Evidence based medicine Riga 2012-05-07


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Presentation on basics of EBM in Riga, Latvia.

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Evidence based medicine Riga 2012-05-07

  1. 1. Evidence based medicine Professor Janko Kersnik, MD, MSc, PhD Family doctor in a branch office Kranjska Gora, SloveniaHead of Family Medicine Department, Medical School Maribor Head of Research Department, Department of Family Medicine, Medical School Ljubljana President of Slovenian Family Medicine Society President of EURACT
  2. 2. Structure of the presentation1. Principles of EBM2. Demonstration in searching evidence3. Assessment of the evidence (paper)4. Information for group work: Exercise in assessment of evidence7. 5. 2012 EBM 2
  3. 3. Variation to the themes Evidence based medicines Scientific medicines Evidence based practices ...7. 5. 2012 EBM 3
  4. 4. Read thread of EBMs Patient dilemmas Ask clinical questions Acquire (search) evidences Apprise (assess) evidences Apply in everyday practices Act (monitor change)7. 5. 2012 EBM 4
  5. 5. Aim of the first parts To demonstrate how by using IT we can get answers to clinical questions.7. 5. 2012 EBM 5
  6. 6. Literatures http:// www.hsl.unc.edu/services/tutorials/ebm/ws http://medlib.bu.edu/tutorials/ebm/7. 5. 2012 EBM 6
  7. 7. By the end of the first part you wills Know how to set clinical questions Know key electronic databases (Medline, Cochrane, Clinical Evidence)s Know how to get them (Internet, CD, book)s Understand and value evidence for safe works Be able to use evidence for your everyday practice7. 5. 2012 EBM 7
  8. 8. What do we know on EBM?s Buzz groups – discuss in groups of three7. 5. 2012 EBM 8
  9. 9. What is EBM?s Evidence instead experience and eminences Use of IT in everyday practices An answer to patient demandss “New religion” which is changing our practice7. 5. 2012 EBM 9
  10. 10. What is EBM practice?s EBM is defined as an application of best research evidence in everyday patient care.s EBM is defined as clinical decision which is based on systematic search, assessment and application of evidence.7. 5. 2012 EBM 10
  11. 11. EBM-47. 5. 2012 EBM 11
  12. 12. Four steps in searchingevidence 1 2 3 47. 5. 2012 EBM 12
  13. 13. 1 Clinical questions To begin the EBM search process start with a well-developed and answerable question. A good clinical question will: – Save time when researching – Keep the focus directly on the patients need – Suggest the appropriate form that a useful answer may takes The clinical question will impact the entire EBM literature searching process.7. 5. 2012 EBM 13
  14. 14. Typical questionss Therapys Diagnosticss Prognosiss Preventions Health promotion….s What should I do for this patient?7. 5. 2012 EBM 14
  15. 15. PICO7. 5. 2012 EBM 15
  16. 16. Questionss Who is your patient?s What is the intervention?s What is the comparison?s What is the outcome?7. 5. 2012 EBM 16
  17. 17. Your patients In your 83-year old patient, who is 25 years treated for high blood pressure, which is well organized with the average blood pressure values below 140/90 mmHg, you have found at a regular check up an irregular heart rhythm, which is on the ECG proved atrial fibrillation. Does not have any other diseases, he is in good physical and mental condition. Since you do not have data on the beginning of this disorder, you have referred him to a cardiologist. He returns with the result, from which you read, that he has undergone unsuccessful cardio conversion. The patient prefers aspirin, which does not require any monitoring, over proposed warfarin. 7. 5. 2012 EBM 17
  18. 18. Patient dilemma s Shall we follow the guidelines or is there evidence that we can take into account patient preferences?7. 5. 2012 EBM 18
  19. 19. In small groups......define clinical question from your practice,…or define clinical question from the case of our 83- years old patient.7. 5. 2012 EBM 19
  20. 20. Clinical question in our cases Is treatment with aspirin (I) in the 83- year old patient with chronic atrial fibrillation (P) as effective as warfarin (C) in terms of prevention of stroke and total mortality and complications of treatment (O)?7. 5. 2012 EBM 20
  21. 21. Searching evidences Where do you search information?7. 5. 2012 EBM 21
  22. 22. Hierarchy of evidences Systematic reviewss Meta-analysess RCTs Prospective studiess Retrospective studiess Case reports7. 5. 2012 EBM 22
  23. 23. Types of studies (iz: Silagy and Haines, Evidence Based Practice in Primary Care, BMJ Books, 1998) O b s e rv a tio n a l E x p e r im e n ta lD e s c r ip tiv e A n a ly t i c a l U n c o n t r o lle d C o n tr o lle d C o h o rt C a s e -c o n tro l N o n - r a n d o m is e d R a n d o m is e d 7. 5. 2012 EBM 23
  24. 24. Sourcess Medlines Cochranes Clinical Evidence7. 5. 2012 EBM 24
  25. 25. MEDLINEs From 1966s Internet baseds Search; PubMed - http:// www.ncbi.nlm.nih.gov/pubmed/ (http:// www.ncbi.nlm.nih.gov/sites/entrez )s Usual termss Option “find related data; PubMed; related articles”s Option “Also try”s Options to copy in a file (Send to; File) or in own data base (Reference manager) 7. 5. 2012 EBM 25
  26. 26. Strategys Search; MeSH (Medical Subject Headings)s English termss Operators (and, not, or)s Limits (author, title, abstract, language)s “Find related articles”7. 5. 2012 EBM 26
  27. 27. http://www.ncbi.nlm.nih.gov/sites/entrez7. 5. 2012 EBM 27
  28. 28. 7. 5. 2012 EBM 28
  29. 29. COCHRANEs Systematic reviews, RCTs Internets Rigorous inclusion criterias Regular update7. 5. 2012 EBM 29
  30. 30. 7. 5. 2012 EBM 30
  31. 31. 7. 5. 2012 EBM 31
  32. 32. CLINICAL EVIDENCEs Book twice a years Relevant clinical questions7. 5. 2012 EBM 32
  33. 33. 7. 5. 2012 EBM 33
  34. 34. Find in Internet relevant papers forthe subject you are interested!Select one you want to apprise.7. 5. 2012 EBM 34
  35. 35. Search for our patients MeSH: warfarin aspirin stroke prevention not dabigatrans Limits – RCT or systematic reviews, – Not older than 5 years, – Human, – Male, older than 80 years, – English, – Free papers.7. 5. 2012 EBM 35
  36. 36. Search results for our patients We got 7 hits.s After reading titles and abstracts we were left with two of them: – Williams JE, Chimowitz MI, Cotsonis GA, Lynn MJ, Waddy SP; WASID Investigators.Gender differences in outcomes among patients with symptomatic intracranial arterial stenosis. Stroke. 2007 Jul;38(7):2055-62. Epub 2007 May 31. – Rash A, Downes T, Portner R, Yeo WW, Morgan N, Channer KS. A randomised controlled trial of warfarin versus aspirin for stroke prevention in octogenarians with atrial fibrillation (WASPO). Age Ageing. 2007 Mar;36(2):151-6. Epub 2006 Dec 15.7. 5. 2012 EBM 36
  37. 37. Conclusions for the first parts Searching can make funs There are simple tools availables Practice make expert7. 5. 2012 EBM 37
  38. 38. Appraisal (assessment/evaluation ofevidence)
  39. 39. Aims of the second parts What is medical literature?s What types of documents/papers do we know?s Sources of primary documentss Criteria for papers, guidelines, meta- analyses. Systematic reviews7. 5. 2012 EBM 39
  40. 40. Medical literatures Primary documents – primary (research) paper – diploma, masters, doctoral thesiss Secondary documents – review paper – meta-analysis – seminar work – guideliness Tertiary documents – textbook – handbook – congress proceedings 7. 5. 2012 EBM 40
  41. 41. Sources of primary documents s Specialist theses s Graduate theses s Maister theses s Doctoral tehses s Medical journals7. 5. 2012 EBM 41
  42. 42. Strengths and weaknesses of primary documentsStrengths Weaknessess Original, s Large number of unpublished work paperss Source of new s Evidence is mainly knowledge scattered overs Basis of scientific several journals development7. 5. 2012 EBM 42
  43. 43. Structure of primary documents Title s Resultss Abstract – Sample description – Key resultss Introduction – Additional analyses – “What was the problem?” “Why is this s Discussion problem interesting for – On methods a reader?” – On resultss Aims, hypothesis s Conclusionss Methods and patients s Acknowledgement – Methods s Financial disclosure – Patients - sampling – Study description s “Conflict of interest” – Data analysis s References s Appendices7. 5. 2012 EBM 43
  44. 44. External grading of “reliability”of the source – medical journals External reviewerss Indexeds On Medlines SCI: science citation index, SSCI: social science citation indexs IF: impact factor7. 5. 2012 EBM 44
  45. 45. Appraisal of “usefulness” of the papers Check in aims and Hypotheses, – If they agree with your need for information;s In methods check, – If the paper studies same population as yours; – If the study subject complies with your need – If sample size and study power are given; – If appropriate statistical methods were used;s In results check, – For ev. biases and flaws; – If the results are valid for your practice; – If the statistical significance has also any clinical meaning. EBM 45 7. 5. 2012
  46. 46. IMRADs Introduction (why the authors decided to do this research),s Methods (how they did it, and how they analysed their results),s Results (what they found), ands Discussion (what the results mean).7. 5. 2012 EBM 46
  47. 47. Paper quality criteria– introduction and methodss Is the purpose clear?s What is the measure of the study succes?s Is the methodology understandable?s Where are the patients from?s What is the selection of patients?s Methods of data collections What is the percentage of responses?s Is the number of observations sufficient?7. 5. 2012 EBM 47
  48. 48. Paper quality criteria– results and conclusionss Whether they used appropriate statistical methods?s Are the results shown appropriately or misleading?s Are there confidence intervals shown?s Are the conclusions based on the study results?s Are the authors aware of limitations and potential biases?s Recommendations for further study?7. 5. 2012 EBM 48
  49. 49. Methodss Random allocation of study participantss Researchers were blinded for the initial allocations The groups did not differ at the beginning of the studys Researchers were blinded for actual allocations Was analysis performed on all included participants?7. 5. 2012 EBM 49
  50. 50. Appraisal of recomendations in the guidelines (GRADE, BMJ 2004, 328: 1490-8)s A: The opinion supports more quality studies - there is no major change in knowledge expected.s B: Opinion supported by one or more major study weaker or incomplete study - we can expect changes in knowledge.s C: Opinion support some studies, but not always quality ones - future research is likely to result in significant changes in knowledge.s D: No reliable conclusion is possible. 7. 5. 2012 EBM 50
  51. 51. Appraisal of meta-analysis (Cochrane)s Described protocol of meta-analysiss Description systematic literature searchs Criteria for inclusion or exclusion of studies, research, and that all the reasons why they were excludeds The homogeneity of the results shown by testss Appropriate statistical analysis were useds In the case of statistically significant differences the possibility of biases due to variability of studies explaineds Conclusions shown with regard to treatment decisions EBM 7. 5. 2012 51
  52. 52. Conclusionss Knowledge becomes quickly obsolete, or new replaces old dogmas.s Physicians must follow new findings.s Information is unlimited, our ability is limited.s Reliance on the eminence does not suit any more.s We urgently need to know how to find and use appropriate sources of new knowledge.7. 5. 2012 EBM 52
  53. 53. Thank you very much for yourattention!
  54. 54. Group work: Evaluate papers!7. 5. 2012 EBM 54