3 Evidence-based Medicine versusOpinion-based medicineExperience-based medicinePower-based medicineHope-based medicineLogic-based medicineErratic-based medicine
4 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)4
5 Evidence-based Medicine Medicine-based evidencePragmatic researchOutcome researchRelated withmorbidity, mortality, quality of life
6 Value Quality Cost = Morbidity Mortality QoL Patient Satisfaction HealthStatusQualityValue=Cost
7 Diagnosis Patient with complaint History Physical Simple test Specific test: If the test (+) what is the probability that the patient has the disease?Yes or no answerPredictive value is the most importantThe spectrum of the presentations must resemble that in practice
8 Treatment Patient with certain diagnosis: best treatment? Is drug X more effective than Y?Focus on the clinical outcome, rather than its explanation (biomolecular markers, etc)Yes or no outcome most usefulNot in studies with “idealized” subjectsPx with DM are frequently have hypercholesterolemia, obese, hypertension, etc
9 Prognosis Usually in cohort studies To inform about the fate of the patientAbsolute risk is more important than relative riskAbsolute: Your risk of having second stroke in 1 year is 30%Relative: Your risk of having second stroke in 1 year is 2 times than in non-smokers (RR = 2)
10 EBM & Clinical Epidemiology Fletcher & Fletcher: CE = The application ofepidemiologic 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
11 Previous practice: 6 yrs medical education Problems with patients: Dx, Rx, Px40-50 yrsmedical practiceConsultants, colleaguesTextbooksHandbooksLecture notesClinical guidelinesCME, seminars, etcJournalsUsu. see only Results section,or even worse, Abstract section
12 Trust meIn my experience ….LogicallyTextbook, handbook, capita selecta
13 The results…. “Opinion-based medicine” Steroid inj. in prematures to prevent RDSRoutine episiotomyRoutine circumcisionAntibiotics for flu-like syndromeUse of immunomodulators“Skin test” before antibiotic injectionRoutine chest X-ray for pre-op preparationCT scan after minor head traumaetc ……
14 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
15 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 evidenceMeta-analyses, clinical trials, and all study results should be critically appraisedKeyword for EBM:Methodological skill to judge the validityof study reports (Re. Andersen B: Methodo-logical errors in medical research, 1989)
17 There are two most difficult to understand: womanand ....statistics
18 Dean, Harvard Medical School to students: “We believe that 50% of what we are teaching to you now will prove to be false 5 years later; the problem is that we do not know which 50%”
19 WHY EBM? 1 Information overload 2 Keeping current with literature 3 Our clinical performance deteriorates with time (“the slippery slope”)4 Traditional CME does not improve clinicalperformance5 EBM encourages self directed learning process which should overcome the above shortages
20 $ THE SLIPPERY SLOPE 100% Relative % of remaining knowledge Years after graduationTHE SLIPPERY SLOPE
21 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.Antman EM, Lau J, Kupelnick B, Mosteller F, Chalmers TC: A comparison of results of meta-analyses of randomised control trials and recommendations of clinical experts. JAMA 1992;268:240-8.Then I show two slides from their article, showing the lag in recommending thrombolytics and the lag in de-recommending lidocaine for myocardial infarction.
22 Steps in EBM practice VIA Formulate clinical problems in answerable questionsSearch the best evidence: use internet or other on-line database for current evidence3. Critically appraise the evidence forValidity (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 performanceVIA
23 Main areaDiagnosis (Determination of disease or problem) Treatment (Intervention necessary to help the patient) Prognosis (Prediction of the outcome of the disease)
25 A 2-year old boy presented with 6-day high fever, conjunctival injection without secretion, skin rash> blood test shows leukocytosis, high ESR, CRP +++. He was suspected to have Kawasaki disease. The pediatrician is aware of the use of immunoglobulin to prevent coronary involvement, but uncertain about the dosage or recent developments.
26 Medical students: (Background question) What is Kawasaki disease?What is the etiology?How it is diagnosed?What is the treatment of choice?Complications?
27 House officers (Foreground question) In a child with KD, would immunoglobulin treatment, compared with no immunoglobulin, reduce the chance to develop coronary complication?
28 ForegroundquestionsBackgroundExperience with condition
29 Other examplesIn women with history of eclampsia, would administration of low-dose aspirin during pregnancy prevent eclampsia? (Prevention)In young women with solitary thyroid nodule, can USG, compared with biopsy, differentiate between benign from malignant? (Diagnosis)In women systemic lupus erythematosus, is history of congestive heart failure, compared with no heart failure, worsen the prognosis? (Prognosis)
30 Four elements of good clinical question: PICO The Patient or ProblemThe Intervention / IndexComparative intervention (if relevant)The Outcome
31 Four elements of a well constructed clinical question: PICO The maininterventionconsideredThealternativeto comparewith theOutcomeexpectedfrom thisintervention?Descriptionof patientor problemB e b r i e f a n d s p e c i f i c
32 Do all clinical questions contain 4 elements of PICO? NoThe C implies in the question - PIODoes temulawak increase appetite in undernourished children?Asking prevalence – POWhat is the prevalence of abnormal gene XYZ in patients with b-thalassemia?
33 Relevance: Type of Evidence POE: Patient-oriented evidencemortality, morbidity, quality of lifeDOE: Disease-oriented evidencepathophysiology, pharmacology, etiology
35 Comparing DOES and POEMs ProstatescreeningPSA screeningdetects prostateCa. early? whether PSAscreening mortalityDOE exists, butPOEM unknownAntiarrhythmicTherapyAntihypertens.Drug A PVCOn ECGDrug X BPDrug X Drug A >DOE & POEMcontradictsPOEM agreesWith DOEExampleDOEPOEMComment
38 VIA Validity: In Methods section: design, sample, sample size, eligibility criteria (inclusion, exclusion), sampling method, randomization method, intervention, measurements, methods of analysis, etcImportance: In Results sectioncharacteristics of subjects, drop out, analysis, p value, confidence intervals, etcApplicability: In Discussion section + our patient’s characteristics, local setting
39 Critical appraisal for therapy Example:Critical appraisal for therapyWere 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?
40 Hierarchy of evidence Level 1 Level 2 Level 3 Level 4 Rec BCRecWeight ofScientificScrutinyLevel 1Level 2Level 3Level 4Meta-analysis of RCTLarge RCTSmall RCTNon-Randomized trialsObservational studiesCase series / reportsAnecdotes, expert, consensusFor complete description see
41 Implementation of EBM practice: How to get started 1. Teaching EBM in medical schools / PPDSEasier than to change the already existing attitudeMost importantMay be included in formal curricula or integrated inexisting activities: ward rounds, on calls, casepresentations, group discussions, journal clubs, etc2. Workshop for teaching staff3. Workshop for practitioners, incl. nurses
42 Resistance to EBM teaching & learning Rudimentary skill in critical appraisal /methodological skillLimited resources, esp. time factorLack of high quality evidenceSkepticism toward evidence-based practice‘Happy’ with current practice
44 The EBM Cycle Patient With problem Apply Formulate The evidence In answerablequestionApplyThe evidenceAppraiseThe evidenceSearch theevidence
45 Criticism to EBM EBM makes expensive medical care EBM 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
46 Advantages of EBM Encourages reading habit Improves 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
47 End result Self directed, life-long learning attitude for high quality patient care
48 Conclusion EBM is nothing more than a framework of systematic use of current valid study resultsrelevant to our patient