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SS/EBM/Intro/2010
E vidence
Sudigdo Sastroasmoro([email protected])
Medical School University of Indonesia
(”Bringing research evidenceinto practice”)
(”Bringing research evidenceinto practice”)
B ased
M edicine
SS/EBM/Intro/2010
Dr. Benjamin Spock:Baby and Child Care
“I think it is preferable to accustom a baby to sleeping on his stomach from the start of he is willing. He may change later when he learns to turn over”.
Later evidence indicates that prone position is aan significant risk factor for SIDS (sudden infant death syndrome)
SS/EBM/Intro/2010
Fletcher & Fletcher: CE = The application of
epidemiologic principles in problems encountered in clinical medicineSackett et al: CE = The basic science for clinical medicineMuch resistance by expertsEBM: In principle – no one disagreeAll major medical journals have adopted EBMCenters for EBM all over the world
EBM & Clinical Epidemiology
SS/EBM/Intro/2010
Previous practice:
6 yrs medical
education
40-50 yrsmedical practice
Problems with patients:
Dx, Rx, Px
Consultants, colleaguesTextbooksHandbooks
Lecture notesClinical
guidelinesCME, seminars,
etcJournals
Usu. see only Results section,
or even worse, Abstract section
SS/EBM/Intro/2010
Trust meIn my experience ….LogicallyTextbook, handbook, capita selecta
SS/EBM/Intro/2010
What is Evidence-based Medicine?
“The conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients”
“Pemanfaatan bukti mutakhir yang sahih dalam tata laksana pasien”
Integration of (1) physician’s competence (2) valid evidence from studies (3) patient’s preference
SS/EBM/Intro/2010
Pros : “New paradigm in medicine” “Extraordinary innovations,
only 2nd to Human Genome Project” Cons : New version of an old song ‘Fair’ : Nothing wrong with EBM, but:
Be careful in searching evidence Meta-analyses, clinical trials, etc. should be critically appraised
Keyword for EBM: Methodological skill to judge the validity
of study reports (Re. Andersen B: Methodological errors in medical research, 1989)
SS/EBM/Intro/2010
(Mark Twain)
“Hierarchy of Lies”
SS/EBM/Intro/2010
WHY EBM?1. Information overload 2. Keeping current with literature3. Our clinical performance
deteriorates with time (“the slippery slope”)
4. Traditional CME does not improve clinical
performance5. EBM encourages self directed
learning process which should overcome the above shortages
SS/EBM/Intro/2010
>25,000 periodical (journals)6,000,000 articles annually17,000 biomedical books annually3000 recognized diseases1500 therapeutic regimens (+250 annually)
The fact……..
SS/EBM/Intro/2010
The Flora and Fauna of the Medical Jungle
Original ResearchAcademic ReviewsDecision/Cost AnalysisMedical Cookbooks (Practice Guidelines)Translation JournalsCMEClinical Experience
ExpertsNewsletters and Survey ServicesPharmaceutical RepresentativesComputer sourcesAudiotapesQualitative Research
SS/EBM/Intro/2010
Our textbooks are out-of-date
Fail to recommend Rx up to ten years after it’s been shown to be efficacious.Continue to recommend therapy up to ten years after it’s been shown to be useless.
SS/EBM/Intro/2010
The inevitable consequence:
On average, the clinically-important knowledge of physicians deteriorates rapidly after we complete our training.
SS/EBM/Intro/2010
Years after graduation
Relative% ofremainingknowledge
2 4 6 8 10 12
$100%
THE SLIPPERY SLOPE
SS/EBM/Intro/2010
1. Formulate clinical problems in answerable questions
2. Search the best evidence: use internet or other on-line database for current evidence
3. Critically appraise the evidence for Validity (was the study valid?) Importance (were the results
clinically important?) Applicability (could we apply to our
patient?)4. Apply the evidence to patient5. Evaluate our performance
Steps in EBM practice
VIA
SS/EBM/Intro/2010
Diagnosis(Determination of disease or problem)
Treatment(Intervention necessary to help the patient)
Prognosis(Prediction of the outcome of the disease)
Main area
SS/EBM/Intro/2010
Meta-analysisClinical guidelinesEconomic analysis
Clinical decision makingCost-effectiveness analysis
Qualitative research
Others:
SS/EBM/Intro/2010
(I)Formulating clinical
questions
SS/EBM/Intro/2010
A 2-month old infant with large VSDBirth weight 3.1 kgWeight 3.8 kg, HR=132, RR 68Retractions (+)Systolic murmur, gallop rhythmHepatomegalyDx: Large VSD, Heart failure, Failure to thriveDefinite Rx: early surgeryAlternative Rx: Drugs first?
SS/EBM/Intro/2010
Medical students:(Background question)
What is VSD?How to Dx?What are symptoms & signs of CHF in infants with L-R shunt?What is the treatment?
SS/EBM/Intro/2010
House officers(Foreground question)
In infants with large VSD and CHF, would administration of digoxin or other inotropic agent delay the need for surgery?
SS/EBM/Intro/2010
Foregroundquestions
Backgroundquestions
Experience with condition
SS/EBM/Intro/2010
In neonates born to mothers with history of herpes simplex infection, does the administration of IVIG (intravenous immunoglobulin) reduce the possibility of neonatal herpes?
Other example
SS/EBM/Intro/2010
In women with history of eclampsia, would administration of low-dose aspirin (compared with no aspirin) during pregnancy prevent eclampsia?
Other example
SS/EBM/Intro/2010
Examples of clinical questions in practice
SS/EBM/Intro/2010
Example: Etiology
P I C O
“In premature infants …
…is mode
of delivery
…
…a risk factor for the develop
mnt HMD?
SS/EBM/Intro/2010
Example: Diagnosis
P I C O
“In patients
with suspect
edmalaria
…can rapid test
…compare
dwith microsco
peexam
…effectively establish diagnosis?
SS/EBM/Intro/2010
Example: Therapy
P I C O
“For px with
StevensJohnson syndro
me
will early
IVImmuno
-globulin
(IVIG)
…when compared
withno IVIG
…prevent severe
complica-tions?
SS/EBM/Intro/2010
Example: Prognosis
P I C O
“For px with SLE
…wouldhistory
ofheart failure
…compared with no history of HF
…worsenthe
prognosis?
SS/EBM/Intro/2010
Four elements of good clinical
question: PICOThe Patient or ProblemThe InterventionComparative intervention The Outcome
Domain
Determinants
Outcome
SS/EBM/Intro/2010
Four elements of a well constructed clinical
question: PICO
P I C O
The maininterventionconsidered
The alternativeto compare
with theintervention
Outcomeexpected from this
intervention?
Descriptionof patient
or problem
B e b r i e f a n d s p e c i f i c
SS/EBM/Intro/2010
Remember (1)Not all clinical questions contain 4 elements, depending on the nature of the condition being asked.
Examples: In post-menopausal women on hormone
replacement therapy, does addition of vitamin X reduce the likelihood of developing hip fracture? (PIO)
In patients with thalassemia HbE disease, what is the prevalence of single gene mutation? (PO)
SS/EBM/Intro/2010
Remember (2)In the PICO context, Intervention does not necessarily mean TREATMENT or PREVENTION, but may be: A diagnostic test (for diagnosis)
• In a patient with solitary thyroid nodule, does ultrasound exam, compared with needle biopsy, differentiate malignant from benign tumor?
A risk factor (for etiology, prognosis)• Is poor fiber diet a risk factor for the
development of colo-rectal cancer? A condition in the patient himself (for
prognosis)• In patient with SLE, would the history of
cardiac failure, compared with no failure, worsen the long-term prognosis?
SS/EBM/Intro/2010
Relevance: Type of Evidence
POE: Patient-oriented evidence mortality, morbidity, quality of
lifeDOE: Disease-oriented evidence pathophysiology,
pharmacology, etiology
SS/EBM/Intro/2010
Comparing DOEs and POEMs
Prostatescreening
PSA screeningdetects prostate
Ca. early
? whether PSAscreening mortality
DOE exists, butPOEM unknown
AntiarrhythmicTherapy
Antihypertens.Therapy
Drug A PVCOn ECG
Drug X BP Drug X mortality
Drug A > mortality
DOE & POEMcontradicts
POEM agreesWith DOE
Example DOE POEM Comment
SS/EBM/Intro/2010
IISearching the
evidence
SS/EBM/Intro/2010
Examples of on-line Journals / Databases
http://bmj.comhttp://adc/bmjjournals.comMEDLINE/PubMedEMBASEMDConsultAAP Journal ClubCochrane Library
SS/EBM/Intro/2010
Note: Spelling (American / British), terminologyFollow rigidly the instructions of each website
Examples:“Host vs graft reaction” AND managementhemosiderosis AND thalassemia OR thalassaemia“breast cancer” OR “Ca mammae” AND immunoglobulin OR IVIG
Use keywords for searching
SS/EBM/Intro/2010
IIIAppraising the
evidence:VIA
SS/EBM/Intro/2010
Validity: In Methods section:
design, sample, sample size, eligibility criteria (inclusion, exclusion), sampling method, randomization method, intervention, measurements, methods of analysis, etc
Importance: In Results section
characteristics of subjects, drop out, analysis, p value, confidence intervals, etc
Applicability: In Discussion section + our patient’s characteristics, local setting
VIA
SS/EBM/Intro/2010
Validity - other approach: RAMMbo
Recruitment: sampling methods, eligibility criteria, sample size Allocation: randomization? concealment? Maintenance: many drop outs? Measurement
blinded – RCT, Dx testobjective – validity & reliability
Can be applied for all designs with necessaryAdjustment according to nature of the design
SS/EBM/Intro/2010
Were the subjects randomized?Were all subjects received similar treatment?Were all relevant outcomes considered?Were all subjects randomized included in the analysis?Calculate CER, EER, RRR, ARR, and NNTWere study subjects similar to our patients in terms of prognostic factors?
Example: Critical appraisal for therapy
SS/EBM/Intro/2010
Hierarchy of evidence
Meta-analysis of RCT
Large RCT
Small RCT
Non-Randomized trials
Observational studies
Case series / reports
Anecdotes, expert, consensus
Level 1
Level 2
Level 3
Level 4
A
B
C
RecWeight ofScientific Scrutiny
SS/EBM/Intro/2010
Implementation of EBM practice:
How to get started 1. Teaching EBM in medical schools / PPDS
Easier than to change the already existing attitude Most important May be included in formal curricula or
integrated in existing activities: ward rounds, on calls, case presentations, group discussions, journal clubs, etc
2. Workshop for teaching staff 3. Workshop for practitioners, incl. nurses
SS/EBM/Intro/2010
Resistance to EBM teaching
& learning Rudimentary skill in critical
appraisal / methodological skill Limited resources, esp. time factor Lack of high quality evidence Skepticism toward evidence-based
practice ‘Happy’ with current practice
SS/EBM/Intro/2010
Development of EBM practice
Passive diffusion model Active dissemination model Coordinated implementation
model: Patients & community Health administrators Public policy makers Clinical policy makers
SS/EBM/Intro/2010
SS/EBM/Intro/2010
SS/EBM/Intro/2010
TheEBMCycle
PatientWith problem
FormulateIn answerable
question
Search theevidence
Critically Appraise
The evidence
ApplyThe evidence
SS/EBM/Intro/2010
Accessible population
(time, place)
Usu. Based on practicalpurposes
Appropriatesampling technique
[Non-response, drop outs,withdrawals, loss to follow-up]
Target population(Domain)
(demographic, clinical)
IntendedSample
[Subjects selectedfor study]
Actualstudy
subjects
Subjectscompletedthe study
Your patient is here!
SS/EBM/Intro/2010
Criticism to EBMEBM makes expensive medical careEBM cannot be implemented in developing countriesEBM is costly and time consumingEBM ignore pathophysiology & reasoningEBM ignore experience and clinical judgmentEB-guidelines etc interfere with professional autonomy
SS/EBM/Intro/2010
Criticism to EBM
EBM makes expensive medical care
Cf:Routine antibiotics for ARTI & diarrheaLiberal indication for C-sectionUnnecessary sophisticated procedures / examsUnnecessary / harmful treatment: steroid for recurrent cough
SS/EBM/Intro/2010
Criticism to EBM
EBM cannot be implemented in developing countries
By definition EBM is implemented if it is implementable (patient’s preference and local condition) – for the benefit of the patients and the community
SS/EBM/Intro/2010
Criticism to EBM
EBM is costly and time consumingEBM does requires facilities at the cost of quality medical care!Cost benefit ratio should be assessed in individual and community levels
SS/EBM/Intro/2010
Criticism to EBM
EBM ignores pathophysiology & reasoning
EBM encourages clinical reasoning in the light of valid and important evidence
Pathophysiology and reasoning should be seen as hypothesis and should end-up in empirical evidence
SS/EBM/Intro/2010
Criticism to EBMEBM ignore experience and clinical
judgment
Personal experience and clinical judgment are by no means can be eliminatedEBM encourage detailed and systematic documentation of experience and judgmentSubjective experience should be, whenever possible, translated into more objective measures
SS/EBM/Intro/2010
Criticism to EBM
EB-guidelines etc interfere with professional
autonomyProfessional conduct (competence, altruism, openness, collegiality, ethics) is encouraged in EBMEvery physician should develop their own practice attitude based on his/her profess-ionalism, valid evidence, and patient’s valuesDevelopment of clinical guidelines and other standards of care should be seen as a guide and implemented according to clinical setting
SS/EBM/Intro/2010
Barriers to the implementation of
Evidence-Based Medicine
“It takes too long.”
“Possibly a limitation
to my clinical
freedom.”“It questions my
professional
autonomy.”
SS/EBM/Intro/2010
Advantages of EBMEncourages reading habitImproves methodological skill (and willingness to do research?!)Encourages rational & up to date management of patientsReduces intuition & judgment in clinical practice, but not eliminates themConsistent with ethical and medico-legal aspects of patient management
SS/EBM/Intro/2010
End result
Self directed, life-long learning attitude
for high quality patient care
SS/EBM/Intro/2010
Conclusion
EBM is nothing more than aframework of systematic use ofcurrent valid study results relevant to our patient
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Evidence-based CardiologyEvidence-based PediatricsEvidence-based Ob-GynEvidence-based Dentistry Evidence-based Nursing Evidence-based Health PolicyEvidence-based Health Technology AssessmentEvidence-based Decision MakingEvidence-based Health Performance IndicatorsEvidence-based Clinical AuditEvidence-based Risk Management …….Evidence-based Everything!!!
SS/EBM/Intro/2010
In God we trustAll others must have
evidence
SS/EBM/Intro/2010
Remember, however …...
Medicine is the science of uncertainty
and the art of probabilities