2. Outline of TalkOutline of Talk
Definition of EBMDefinition of EBM
History of EBMHistory of EBM
Obstacles of EBMObstacles of EBM
How to practice EBM (How to practice EBM ( The Five A’s )The Five A’s )
3. What is EBM?What is EBM?
Evidence-based medicine (EBM) is the integration of bestEvidence-based medicine (EBM) is the integration of best
research evidence with clinical expertise and patient values.research evidence with clinical expertise and patient values.
Elements of EBM:Elements of EBM:
1- Best research evidence: clinically relevant research that has been1- Best research evidence: clinically relevant research that has been
conducted using sound methodologyconducted using sound methodology
2- Clinical expertise: the clinician's cumulated experience, education2- Clinical expertise: the clinician's cumulated experience, education
and clinical skills.and clinical skills.
3- Patient values: the unique preferences, concerns, and3- Patient values: the unique preferences, concerns, and
expectations each patient brings into a clinical encounter.expectations each patient brings into a clinical encounter.
4. How did it start?How did it start?
Late 1970’s clinical epidemiologists at McMasterLate 1970’s clinical epidemiologists at McMaster
University wrote a series of articles on how to readUniversity wrote a series of articles on how to read
clinical journals calledclinical journals called critical appraisalcritical appraisal that werethat were
published in 1981 in Canadian Medical Associationpublished in 1981 in Canadian Medical Association
Journal.Journal.
This team started teaching the practice at the UniversityThis team started teaching the practice at the University
and the term changed to EBM in a document forand the term changed to EBM in a document for
resident applicants in 1990.resident applicants in 1990.
In 1991 the term EBM appeared in ACP JC.In 1991 the term EBM appeared in ACP JC.
5. Why EBM?Why EBM?
Daily need for valid information.Daily need for valid information.
Inadequacy of traditional textbooks – out of date,Inadequacy of traditional textbooks – out of date,
ineffective, overwhelming.ineffective, overwhelming.
Disparity between our diagnostic skills and clinicalDisparity between our diagnostic skills and clinical
judgment – and up to date knowledge and clinicaljudgment – and up to date knowledge and clinical
performance.performance.
The EBM process aims to make it easier to apply currentThe EBM process aims to make it easier to apply current
quality evidence from research in clinical and healthcarequality evidence from research in clinical and healthcare
decisions.decisions.
6. Obstacles to EBMObstacles to EBM
Shortage of coherent consistent scientific evidence.Shortage of coherent consistent scientific evidence.
Difficulty applying to my patient population.Difficulty applying to my patient population.
Developing skills for searching and appraising.Developing skills for searching and appraising.
TimeTime
Limited number of studies that show “EBM” works.Limited number of studies that show “EBM” works.
7. EBM - How to practice:EBM - How to practice:
The 5 A’sThe 5 A’s
AAsk – formulated clinical questionsk – formulated clinical question
AAcquire – best evidence to answer a questioncquire – best evidence to answer a question
AAppraise – evidence for validity, impact and applicabilityppraise – evidence for validity, impact and applicability
AApply – to our patientpply – to our patient
AAssess – effectivenessssess – effectiveness
8. AAsksk
Formulate the clinical question :Formulate the clinical question :
PICOPICO
PPatient’s problem and problem of interest;atient’s problem and problem of interest;
IIntervention, prognostic factor or exposure of interestntervention, prognostic factor or exposure of interest
CComparison interventionomparison intervention
OOutcomes of interestutcomes of interest
The question needs to be focused and searchable.The question needs to be focused and searchable.
9. Patient population and problem ofPatient population and problem of
interestinterest
How would you describe a group of patients similar to yours?How would you describe a group of patients similar to yours?
What are the most important characteristics of the patient?What are the most important characteristics of the patient?
Patient populationPatient population :: e.g. sex, age or race of the patiente.g. sex, age or race of the patient
Problem of interest : the primary problem, disease, or co-Problem of interest : the primary problem, disease, or co-
existing conditions.existing conditions.
10. Intervention, prognostic factor, orIntervention, prognostic factor, or
exposureexposure
Which main intervention, prognostic factor, or exposureWhich main intervention, prognostic factor, or exposure
are you considering?are you considering?
What do you want to do for the patient? Prescribe aWhat do you want to do for the patient? Prescribe a
drug? Order a test? Order surgery?drug? Order a test? Order surgery?
What factor may influence the prognosis of the patient?What factor may influence the prognosis of the patient?
Age? Co-existing problems?Age? Co-existing problems?
What was the patient exposed to? Asbestos? CigaretteWhat was the patient exposed to? Asbestos? Cigarette
smoke?smoke?
11. ComparisonComparison
What is the main alternative to compare with theWhat is the main alternative to compare with the
intervention?intervention?
Are you trying to decide between two drugs, a drug andAre you trying to decide between two drugs, a drug and
no medication or placebo, or two diagnostic tests?no medication or placebo, or two diagnostic tests?
Your clinical question does not always need a specificYour clinical question does not always need a specific
comparison.comparison.
12. OutcomesOutcomes
What can you hope to accomplish, measure,What can you hope to accomplish, measure,
improve or affect?improve or affect?
What are you trying to do for the patient?What are you trying to do for the patient?
Relieve or eliminate the symptoms?Relieve or eliminate the symptoms?
Reduce the number of adverse events?Reduce the number of adverse events?
Improve function or test scores?Improve function or test scores?
13. CaseCase
Zahra is 67 years old and has a history of congestive heart failureZahra is 67 years old and has a history of congestive heart failure
brought on by several myocardial infarctionsbrought on by several myocardial infarctions..
She has been hospitalized twice within the last 6 months forShe has been hospitalized twice within the last 6 months for
worsening of heart failure. At the present time she remains inworsening of heart failure. At the present time she remains in
normal sinus rhythm. She is extremely diligent about taking hernormal sinus rhythm. She is extremely diligent about taking her
medications (enalapril, aspirin and simvastatin) and wantsmedications (enalapril, aspirin and simvastatin) and wants
desperately to stay out of the hospital.desperately to stay out of the hospital.
You think she should also be taking digoxin but you are notYou think she should also be taking digoxin but you are not
certain if this will help keep her out of the hospital. You decidecertain if this will help keep her out of the hospital. You decide
to research this question before her next visit.to research this question before her next visit.
Formulate answerable focused clinical question?Formulate answerable focused clinical question?
14. PICO QUESTIONPICO QUESTION
PPatients: congestive heart failure, elderlyatients: congestive heart failure, elderly
IIntervention: digoxinntervention: digoxin
CComparison:omparison: none, placebonone, placebo
OOutcomes: primary (reduce need for hospitalization)utcomes: primary (reduce need for hospitalization)
secondary (reduce mortality)secondary (reduce mortality)
In elderly patients with congestive heart failure, is digoxinIn elderly patients with congestive heart failure, is digoxin
effective in reducing the need for re-hospitalization?effective in reducing the need for re-hospitalization?
15. Type of questionType of question
DiagnosisDiagnosis
TherapyTherapy
PrognosisPrognosis
Harm/EtiologyHarm/Etiology
16. Type of studyType of study
DiagnosisDiagnosis
prospective, blind comparison toprospective, blind comparison to
a gold standarda gold standard
HarmHarm
RCT > cohort > case control >RCT > cohort > case control >
case seriescase series
PrognosisPrognosis
cohort study > case control >cohort study > case control >
case seriescase series
TreatmentTreatment
RCT>cohort > case control >RCT>cohort > case control >
case seriescase series
18. AAppraiseppraise
Appraise the EvidenceAppraise the Evidence
Once an article is located, it is necessary to appraise its validity andOnce an article is located, it is necessary to appraise its validity and
importance before applying the results.importance before applying the results.
The specific analysis of the paper, regarding validity and importance etc,The specific analysis of the paper, regarding validity and importance etc,
depend on the type of study design and the nature of the question.depend on the type of study design and the nature of the question.
User’s Guide to the Medical Literature, JAMA 2002User’s Guide to the Medical Literature, JAMA 2002
1. Are the results valid?
2. What are the results?
3. How will these results help me work with my patients?
19. AApplypply
Apply the Results to Your PatientApply the Results to Your Patient
Is the evidence applicable to your patient, andIs the evidence applicable to your patient, and feasiblefeasible in yourin your
setting?setting?
Would your patient fit inclusion and not exclusion criteria?Would your patient fit inclusion and not exclusion criteria?
Were all clinically important outcomes considered?Were all clinically important outcomes considered?
Are costs and risks acceptable?Are costs and risks acceptable?
Are patients values/expectations considered?Are patients values/expectations considered?
20. AAssessssess
Assess the OutcomeAssess the Outcome
The final step includes an evaluation of yourThe final step includes an evaluation of your
performance in searching the literature, as well as anperformance in searching the literature, as well as an
assessment of the patient’s response.assessment of the patient’s response.
Perform self evaluations to improve your skills inPerform self evaluations to improve your skills in
using EBM.using EBM.
21. Self EvaluationSelf Evaluation
Are my questions well formulated?Are my questions well formulated?
Am I effectively/efficiently searching?Am I effectively/efficiently searching?
How am I doing with critical appraisal?How am I doing with critical appraisal?
Am I integrating what I have learned into clinicalAm I integrating what I have learned into clinical
practice?practice?
Are patients benefiting?Are patients benefiting?
22. EBM conclusionEBM conclusion
The use of current best available evidence inThe use of current best available evidence in
making decisions about patient care whilemaking decisions about patient care while
considering patient values.considering patient values.
Requires skills for critical appraisal as well asRequires skills for critical appraisal as well as
skills for applying evidence appropriately toskills for applying evidence appropriately to
individual patients.individual patients.
Lifelong process of learning enhanced by self-Lifelong process of learning enhanced by self-
evaluation.evaluation.