Evidence-Based Practice

1. Evidence-Based Practice 奇美醫學中心 林宏榮

2. What evidence-based medicine is: “Evidence-based medicine is the integration of best research evidence with clinical expertise and patient values” - Sackett, et al 2001

3. Clinical Expertise Best Evidence What evidence-based medicine is Patient Values

4. Rule 31 – Review the World Literature Fortnightly* *"Kill as Few Patients as Possible" - Oscar London 5,000? per day 1,400 per day 55 per day

5. The Airline industry Boeing 777 manuals 24 binders 10 feet shelf space Conversion to CD Reduced search by 60% The Health Industry Memorize “the manuals” Exams, audits, etc to check Managing Information

6. Systematic review of bed rest after medical procedures • 10 trials of bed rest after spinal puncture • no change in headache with bed rest • Increase in back pain • Protocols in UK neurology units - 80% still recommend bed rest after LPSerpell M, BMJ 1998;316:1709–10 • …evidence of harm available for 17 years preceding... Allen, Glasziou, Del Mar. Lancet, 1999

7. Getting Evidence in to PracticeHow do you “do” EBP? • What EBP do you do/help with? • What other EBP do you know of? • Compare with you neighbour Teaching Tip: Special background for activities.

8. Managing Information“Push” and “Pull”methods • “Push” - alerts us to new information • “Just in Case” learning • Use ONLY for important, new, valid research • “Pull” – access information when needed • “Just in Time” learning • Use whenever questions arise • EBM Steps: Question; search; appraise; apply

9. Bimonthly “just in case” journalValid, Relevant & (almost) No Effort! • 80 journals scanned • Is it valid? • Intervention: RCT • Prognosis: inception cohort • Etc • Is it relevant? • GPs & specialists ask:Will this change your practice? www.evidence-basedmedicine.com

10. “Just in Time” learning:Doctor’s information needs • Setting: 64 residentsat 2 New Haven hospitals • Method: Interviewed after 401 consultations • Questions • Asked 280 questions (2 per 3 patients) • Pursued an answer for 80 questions (29%) • Not pursued because • Lack of time • Forgot the question • Sources of answers • Textbooks (31%), articles (21%), consultants (17%) Green, Am J Med 2000

11. Doctor’s information needs • Most of our questions are NEVER answered • When answered, the information is likely to be neither the best nor up-to-date

12. Step #1Developing an answerable Clinical Question

13. Your Clinical Questions • Write down one recent patient problem • What was the critical question? • Did you answer it? If so, how?

14. Good questions • Important to your practice • Important to your patients • Specific • Answerable!

15. Good Questions • Which patients is this question about? • What is the main intervention? • Is there an alternative intervention? • What can I hope to accomplish?

16. “Hunting” questions - “PICO”: • “P” - patient or problem • “I” - intervention (e.g., diagnostic test, treatment, cause, prognostic factor) • “C” - comparison intervention (if necessary) • “O” - outcome

17. Examples of good questions • In patients with insulin-dependent diabetes mellitus • receiving current standard insulin therapy • will an intensive insulin regime • reduce the risk of developing microvascular complications

18. Examples of good questions • Among women in premature labour expected to deliver before thirty weeks of gestation • does an intensive corticosteroid regime • compared with the standard regime • reduce the risk of RDS in their babies?

19. Information “pull”Steps in EBM process • Formulate an answerable question • Track down the best evidence • Critically appraise the evidence • Integrate with clinical expertise and patient values

20. An example: “the first sign of hyperkalaemia is death” • An anxious laboratory technician phoned about a potassium of 7.3 mmol/l (Ref Range 3.5-5.0) found on a routine blood test of a 50 year old woman. • I arranged an urgent repeat of the electrolytes (to rule out a spurious elevation) and an ECG. • The latter was reassuringly normal, but left me asking: Does a normal ECG rule out a serious elevation of potassium?

21. 1. The question • Does a normal ECG rule out a serious elevation of potassium? • Population - In suspected hyperkalemia • Indicator - does a normal ECG • Comparator - • Outcome - rule out hyperkalemia?

22. 1. The question • Does a normal ECG rule out a serious elevation of potassium? • Population – hyperkal* • Indicator – ECG OR EKG • Comparator - • Outcome – hyperkal* • Underline keywords; think of synonyms

23. Step #2Efficiently track down the best evidence to answer clinical questions

24. Useful data sources MEDLINE Cochrane Library Clinical Evidence

25. searchable through Medline

26. searchable together

27. searchable individually

28. Using the tools • NLM (who make Medline) index thousands of medical journals • Each article is given keywords - • Major MESH terms • Minor MESH terms • The article title and abstract are also searchable - as Textwords

29. Using the tools • Search engines will sometimes match your entry to the nearest MESH term. • Sometimes they don’t • Experiment!

31. Filters • A filter is a sequence of Medline search instructions intended to locate specific types of study design • Filters exist for • clinical trials • studies of prognosis • studies of adverse effects • and many others….

32. Filters • Some search engines provide prepackaged filters • PubMed for example • Most don’t

34. PubMed via Google Diagnosis button “OR” synonyms * Means any letters

35. Diagnosis button

36. Sensitivity of 62% or 55%

37. Limit to EBM Reviews

38. Most Recent Update

39. Step #3 Appraising the evidence for validity

40. The “best” evidence depends on the type of question • What are the phenomena/problems? • Observation (e.g., qualitative research) • What is frequency of the problem? (FREQUENCY) • Random (or consecutive) sample • Does this person have the problem? (DIAGNOSIS) • Random (or consecutive) sample with Gold Standard • Who will get the problem? (PROGNOSIS) • Follow-up of inception cohort • How can we alleviate the problem? (INTERVENTION/THERAPY) • Randomised controlled trial

41. Treating hyperkalemia • She refused to go to hospital • Resonium A, but it is around $100 (RPBS but not PBS) which she could not afford. • My search had mentioned albuterol as a treatment.

43. Step #4Applying the results in clinical practice

44. Dave Sackett “Just in Time” learningThe EBM Alternative Approach • Shift focus to current patient problems(“just in time” education) • Relevant to YOUR practice • Memorable • Up to date • Learn to obtain best current answers

45. Advanced threshing • Read the abstract • Read the author list • Read references cited in several other papers • Consider levels of evidence • (as far as you can from abstracts)

46. Step #5 Explain Evidence

47. Internal validity • Is the study credible? • Was it done welll? • Was it done right? • Do you believe the authors? • Is the study good enough to consider making decisions based on its results?

48. Levels of evidence • Randomised controlled trials • Cohort studies • Case-control studies • Routine data hunting • Case series • Case reports • Allow for serendipity

49. Type and Strength of Evidence

50. Quality of evidence • Use Sackett’s guidelines for the various different types of study • Gain experience • Quality assessment is quite subjective, no matter how experienced you are • Allow for serendipity