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Evidence-Based Medicine

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Presentation on theme: "Evidence-Based Medicine"— Presentation transcript:

1 Evidence-Based Medicine
(”Bringing research evidence into practice”) Sudigdo Sastroasmoro Clinical Epidemiology and Evidence-based Medicine Unit FMUI – CMH, Jakarta

2 5-day workshop 3-day workshop 2-day workshop

3 Evidence-based Medicine
versus Opinion-based medicine Experience-based medicine Power-based medicine Hope-based medicine Logic-based medicine Erratic-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 a an significant risk factor for SIDS (sudden infant death syndrome) 4

5 Evidence-based Medicine
Medicine-based evidence Pragmatic research Outcome research Related with morbidity, mortality, quality of life

6 Value Quality Cost = Morbidity Mortality QoL Patient Satisfaction
Health Status Quality Value = 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 answer Predictive value is the most important The 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 useful Not in studies with “idealized” subjects Px with DM are frequently have hypercholesterolemia, obese, hypertension, etc

9 Prognosis Usually in cohort studies
To inform about the fate of the patient Absolute risk is more important than relative risk Absolute: 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 of epidemiologic principles in problems encountered in clinical medicine Sackett et al: CE = The basic science for clinical medicine Much resistance by experts EBM: In principle – no one disagree All major medical journals have adopted EBM Centers for EBM all over the world

11 Previous practice: 6 yrs medical education Problems with patients:
Dx, Rx, Px 40-50 yrs medical practice Consultants, colleagues Textbooks Handbooks Lecture notes Clinical guidelines CME, seminars, etc Journals Usu. see only Results section, or even worse, Abstract section

12 Trust me In my experience …. Logically Textbook, handbook, capita selecta

13 The results…. “Opinion-based medicine”
Steroid inj. in prematures to prevent RDS Routine episiotomy Routine circumcision Antibiotics for flu-like syndrome Use of immunomodulators “Skin test” before antibiotic injection Routine chest X-ray for pre-op preparation CT scan after minor head trauma etc ……

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 evidence Meta-analyses, clinical trials, and all study results should be critically appraised Keyword for EBM: Methodological skill to judge the validity of study reports (Re. Andersen B: Methodo-logical errors in medical research, 1989)

16 When doctors meet numbers .....
Y= a + b1x1 + b2X2 + b3X3 + ……. + bixi ?? When doctors meet numbers ..... $ 6,000 Yesss!!!

17 There are two most difficult to understand:
woman and .... 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 clinical performance 5 EBM encourages self directed learning process which should overcome the above shortages

20 $ THE SLIPPERY SLOPE 100% Relative % of remaining knowledge
Years after graduation THE 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 questions 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 patient 5. Evaluate our performance VIA

23 Main area Diagnosis (Determination of disease or problem) Treatment (Intervention necessary to help the patient) Prognosis (Prediction of the outcome of the disease)

24 (I) Formulating clinical questions

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 Foreground questions Background Experience with condition

29 Other examples In 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 Problem The Intervention / Index Comparative intervention (if relevant) The Outcome

31 Four elements of a well constructed clinical question: PICO
The main intervention considered The alternative to compare with the Outcome expected from this intervention? Description of patient or problem B 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?
No The C implies in the question - PIO Does temulawak increase appetite in undernourished children? Asking prevalence – PO What is the prevalence of abnormal gene XYZ in patients with b-thalassemia?

33 Relevance: Type of Evidence
POE: Patient-oriented evidence mortality, morbidity, quality of life DOE: Disease-oriented evidence pathophysiology, pharmacology, etiology

34 POEM Patient-Oriented Evidence

35 Comparing DOES and POEMs
Prostate screening PSA screening detects prostate Ca. early ? whether PSA screening  mortality DOE exists, but POEM unknown Antiarrhythmic Therapy Antihypertens. Drug A  PVC On ECG Drug X  BP Drug X  Drug A > DOE & POEM contradicts POEM agrees With DOE Example DOE POEM Comment

36 II Searching the evidence

37 III Appraising the evidence: VIA

38 VIA 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

39 Critical appraisal for therapy
Example: Critical appraisal for therapy 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 NNT Were study subjects similar to our patients in terms of prognostic factors?

40 Hierarchy of evidence Level 1 Level 2 Level 3 Level 4 Rec
B C Rec Weight of Scientific Scrutiny Level 1 Level 2 Level 3 Level 4 Meta-analysis of RCT Large RCT Small RCT Non-Randomized trials Observational studies Case series / reports Anecdotes, expert, consensus For complete description see

41 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

42 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


44 The EBM Cycle Patient With problem Apply Formulate The evidence
In answerable question Apply The evidence Appraise The evidence Search the evidence

45 Criticism to EBM EBM makes expensive medical care
EBM cannot be implemented in developing countries EBM is costly and time consuming EBM ignore pathophysiology & reasoning EBM ignore experience and clinical judgment EB-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 patients Reduces intuition & judgment in clinical practice, but not eliminates them Consistent 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 results relevant to our patient

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