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EBM PowerPoint Presentation

EBM

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EBM

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  1. EBM Dr Adrian Burger 20 March 2007

  2. EBM Intro • Evidence based guidelines • Evidence based care paths • Evidence based Questions • Evidence based Solutions • Evidence based ……

  3. Shift_Expectations • Whether to implement • How to - sensibly - efficiently - avoid misconceptions • EBM CONCEPTS ARE NOW UNAVOIDABLE

  4. (Mis)Concepts • EBM DOES NOT = RCT • Cannot rely solely on research from RCT - <14% are RCT - Observational studies overlooked - undervalued patient preferences, clinical circumstances, expertise

  5. Clearly define your question Thorough literature search Critically appraise the quality of the evidence Critically assess the applicability Balanced application What You Need to Do

  6. The evidence cycle

  7. Balanced application of the evidence

  8. Clinical circumstances • Clinical expertise and judgment • Assumes physician competence on basis of - clinical experience - development of clinical instincts

  9. Patient preferences • Individualizes needs • Takes into account patients’ - experiences - values - expectations

  10. Research evidence • Ask the question • Acquire the information • Appraise the quality • Apply the results • Act on the patient

  11. Own research, reviews - Guide to the Medical Literature Online - Cochrane Database - Best Bets EBM Resources

  12. Levels of Evidence • Hierarchy of evidence RCT Controlled observational studies Uncontrolled studies and opinion

  13. Studies: First Question • Is the study - investigating results of a treatment? Therapeutic Study - outcome of a disease? Prognostic Study - Diagnostic test? - Developing an economic model/decision analysis?

  14. Studies: Categorize the study • Level 1 RCT or systematic review of RCTs • Level 2 Prospective cohort, poor quality RCT, systematic review • Level 3 Case control, retrospective cohort, systematic review of level 3 studies

  15. Categorize the studies 2 • Level 4 Case series • Level 5 Expert opinion

  16. Level One and Two

  17. Level 3-5

  18. Errors in Hypothesis Testing • Small sample studies - Type 2 Beta errors Probability of concluding that no difference exists when there is a difference Acceptable rate is 20% This equals a power of 80% If >20% then unacceptably high risk of false negatives

  19. Errors 2 • Type 1 or Alpha Error Concluding the results of a study are true when in fact it is due to chance or random sampling error Is an erroneous false positive Acceptable rate of 5%

  20. Power of a study • Probability of concluding a difference between two treatments when one actually does exist • Power = 1- Beta • Can be used before a study to determine study sample size • Can be used after a study to determine if negative findings true or just due to chance

  21. Article • Injury, 37, 302 – 306 Evidence-based Medicine: What it is and what it is not