“Hind Sight is 20/20”
CON:
•Prone to Bias
•A“Fishing Expedition” for
positive results
PRESENT
(Example of Error: Untreated
hypertension unlikely to cause
cardiac event in child, so treatment
is unnecessary below age 18yrs)
“Was there a similar comparison group?”
No comparison group
All subjects receive Experimental Intervention
Experimental
Intervention
UNCONTROLLED STUDIES
NO EVENT
Experimental
Intervention
OUTCOME
EVENT
“Trial and Error?” or “Before & After?”
UNCONTROLLED STUDIES
Generally NOT accepted:
Potentially Dangerous and Flawed
Prone to BIAS!
“Traditional Study Method”
May produce strong results
“Trial and Error”
“Before & After”
PROBLEMS
BENEFITS
POSITIVE OUTCOME MAY BE DUE
TO:
•Other factors
•Natural course of disease (some
get better, some don’t!)
Can answer some questions
about:
•likelihood of response
•adverse effect, etc.
•Spontaneous change of health
•Placebo Effect
VERY PATIENT-SPECIFIC!
•Hawthorne Effect
NEGATIVE OUTCOME
May be due to study treatment.
Could be disastrous!
MAY BE ONLY OPTION
Rare conditions
Previously unknown conditions
UNCONTROLLED TRIALS:
“TRIAL AND ERROR”
Example#1
SMALLPOX
VACCINATION
James Phipps,
age 8 years
GOOD!
Resistant to
Cowpox and
Smallpox
(NO DISEASE
OUTCOME)
SMALLPOX VACCINE
1. 1796: Edward Jenner inoculates 8yr-old James Phipps with cowpox virus
from a milkmaid’s hands.
Child develops illness, recovers.
2. Two weeks later, inoculates same child with smallpox virus.
Child survives, no illness.
(Centuries later, smallpox eradicated!)
n=1
UNCONTROLLED TRIALS:
“TRIAL AND ERROR”
Example #2
Drinks culture of
H.pylori
Dr. Marshall
Microbiologist
n=1
NO
OUTCOME
SEVERE
GASTRITIS
HELICOBACTER PYLORI - GASTRIC ULCERS
1982: Australian microbiologist Barry J. Marshall presents evidence showing a
possible infectious cause for gastric ulcers. Suggests they may be treatable with
antibiotics.
Findings are met with disinterest and disbelief by medical community. Lacks
support for further study.
5 years later: Prepares a broth of live organisms isolated from a gastric ulcer
patient and drinks it. Becomes violently ill, develops severe acute gastritis.
1990’s Antibiotics are used routinely to cure some gastric ulcers!
UNCONTROLLED TRIAL
RECOVERED
Experimental
Intervention
May represent the ONLY
treatment option for a new or rare
disease
Present
DIED
FUTURE
STRONGLY PREFERRED! Reduces BIAS. Provides stronger results.
Experimental
Intervention
Control
Group
CONTROLLED STUDY
Only the TEST group receives the Experimental Intervention
ExperimentalI
ntervention
Control group may receive…
Nothing
Placebo
Observation only
Other
IMPORTANT
All other differences
should be minimized or
eliminated to reduce
potential BIAS
Gold Standard
Treatment
RANDOMIZED CONTROLLED TRIAL (RCT)
“The Gold
Standard”
Experimental
Intervention
Control
Group
THE FIRST RANDOMIZED CONTROLLED TRIAL
By Sir Austin Bradford Hill
Streptomycin
(n=50)
(BLINDED)
Bedrest
(n=50)
1944 TUBERCULOSIS TREATMENT: Streptomycin vs Bedrest
OPEN vs BLINDED STUDIES
Experimental
Intervention
OPEN
Control
Group
OPEN vs BLINDED STUDIES
BLINDED
TRIAL
BLINDED
BLINDED
TRIAL
BLINDING
SINGLE BLINDED:
Pt unaware of what group s/he is in
DOUBLE BLINDED:
Pt and MD unaware
OPEN LABEL:
Everyone is aware
RANDOMIZED vs NON-RANDOMIZED TRIALS
Experimental
Intervention
How is this
group divided?
Control
Group
NON-RANDOMIZED
Experimental
Intervention
Assigned to
groups, usually
by the
researcher
Control
Group
Potential for RESEARCHER BIAS!
RANDOMIZED
Experimental
Intervention
Random method of
assignment used
Control
Group
Maximizes “sameness,” Eliminates BIAS!
RANDOMIZED CONTROLLED TRIAL (RCT)
(EXPERIMENTAL TRIAL)
Experimental
Intervention
“The Gold Standard”
Control
Group
Present
FUTURE
CROSSOVER TRIALS
ONE GROUP, MULTIPLE TESTS
(Best if participants are blinded)
Intervention
A
Intervention
Intervention
A
Intervention
B
B
ASSESS
OUTCOMES #1
ASSESS
OUTCOMES #2
COMPARE OUTCOMES
CROSSOVER TRIALS
PROS & CONS
Fewer participants needed than a RCT!
Intervention
A
Intervention
Intervention
A
Intervention
B
B
ASSESS
OUTCOMES #1
ASSESS
OUTCOMES #2
All are in experimental group
Lower costs
CROSSOVER TRIALS
PROS & CONS
MUST HAVE SHORT CARRYOVER EFFECT
MUST HAVE SHORT WASHOUT EFFECT
Intervention
A
Intervention
Intervention
A
Intervention
B
B
ASSESS
OUTCOMES #1
ASSESS
OUTCOMES #2
(OR WAIT A SUITABLY LONG WASHOUT TIME!)
CASE CONTROL
(“A LOOK BACK”)
RISK FACTOR?
(PAST)
Present
CASE CONTROL
(“A LOOK BACK”)
HEALTHY
NEVER
SMOKED
RISK FACTOR
LUNG CANCER
SMOKER
(PAST)
Present
CASE CONTROL
(“A LOOK BACK”)
NON-DIABETIC
NORMAL
WEIGHT
RISK FACTOR
DM TYPE II
OBESITY
Present
COHORT“FOLLOWUP DESIGN”
IS RISK
FACTOR
PRESENT?
(Exclude those
with outcome
already!)
Future Outcome
COHORT
TO INVESTIGATE ETIOLOGY
OR HYPOTHETICAL CAUSE
OF DISEASE/OUTCOME
IS RISK
FACTOR
PRESENT?
“FOLLOWUP DESIGN”
Present
Future Outcome
COHORT
EXAMPLE
RISK FACTOR
Hgb <9
DIALYSIS PATIENTS
Present
Measures future outcome for
dialysis pts w/o treatment of anemia
CROSS SECTIONAL DESIGN
? Cause ? Risk factors
A look back
CROSS SECTIONAL DESIGN
OTHER CAUSES
RISK = SLEEP PRONE
SIDS DEATHS
INFANT
DEATHS
Problems of looking back
NON-SIMILAR
CONDITIONS
Social
Personal
Comorbid conditions
Other treatments
Etc.
Not usually
accepted by
medical journals
(accepted in
popular press,
not reviewed)
VARIATION IN
TREATMENT
OR METHOD
NO
CONTROL
OVER
CONTROL
GROUP
CURRENT
GROUP OF
PATIENTS
RANDOMIZED & CONTROLLED TRIAL (RCT)
Experimental
Intervention
MAY BE
BLINDED
Control
Group
PROSPECTIVE
START WITH YOUR TARGET POPULATION
START WITH YOUR TARGET POPULATION
Set CRITERIA for
INCLUSION / EXCLUSION
This will determine:
ELIGIBILITY at the start
VALIDITY at the end
START WITH YOUR TARGET POPULATION
ELIMINATE THOSE WHO DO NOT MEET THE CRITERIA
NEXT: GATHER A SAMPLE GROUP
THE SAMPLE GROUP WILL:
•Represent the target population
•Meet the criteria for inclusion / exclusion
SIDE NOTES…
Study should be approved by an
Ethics Committee
Informed consent should be
obtained from study participants
SAMPLE GROUP MAY BE SUBDIVIDED FURTHER
STRATIFICATION
Divide into subgroups based on
important similar characteristics
RANDOMIZATION
Divide into sub-groups based on
unknown confounders
STRATIFICATION
“important similar characteristics”
Examples:
• Male or Female
• Age
• Stage of illness
• Prior illness or treatment
• Hospital vs Office groups
• Comorbid condition
• Etc.
EXAMPLE OF
STRATIFICATION
FEMALE
MALE
RANDOMIZATION
“unknown confounders”
Examples:
• Postal code
• Month of birth
• Random number
• Etc.
EXAMPLE OF
RANDOMIZATION
DX IN JANUARY-JUNE
DX IN JULY-DECEMBER
Next… Divide your sample group(s) into STUDY GROUPS
Experimental
Intervention
Control
Group
“Test Group”
“Baseline Group”
Next… Divide your sample group(s) into STUDY GROUPS
“Test Group”
Experimental
Intervention
Receives Experimental
Intervention
“Baseline Group”
Control
Group
•
•
•
•
•
Nothing
Observation
“Same” miscellaneous
intervention (nonexperimental)
Placebo
“Gold Standard” therapy especially if unethical to do
otherwise!
ASSIGN PATIENTS TO STUDY GROUPS
Experimental
Intervention
Use caution against bias!
Control
Group
Sample Group
Study Groups
STUDY INVESTIGATOR
 usually assigns
patients to study
groups.
Experimental
Intervention
 usually has a
personal preference
for the treatment or
patient
 might unconsciously
Control
Group
“work harder” to
make the study work
with non-preferred
candidates
= POTENTIAL FOR
BIAS
RANDOMIZED CONTROLLED TRIAL (RCT)
Experimental
Intervention
Use random
separation
and assignment!
Control
Group
RANDOMIZED CONTROLLED TRIAL (RCT)
Experimental
Intervention
Control
Group
RANDOMIZED CONTROLLED TRIAL (RCT)
Experimental
Intervention
Control
Group
Present
Proceed with study
FUTURE
RANDOMIZED CONTROLLED TRIAL (RCT)
Experimental
Intervention
EXPERIMENTAL EVENT
RATE (EER)
Control
Group
CONTROL
EVENT RATE
(CER)
RANDOMIZED CONTROLLED TRIAL (RCT)
“The Gold
Standard”
Experimental
Intervention
EXPERIMENTAL EVENT
RATE (EER)
Control
Group
Present
CONTROL
EVENT RATE
(CER)
FUTURE
Disadvantages of RCT
Expensive
large # pts needed
Prolonged recruitment and follow-up time needed
Funding difficult to obtain except w/support of
pharmaceutical companies (problematic!)
RETURN FROM DETOUR
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
HEIERARCHY OF EVIDENCE
(value of study design to maximize wt, minimize bias)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Systematic Review of all relevant RCTs
At least one properly designed RCT
Trials and case studies
Well-designed Controlled Trial without Randomization
Well designed Cohort or Case Control Studies, preferably from >1
centre or group
Multiple Time series with or without intervention
(Exception: Dramatic results in uncontrolled trials, such as
introduction of PCN in the 1940s)
Opinions of respected authorities, based on
Clinical expertise
Descriptive studies
Reports of Expert Committees
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
THE FIVE BASIC STEPS OF EBM
1. Clinical Question
Patient-focused, problem-oriented
2. Find Best Evidence
Literary Search
3. Critical Appraisal
Evaluate evidence for quality and usefulness
4. Apply the Evidence
Implement useful findings in clinical practice
5. Evaluate
The information, intervention, and EBM process
Evaluate
INFORMATION
Adequate resources?
Ease or Difficulty of finding and getting desired information?
Costs?
INTERVENTION
Patient response or acceptance?
Ease or Difficulty of Application?
Clinical outcomes?
EBM PROCESS
EFFECT ON PRACTICE
Will this particular experience change our thinking or practice?
SELF EVALUATION
How did we do? (Question, Search, Appraise, Apply)
How could we improve our own EBM performance?
EBM: PROS, CONS and LIMITATIONS
PROS
Clinicians update knowledge base routinely
Improved understanding of research methods
Physician becomes more critical in use of data
Increased confidence in management decisions
Increased computer literacy, data search technology
Better reading habits
Provides framework for group problem solving, team generated
practice
Transforms weakness or paucity of knowledge into positive change
OK to be uncertain
OK to be skeptical
OK to be flexible
Integrates medical education, research and clinical expertise
Can be learned by non-clinicians – other HCWs, patient groups,
purchasers, etc.
Allows us to keep up with our better-educated patients!
Increased contribution of junior MDs
Increased patient benefit
Better communication with patients re: rationale of management
decisions
Promotes better and more appropriate use of limited resources
May reduce costs or medical care or practice by eliminating outdated or
unnecessary factors
Can be learned at any stage of physician’s career
CONS
Time consuming
Information overload
Time to learn and practice
Time may be needed for team conferencing, planning and review
Takes $$$ to establish resource infrastructure – library, office, etc.
computers, peripherals
Internet costs
Programs, software information, CD-ROMS
Subscription costs – online and paper resources
May increase cost of care (but hopefully offset by elimination of
unnecessary medical interventions, tests, journals, etc. – plus save time
in getting proper intervention)
Online references made to unavailable journals or references
Exposes gaps in the evidence (but provides ideas for researchers!)
Requires computer skills (but can be done with minimal
computer literacy and skill)
May expose your current practice as obsolete or dangerous
(loss of authority and respect)
LIMITATIONS
Lack of evidence (shortage of studies)
Difficulty applying evidence to care of a particular patient
Barriers to the practice of high quality medicine
Lack of skills (search, appraise, etc.)
(foster development of new
skills!)
Lack of time to learn and practice EBM (promotes lifelong learning thru
better focus)
Lack of physician resources for instant access to evidence (EBM has
worldwide applicability)
RESTRICTED AVAILABILITY OF LAB TESTS
NON-TEXTBOOK CASE
co morbidity, additional risk factors
AFFORDABILITY (MD & PT)“I can’t afford to practice EBM.”
Language barriers – available evidence may be unreadable, should be
included
Physician attitude: Can be the greatest limitation!
“It decreases the importance of my clinical expertise”
(that’s a necessary component!)
“It only applies to those involved in research.”
(promotes cooperation among multiple physicians)
“It ignores patient values and preferences.”
“It’s just another cookbook approach to medicine.”
“It’s a poorly disguised way to cut medical costs.”
(cost of care may actually increase)
“It’s a way to ration care and resources.”
(Provides better utilization of avail resources)
DISAGREEMENT
Pt’s comfort, choice, acceptance, values preferences
Vs MD’s recommendations
DOES RISK OR SIDE EFFECTS OF TREATMENT OUTWEIGHT THE
BENEFITS?
The unanswered question…
“DOES EBM REALLY MAKE A DIFFERENCE?”
Effect of practicing EBM on patient outcome is actually
unknown – no studies done
EBM good based on population studies:
(ie: Pts who rec’d ___ generally fare better than those who don’t)
EBM IN DEVELOPING COUNTRIES
LIMITED RESOURCES
May help to eliminate unnecessary or poor quality
screening tests (ie: resting EKG to screen for
CAD = high false negative and false positive
rates)
LIMITED DRUG REGULATION
Approval for drug marketing easy - promotes
insurgence of new drugs for questionable
indications, limited effectiveness, false claims,
inflated prices based on ad response (include
“more expensive is better”)
EBM IN DEVELOPING COUNTRIES
LIMITED CAPACITY FOR CME
Drug companies - may sponsor meetings that are little
more than captive marketing sessions or biased
education sessions (drug education vs promo)
Result may be push for more expensive, less effective
treatments (ie push for CCB’s over BB’s) - calc channel
blockers over Beta Blockers
EBM IN DEVELOPING COUNTRIES
LIMITED ACCESS TO LITERATURE DATABASES
Desktop computer with CD ROM reader and modem
($900)
Electricity
1 yr subscription to MedLine on CD ROM (?500)
Internet connection $25/mt
Convince administrators of expense:
Publicly cite how searches help with lectures, research
and patient care management decisions
Get equipment from drug companies
(usually strings attached)
EBM IN DEVELOPING COUNTRIES
LIMITED ACCESS TO ADEQUATE LIBRARY FACIILITIES
ALMOST INEVITABLE IN DEVELOPING COUNTRIES
Identify resources via search, but then unable to retrieve articles!
A top EBM practitioner (Philippines) recommends:
1. Top 3 medical libraries in your country
2. Multinational drug company libraries
3. Friends and colleagues - including in other countries
EBM IN DEVELOPING COUNTRIES
QUESTIONABLE APPLICABILITY OF ARTICLES
RETRIEVED
Article describes a treatment that worked in one country, but
seems impossible in yours
Check…
•
•
•
•
•
Are there pathophysiologic differences?
Will patient differences diminish the treatment response?
Patient compliance issues?
Provider compliance issues?
Co-morbid conditions which will alter the benefits or risks?
EBM IN DEVELOPING COUNTRIES
OBSTACLES TO TEACHING OR LEARNING EBM
Your Hospital or Institution does not reimburse for time spent on
Continuing Medical Education programs
The standard 5-day workshop would be far too costly to provide or
attend!
Need to learn the basics - computer skills, etc.
TRY THESE!
Combine efforts to learn more and practice EBM with handful of
colleagues (small group learning)
Ask about basis for information provided by drug reps, medical supply
companies, etc. It will prompt them to provide you with on the spot
teaching and better information, too!
EBM LIBRARY
BASIC REQUIREMENTS
Convenient – easy access at point of contact with patient if
possible
Current – Up to date information
Electronic Database – Should be included
• Online
• CD-ROM
ELECTRONIC DATABASES
Evidence-Based Medicine Reviews (EBMR) – from Ovid
(ovid.com)
- combines Cochrane, Best evidence, Evidence Based
Mental health, EB Nursing, Cancerlit, healthstar, AIDSline,
Medline, and journal links (Described by one EBM specialist
as “the best”)
Cochrane Library – “Gold Standard” for systematic reviews
Best Evidence
Medline – world’s largest, free resource – over 10 million
references
PERSONNEL
Medical Librarian
Informatics Specialist
“We can learn a great deal about current best information
sources from librarians and other experts in medical
informatics, and should seek hands-on training from them
as an essential part of our clinical training.”
(ch 2 p29-30 – Blue circled 2)
PRINTED RESOURCES
TEXTBOOKS
most obsolete!
Some updated yearly, plus heavy references and scientific
evidence for support
Clinical Evidence (BMJ Publishing Group & ACP – 1999present)
Evidence-Based On Call (http//cebm.jr.ox.uk/eboc/eboc.html)
Up To Date (General medicine, CD format, Medline abstracts
used for evidence)
Scientific American Medicine – limited references from
Medline, Harrisons
JOURNALS
Traditional Journals
subject to author submissions
specialists need to read and evaluate
may subscribe to services that send articles of interest to
your specialty
timely, instant information at time of publication
Ex: NEJM, Clinical Nephrology, etc.
Evidence Based journals
selects best studies from multiple journals of interest,
summarizes best evidence
Good for use by generalists
Lag time from original publication: 3-6 months
Ex: Evidence Based Medicine, Evidence Based
Nursing, Evidence Based CV Medicine, etc.
SPECIAL RESOURCES
WHO Blue trunk
Hinari
PATIENT RESOURCES
Medical treatments www.nlm.nih.gov/medlineplus
Medical guidelines www.guideline.gov
EVIDENCE BASED MEDICINE