EVIDENCE BASED MEDICINE

1. EVIDENCE BASED MEDICINE Using PICO to help define the problem

2. "Evidence-based medicine is the integration of best research evidence with clinical expertise and patient values." Sackett, D. L. (2000). Evidence-based medicine: How to practice and teach EBM(2nd ed.). Edinburgh; New York: Churchill Livingstone.

3. Why Is It So Hard to Be Up-to-date? • The database of the National Library of Medicine MEDLINE has 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

4. 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!

6. PATIENT value EBM PHYSICIAN INFORMATION

7. Information Mastery (Relevancy) • Articles • POEM: Patient-oriented evidence that Matters • mortality, morbidity, quality of life • DOE: Disease-oriented evidence • pathophysiology, pharmacology, etiology

8. DOE POEM Examples of Hypothetical DOE and POEM studies Drug A decreases overall mortality Drug A lowers cardiovascular mortality Drug A lowers cholesterol HRT increase cardiovascular mortality HRT do not decreases overall mortality!! HRT lowers cholesterol Fluoride increase osteoblastic activity Fluoride increase Fx!! Fluoride increase BMD Pathophysiologic reasoning

10. Steps EBP: • Assess the patient • Ask the question • Acquire the evidence • Appraise the evidence • Apply: talk with the patient EBM: Ask focused question Find the evidence Appraise the evidence Make a decision Evaluate performance

11. Five steps to Evidence-Based Care (EBC): • ASK = Develop your answerable clinical question • ACQUIRE = find the best evidence • APPRAISE = Critically evaluate the evidence for its validity and usefulness • APPLY = Use the results of the appraisal in your clinical practice • ASSESS = Evaluate your performance Sackett DL, Straus SE, et al. Evidence Based Medicine: How to Practice and Teach EBM 2nd Ed. Churchill Livingston: Edinburgh, 2000.

12. PICOANALYSIS • Before attempting to search for the evidence in the literature, construct a well-built or clearly structured question

13. The Well-Built Clinical Question:“PICO” Model • Patient/Population/Problem (among ______) • Intervention/Exposure (does______) • Comparison (versus _______) • Outcome (affect ________)

14. P=Patient/PopulationofInterest • Who are the patients of interest? • Is there a particular age group, gender or population? • What is the health concern?

15. I=InterventionorExposure • What medical event do you want to study the effect of? • What therapeutic, diagnostic, preventive or other health care interventions are you interested in knowing more about?

16. C=Comparisonof Interest • Compared to what?   • Is there a comparison to be evaluated against the intervention? • Only used if more than one intervention or if no intervention is a factor.

17. O=Outcomeof Interest • What is the effect of the intervention?  • What is the desired outcome to be evaluated? • How will the patient or population be affected, or not affected, by the intervention? Example from: DiCenso A, Guyatt G, Ciliska D. (2005). Evidence-Based Nursing: A Guide to Clinical Practice. St. Louis, MO: Mosby.

18. Categories of EBM Questions • After constructing the PICO analysis, determine the category of the question. • There are the four categories of EBM questions

19. 1) Therapy • Solves questions about which treatment to administer, and what might be the outcome of different treatment options.  • For most therapy questions one may want to look for the best evidence namely a randomized controlled study, and if the study can be a double blind, so much the better. 

20. 2) Diagnosis • Solves questions about degree to which a test is reliable and clinically useful, to decide whether the patient would benefit from it

21. 3) Etiology • Solves problems about the relationship between a disease and a possible cause

22. 4) Prognosis • Answers questions about a patient's future health, life span and quality of life in the event one chooses a particular treatment option.

23. Types of Research Studies

24. Randomized Controlled Trial (RCT) • Answers therapy, prevention questions • Randomization avoids selection bias

25. Cohort study • Answers prognosis, etiology, prevention questions • Researchers identify and compare two groups over a period of time. 

26. Case Control study • Answers prognosis, etiology, prevention questions

27. Case series & Case Reports  • Answers prognosis, etiology, prevention questions

28. Cross sectional study • Diagnosis

33. Example: • George wants to discuss the possibility of 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.

34. Question:‘In men, does having a vasectomy (compared to not having one) increase the risk of getting testicular cancer in the futhure.

35. Example: • Mabel is a 6-week-old baby at her routine follow-up. She was born prematurely at 35 weeks. You want to tell the parents about her chances of developing hearing problems.

36. Question:‘In infants born prematurely, compared to those born at full term, what is the subsequent lifetime prevalence of sensory deafness?'

37. Case The mother of a 5-year-old boy with a history of asthma has brought him to the emergency room with an acute exacerbation of his condition. She wants to know if this episode could be treated with a single injection of dexamethasone rather than a 5-day course of oral prednisolone, since she has had problems in the past getting him to take his medicine.

38. Let’s build the PICO P: ?? Children with acute asthma exacerbation I: ?? Single-dose injectable dexamethasone C: ?? Oral prednisolone x 5 days O: ?? Resolution of asthma symptoms

39. Clinical Question In a child with an acute asthma attack, does a single-dose injection of dexamethasone work as well as 5-day oral prednisolone in resolving asthmatic symptoms?

40. Example • Your patient is a 72-year-old woman with osteoarthritis of the knees and moderate hypertension. The daughter wants you to give her mother a prescription for one of the new COX-2 inhibitors. She has heard that they cause less GI bleeding.

41. Specific Question In a 72 year old woman with osteoarthritis of the knee, can COX-2 Inhibitor use decrease the risk of GI Bleeding compared with other NSAIDs?

42. Question Templates for Asking PICO QuestionsTherapyIn __________________, what is the effect of ____________________ on ______________________ compared with __________________?EtiologyAre ______________ who have _________________ at ________________ risk for/of ____________________ compared with _____________________ with/without ______________________?Diagnosis or Diagnostic TestAre (Is) _________________________ more accurate in diagnosing ________________ compared with ________________?PreventionFor _________________ does the use of _______________ reduce the future risk of ________________ compared with _________________?PrognosisDoes _______________ influence _________________ in patients who have __________________? Melnyk, B. M., & Fineout-Overholt, E. (2005). Evidence-based practice in nursing & healthcare : A guide to best practice. Philadelphia, PA: Lippincott Williams & Wilkins.