An introduction to Evidence-Based Medicine (critical thinking in medicine)

1. An introduction toEvidence-Based Medicine(critical thinking in medicine) Akbar Soltani. MD,MSc Tehran University of Medical Sciences (TUMS) Shariati Hospital www.soltaniebm.com www.ebm.ir www.avicennact.ir

2. Educational Activities • Whole spectrum of the medical profession • From 2000 to 2006 we had more than 200 lectures in EBM, MDM, Methodology, • From 2006 to 2007 we had more than 50 lectures in CT • More than 7000 slides have been prepared • 10 books have been compiled • www.soltaniebm.com or www.ebm.ir and www.avicennact.ir

8. Some assumptions • You, the audience, between you know much more than I do about this • Lao Tzu said: “Those who know do not speak/Those who speak do not know.” • Kafka: What a silence had been established in the world if every person talk correlated with his/her knowledge

9. Workshop objectives • Problems of conventional medicine • Definition and philosophy of EBM/IM • Different concepts such as • answerable question, systematic review, NNT,NNH,… • Search methods • Most popular EBM data bases • Critical appraisal skills

11. What is the best way of walking? What is the best way of thinking? What is Critical Thinking? fshahrtash@gmail.com

12. Agenda • Definitions: Science and EBM • Dimensions of the problem • Information management (mastery) • Limitations of current clinical practice • Heuristic and errors • Problems of communication • EBM

13. Definition: • Science is devoted to formulating and testing naturalistic explanations for natural phenomena. It is a process for systematicallycollecting and recording data about the physical world, then categorizing and studying the collected data in an effort to infer the principles of nature that best explain the observed phenomena.72 Nobel laureates. (From the Amicus Curiae presented in the US Supreme Court Case of Edwards vs Agullard, 1986)

14. Philosophers in science:

15. Trace back to the development of EBM. • 1972:Archie Cochrane told about the role of randomized control trial in scientific medicine. • 1980's: Dave Sackett • 1990s :The term was generated by Gordon Guyatt from McMaster University

16. Trace back to the development of EBM

17. What evidence-based medicine is • “The conscientious (careful), explicit (clear, unambiguous) and judicious (sensible) , use of current best evidence in making clinical decisions about the care of individual patients.” Sackett et al, 2000

18. What evidence-based medicine is: The practice of EBM is the integration of • Individual clinical expertise with the • Best available external clinical evidence from systematic research. and • Patient’s values and expectations Sackett DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS: Evidence based medicine: what it is and what it isn’t. BMJ 1996;312:71-2.

19. I.Individual Clinical Expertise: • Experience: Relates to what we’ve done and to knowledge. • “An expert is a person who has made all the mistakes that can be made in a very narrow field” (Niels Bohr) • Clinical skills • Clinical judgment • Vital for determining whether the evidence applies to the individual patient at all and, if so, how

20. Patient seen in practice Matches research result to specific patients Hypothesis generating ? Clinical judgment Outcomes research Confirms or denies hypothesis

22. II. Best External Evidence: • From real clinical research amongintact patients. • Has a short doubling-time (10 years). • Replaces currently accepted diagnostic tests and treatments with new ones that are more powerful, more accurate, more efficacious, and safer.

23. III. Patients’ Values & Expectations • Have always played a central role in determining whether and which interventions take place

24. clinical expertise Current best evidence Patient preferences A model for evidence-based clinical decisions Sackett et al, 2000 Bayesian approach: background knowledge + evidence= decision making

25. Clinical Setting Model of Evidence-Based Medicine

26. Conventional medicine Expertise (intuition…) Pathophysiology, references, tradition… Patient value

27. Agenda • Definitions: Science and EBM • Dimensions of the problem • Information management (mastery) • Limitations of current clinical practice • Heuristic and errors • Problems of communication • EBM

28. Why Is It So Hard to BeUp-to-date? • The database of the National Library of Medicine MEDLINEhas approximately 6 million references from 4.000 journals with about 400.000 new entries added each year. • Doubling time of biomedical science is about 20 months in 2001

29. Increasing Knowledge

30. How many original articles should a specialist read each week to remain up to date in his/her own field only ? • 5 • 10 • 20 • 40 • 100 Dr.S.Naserimoghaddam

31. How many original articles should a specialist read each week to remain up to date in his/her own field only ? • 5 • 10 • 20 • 40 • 100 The story is different for a generalist: 17 /day! Dr.S.Naserimoghaddam

32. Thrombolytic Therapy & MI mortality RCT23 Patients 1960 Odds Ratio 2 0.5 1  Treatment Control 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

33. Thrombolytic Therapy & MI mortality Cumulative Year RCTs Pts 1960 1965 Odds Ratio 2 0.5 1 1 23 2 65 3 149 4 316 7 1793      Treatment Control Antman JAMA 92

34. Thrombolytic Therapy & MI mortality Cumulative Year RCTs Pts 1960 1965 1970 1975 1980 1985 1990 Odds Ratio 2 0.5 1 1 23 2 65 3 149 4 316 7 1793 10 2544 11 2651 15 3311 17 3929 22 5452 23 5767 27 6125 33 6571 65 47185 70 48154       p < 0.01       p < 0.001    p < 0.00001  Treatment Control Antman JAMA 92

35. Thrombolytic Therapy & MI mortality Cumulative Year RCTs Pts 1960 1965 1970 1975 1980 1985 1990 Textbook Recommendations Rout Specif Exp NOT Odds Ratio 2 0.5 1 1 23 2 65 3 149 4 316 7 1793 10 2544 11 2651 15 3311 17 3929 22 5452 23 5767 27 6125 33 6571 65 47185 70 48154  21 5 10 2 8 7 8 12 4 3 1 1    1 1 2 8 7 2   p < 0.01    1 1 1 2 8 1    p < 0.001  5 15 6   p < 0.00001  Treatment Control Antman JAMA 92

36. Antman JAMA 92

37. Some parts of 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 tenyears after it’s been shown to be useless. • Different textbooks, different recommendations. • Textbooks are fact or opinion? • Textbooks are appraisable? 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

39. Worse with “duration in practice” The Prognosis of Ignorance is Poor

41. Interesting Example Dr Naserimoghaddam

42. 182 Health authorities selected • 2 Articles: 1 on cardiac rehabilitation 1 on breast Ca screening • Results of each presented in 4 ways: • RRR (Relative Risk Reduction) • ARR (Absolute Risk Reduction) • PEFP (Proportion of Event Free Patients) • NNT ( Number Needed to Treat) Evidence based purchasing: understanding results of clinical trials and systematic reviews T Fahey, S Griffiths, T J Peters. BMJ 1995;311:1056-1059 (21 October) Dr Naserimoghaddam

43. They were told that these were the results of 4 articles on each topic • Question: According to which set of data you may choose to adopt the method as part of your regional practice policy? Evidence based purchasing: understanding results of clinical trials and systematic reviews T Fahey, S Griffiths, T J Peters. BMJ 1995;311:1056-1059 (21 October) Dr Naserimoghaddam

44. Interesting Results ! Evidence based purchasing: understanding results of clinical trials and systematic reviews T Fahey, S Griffiths, T J Peters. BMJ 1995;311:1056-1059 (21 October) Dr Naserimoghaddam

45. Only 3 noted that all 4 sets of data are the same! • None were clinicians! Evidence based purchasing: understanding results of clinical trials and systematic reviews T Fahey, S Griffiths, T J Peters. BMJ 1995;311:1056-1059 (21 October) Dr Naserimoghaddam

46. Hypothesis? Sample size estimation None!

47. Failure to detect a difference = Equivalence?

48. Assume non-inferiority if the lower limit of 95% CI is less than –5%, N=904 per group!

49. Percent correct answers for knowledge questions

50. Agenda • Definitions • Dimensions of the problem • Information management (mastery) • Limitations of current clinical practice • Heuristic and errors • Problems of communication • EBM