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Evidence-based Practice (EBP) The What, the Why and the How

Evidence-based Practice (EBP) The What, the Why and the How. J. Irlam, Prof J. Volmink Primary Health Care Directorate UCT Faculty of Health Sciences April 2005 Adapted from a presentation by the South African Cochrane Centre, MRC. Outline of lecture. Definition of EBP

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Evidence-based Practice (EBP) The What, the Why and the How

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  1. Evidence-based Practice (EBP)The What, the Why and the How J. Irlam, Prof J. Volmink Primary Health Care Directorate UCT Faculty of Health Sciences April 2005 Adapted from a presentation by the South African Cochrane Centre, MRC

  2. Outline of lecture • Definition of EBP • Four Lessons from History • Challenges of the Information Age • How can EBP help? • Concluding comments Intro to EBP 2005

  3. Evidence-based Practice is.. “..the conscientious, explicit and judicious use of the current best evidence in making health care decisions” Sackett DL, Richardson WS, Rosenberg W, Haynes RB. Evidence-based Medicine. 1997 Intro to EBP 2005

  4. Why do we need to learn this stuff? • To be able to identify, appraise and apply best evidence in making health care decisions • To be able to continually appraise and assimilate new scientific evidence so as to remain up-to-date with new developments in medical knowledge and practice (UCT MBChB Graduate profile: Core Competencies) Intro to EBP 2005

  5. The need for EBP “Perhaps the most important issue facing the health care service is not how it should be organised or financed, but whether the care it provides actually works.” Bandolier, 1997 Intro to EBP 2005

  6. Four Lessons from History.. Intro to EBP 2005

  7. Lesson 1 Distinguish between medical ritual and evidence-based practice e.g. Optimal number of antenatal visits Intro to EBP 2005

  8. Lesson 2 What’s good in theory MUST be tested by sound research e.g. DES hormone to prevent complications of pregnancy Intro to EBP 2005

  9. Lesson 3 Clinical experience is necessary but not sufficient for making good clinical decisions e.g. anti-arrhythmic drugs after heart attack Intro to EBP 2005

  10. Lesson 4 Focus on outcomes that are important to patients rather than on surrogate endpoints e.g. anti-arrhythmic drugs after heart attack Intro to EBP 2005

  11. Challenges of the Information Age.. Intro to EBP 2005

  12. The Information Explosion • Journals • over 30 000 biomedical journals • over 2 million articles per year • Textbooks • Grey literature • MEDLINE: over 14 million citations (Dec. 03) • Worldwide Web Intro to EBP 2005

  13. Intro to EBP 2005

  14. Recent health news • “Too much sleep makes you fat, say scientists” • “Some flab is fab, says new obesity study” • “Daycare may ward off leukaemia” Intro to EBP 2005

  15. Who do you believe? Intro to EBP 2005

  16. How can Evidence-Based Practice help? Intro to EBP 2005

  17. Steps towards Evidence-Based PracticeThe Five A’s • Ask the right question • Access the relevant evidence • Appraise the evidence • valid? clinically important? • Apply the evidence to patient care • feasible? acceptable? • Assess clinical practice regularly Intro to EBP 2005

  18. 1. Ask the right question DEFINE: Population Intervention/ Exposure Comparison group Outcomes Intro to EBP 2005

  19. Case scenario 1: to immunise or not to immunise? John is an infant. His parents seek your advice about the risk of severe adverse reactions to the pertussis vaccine. Intro to EBP 2005

  20. Case scenario 1What is the clinical question? • POPULATION: Infants • INTERVENTION: Pertussis vaccine • COMPARISON: Non-pertussis/ placebo vaccine • OUTCOME: Severe adverse reactions • Does the pertussis vaccine increase the risk of severe adverse reactions in infants compared to no or other vaccines? Intro to EBP 2005

  21. Case scenario 2Vasectomy and testicular cancer George has come to discuss the possibility of getting a vasectomy. He says he has heard something about vasectomy causing an increase in testicular cancer later in life. You know that the risk of this is low but want to give him a more precise answer. Intro to EBP 2005

  22. Case scenario 2What is the clinical question? Population = adult males Intervention = vasectomy Comparison = no vasectomy Outcome= testicular cancer • Does vasectomy increase the risk of testicular cancer in adult males compared to no vasectomy? Intro to EBP 2005

  23. 2. Access the evidence • Cochrane Library • Database of Systematic Reviews (CDSR) • Database of Abstracts of Reviews of Effects (DARE) • Central Register of Controlled Trials (CENTRAL)   • MEDLINE (PubMed Clinical Queries) • Systematic Reviews • Clinical Queries using Research Methodology Filters Intro to EBP 2005

  24. Intro to EBP 2005

  25. 3. Appraise the evidence - 1 Best • Systematic reviews • Randomised controlled trials (RCT) • Observational studies (cohort, case-control, cross-sectional) • “Expert” opinions, based on clinical evidence, descriptive studies, or reports of expert committees • Anecdote: ”Someone once told me…” Worst Intro to EBP 2005

  26. 3. Appraise the evidence - 2 Is the study design appropriate to the question? • What are the risk factors for this condition? • Cohort Study or Case-Control Study • Is the diagnostic / screening test valid? • Cross sectional (validation) studies • What is the best intervention? • Randomised controlled trials (RCTs) • What is the prognosis? • Cohort Study or Case-Control Study Intro to EBP 2005

  27. 3. Appraise the evidence - 3 I. Are the results of the study valid? • Could the results be due to bias? • Could the results be due to confounding? • Could the results be due to chance? Intro to EBP 2005

  28. Critical appraisal and causal inference Could it be due to confounding? Could it be due to selection or measurementbias? NO NO Observed association Could it be the result of chance? Apply guidelines and make judgment Could it be causal? NO NO Intro to EBP 2005

  29. 3. Appraise the evidence - 4 II. What are the results? Are they large enough .. (As measured by the relative risk, absolute risk, or odds ratio) and precise enough .. (As measured by the confidence interval or p-value) and clinically relevant? (As measured by the Number Needed to Treat (NNT) Intro to EBP 2005

  30. Which screening programme would you fund? • Programme A reduced the risk of breast cancer deaths by 34% • Programme B produced an absolute reduction in breast cancer deaths of 0.06% • Programme C meant that 1592 women needed to be screened to prevent 1 death from breast cancer • Programme D increased the proportion of patients surviving breast cancer from 99.82% to 99.88% Intro to EBP 2005

  31. 4. Apply the evidence III. How relevant are the results to my patient? • Were the study participants sufficiently different from my patient that the results don’t apply? • Is the treatment feasible in my setting?  • What are the potential benefits and harms to my patient from the intervention? • Are my patient’s values and preferences satisfied by the intervention and its consequences? Intro to EBP 2005

  32. 5. Assess your clinical practice regularly • How good am I in asking answerable clinical questions? • How successful am I in getting answers to these questions? • Do I critically appraise the evidence? • How well am I applying the evidence in my practice? Intro to EBP 2005

  33. In Conclusion.. Intro to EBP 2005

  34. EBP is a systematic approach to using evidence for better patient care • Asking the right questions • Accessing the relevant evidence • Appraising the evidence • valid? clinically important? • Applying evidence to patient care • feasible? acceptable? • Assessing clinical practice regularly Intro to EBP 2005

  35. EBP is about integrating evidence with clinical expertise “The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research.” BMJ 1996;312:71-72 Intro to EBP 2005

  36. The potential of EBP • Improves continuity and uniformity of care • Provides a structure for effective teamwork • Provides a common structure for problem-solving and communication • Promotes better use of resources Rosenberg, Donald. BMJ 1995; 310:17-25 Intro to EBP 2005

  37. The difficulties of EBP “The notion that right-minded people will naturally make decisions on the basis of the best available scientific evidence is a misleading and dangerous idea” Erve Chambers, 1985 “The presumption is made that the practice of medicine was previously based on a direct communication with God or by tossing a coin.” Fowler, Lancet 1995;346:823 Intro to EBP 2005

  38. For the best quality health care, use of the best available evidence is essential Intro to EBP 2005

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