Evidence Based Medicine


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Evidence Based Medicine

  1. 1. Why Evidence Based Medicine<br />Dr. T.M.A. Abdelmoniem<br />
  2. 2. Is the EBM a Recent Issue ?<br />The EBM has a deep roots and some says that it has origins in ancient Greece, and others say that it returns to the ancient Chinese.(Sackett et al; BMJ.1996;312)<br />EBM is a New Start for Old Beginnings<br />
  3. 3. History of EBM?<br />In spite that the testing the efficacy of medical interventions started in the 11th century, the Scottish epidemiologist Prof. Archie Cochrane increased the acceptance for the concepts of evidence based practice through his book Effectiveness and Efficiency: Random Reflections on Health Services ( 1972)<br />His Work was highly appreciated and the Cochrane’s Collaboration for EBM was named after him<br />
  4. 4. What is Evidence Based Medicine?<br />Evidence Based Medicine is the application of the best available evidence that is obtained from the well designed scientific researches to the medical practice and decision making. It ranks the evidences according to its strength.<br />(Timmermans and Mauck ;2005 Health Affairs)<br />
  5. 5. Classifications<br />EBM<br />Evidence Based Individual Decision Making<br />Evidence Based Guidelines<br />
  6. 6. Evidence Based Guidelines:<br />It application of the Evidence Based Medicine in the health organizations, to regulate and guide the practice.<br />Evidence Based Individual Decision Making :<br />It focus on the practitioner and how to build up his decisions according to the best evidence.<br />
  7. 7. Classifications of Evidence Levels<br />Ia: Meta-analysis of Randomized controlled trials.<br />Ib: At least one Randomized controlled trial.<br />IIa: At least one well-designed controlled study without randomization.<br />IIb:At least one other type of well-designed Experimental study.<br />
  8. 8. Classifications of Evidence Levels(cont.)<br />III: well-designed non-experimental descriptive studies.<br />IV: Expert committee reports or opinions and/or clinical experience of respected authorities.<br />
  9. 9. Evidence Pyramid<br />
  10. 10. Why EBM?<br />EBM aims to enhance the quality and accountability for the medical practice.<br />It creates common concepts and unify the language for implementation of research into practice.<br />Promote a life long learning process by continuous searching for best evidence.<br />
  11. 11. Evidence Based Decision Making<br />Clinical Decision Making<br />
  12. 12. Meta-Analysis<br />Defined as getting a conclusion from the previously published researches through statistical analysis of quantitative systemic combination of its results.<br />This type of studies is gaining the popularity specially when the speaking is about efficacy of treatments that have previous clinical trials.<br />
  13. 13. Strengths of Meta-Analysis<br />
  14. 14. Combining the results of the previous studies strengths the evidence and overcome the defects in to small or limited studies.<br />Provide a conclusion including the interrelationships between this different studies.<br />Reliable and Systematic<br />Define the Quality of researches.<br />
  15. 15. Difficulties of Meta-Analysis<br />
  16. 16. Integration the results of different studies with different levels of error my affect the results of the study.<br />Combining the evidence from studies using different methodologies to answer the same question<br />
  17. 17. Experimental Studies<br />
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  19. 19. Advantages of Experimental studies<br />It is objective not subjective<br />Has a predictive value<br />Can be generalized<br />Define a cause effect relationship<br />Has least Bias<br />
  20. 20. Disadvantages of Experimental researches<br />Difficult to be applied in certain conditions as in cancer patients it is difficult to have no treatment arm.<br />Limitation of the research limit its generalization.<br />Have strict criteria that limit self reflection<br />
  21. 21. Observational Studies<br />
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  23. 23. Advantages of Cohort Study<br />More accurate<br />Used for estimation of incidence rates as well as the risk of diseases.<br />Can be used to study more than one outcome.<br />
  24. 24. Disadvantages of Cohort Study<br />It is time consuming<br />Expensive<br />Exposed to heavy losses during follow up.<br />Can not be used to study rare diseases.<br />
  25. 25. Advantages of Case-Control Study<br />Best in studying rare diseases.<br />Not time consuming<br />Needs less money and personnel.<br />
  26. 26. Disadvantages of Case-Control Studies<br />Has an appreciable degree of bias in cases and controls as well as in recall.<br />Unsuitable for estimation of the incidence and prevalence of disease.<br />Study one outcome only.<br />
  27. 27. Advantages of Cross-Sectional Study<br />Suitable for studying the prevalence and risk factors of diseases.<br />Not time consuming<br />Cheap<br />No losses in follow up<br />
  28. 28. Disadvantages of Cross-Sectional Study<br />Unsuitable for measuring the incidence.<br />Unsuitable for rare diseases.<br />Unable to detect cause effect relationship.<br />
  29. 29. Descriptive Studies<br />
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  31. 31. Characteristics of Descriptive Studies<br />Suitable in studying the frequency of diseases<br />Suitable for tracing the natural history and characteristics of disease.<br />Can not drive a conclusion about the relations of the different variables.<br />
  32. 32. Criteria of Good Research<br />
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  34. 34. Strength<br />It is the validity of the research in achieving its goal.<br />Validity may be:<br />Internal: means that the detected difference in the dependent variable is a result of the independent variables.<br />External: means that the results of this research can be generalized outside the experiment settings.<br />Conclusion: the relation between the treatment and the outcome is identified<br />
  35. 35. Consistency<br /><ul><li>It is the reliability of the measurements and it means the ability of an instrument to measure twice in the same conditions without difference in the outcomes measured.
  36. 36. An example: a test is reliable when an individual’s score is similar for the same test twice.</li></li></ul><li>Firmness<br />Adherence to the protocol of the study<br />Suitable methodology and analysis.<br />Validity and Reliability in conducting research<br />Proper presentation of the results<br />
  37. 37. Thank You<br />