Introduction to EBM

1. Introduction to EBM Rodney Smith, MD St. Joseph Mercy Hospital University of Michigan

2. Objectives • What is EBM and Why do it? • Describe the EBM Process and its components • Patient Problem • Clinical question • Search for Evidence • Critical Appraisal of the Evidence • Apply the Results • The EBM Lecture

3. Introduction • What is EBM? • "...the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients." • Integrated with clinical expertise • expertise in performing the history and physical examination • knowledge of the patient, the family, and the community which creates a context for therapeutic decision-making • a relationship with the patient informed by his or her beliefs and values • practical knowledge of the availability of resources in the community

4. Introduction

5. Introduction • "Without clinical expertise, practice risks becoming tyrannized by external evidence, for even excellent external evidence may be inapplicable to or inappropriate for an individual patient.  Without current best external evidence, practice risks becoming rapidly out of date, to the detriment of patients."

6. Introduction • Why do EBM • It is required by RRC/Residency • Provide high quality care to patients • Utilize high quality evidence in patient care • Overcome limitations of current practice

7. Introduction • Examples • Prevention of SIDS…”Back to Sleep” • Patching corneal abrasion • Arryhthmia suppression • Ecainide/flecainide • Arrhythmia suppression • RCT increased mortality • Disease specific vs. patient specific outcomes

8. Introduction • The failure of common sense • I shake a tree, an apple falls out, now I can eat • I give antibiotics for sinusitis, the patient gets better, I’m doing a good job as a doctor • I just saw a patient with tumor lysis syndrome, I will start looking for it more and maybe I’ll find it more

9. Introduction • Variation in practice • Rate of prostatectomy for prostate CA

10. Introduction

11. Introduction • Source of Medical Information • Colleagues • Conferences • Drug Reps • Textbooks • Journals • Internet/Patients

12. Introduction

13. The Clinical Question • Physician recall • 1 question per 4 patients • Direct observation Covell DG, et al. Ann Intern Med 1985;103:596-9. • 2 questions per 3 patients • 15 questions per shift • Information sources • Textbooks • PDR • Human sources • 2/3 of questions go unanswered

14. The Clinical Question • Unrecognized • Recognized • Pursued • Satisfied • Implemented

15. The Clinical Question

16. The Question • Background • Anatomy and Physiology • Pathophysiology • Pharmacology and Toxicology • Differential diagnosis • Diagnostic testing • Treatment • Textbooks, reviews, lectures, experts

17. The Clinical Question • Foreground • Detailed information • Patient focus • Evidence-based process

18. The Clinical Question • Patient or problem • Intervention • Comparison • Outcome

19. The Question • Patient or Problem • Starts from the patient encounter • Unrecognized vs. Recognized • Intervention • Be specific • Compared to what • Outcome • Disease-center vs. Patient-centered

20. Example • 68 yo WF, Hx CHF, S/P CABG, HTN, COPD • Meds: Digoxin, Lasix, Isosorbide, Albuterol • Mild increase in DOE past 4 days • Acutely SOB 1hr PTA • 188/104 122 30 98.8 90% Non-rebreather • Crackles bases, Wheezes scattered • JVD, S3 gallop • Pretibial edema 2+

21. Example • BNP now available at St. Joe’s • Should I order a BNP on this patient?

22. The Clinical Question • Patient or problem • Intervention • Comparison • Outcome

23. The Question • ED patients with acute dyspnea • BNP • Standard evaluation • Diagnosis of CHF

24. Finding the Evidence • Textbooks – NOT! • Always out of date • Recommendations often not referenced

25. Finding the Evidence • Textbooks • Clinical Evidence • Published twice yearly • Full version 1900 pages • Concise version 400 pages • CD ROM • Online Access • Cost $110 • www.clinicalevidence.com

26. Finding the Evidence • Textbooks • Scientific American Medicine • Online subscription $199 • www.samed.com • Harrison’s Textbook of Internal Medicine • Online subscription $99 • www.harrisonsonline.com

27. Finding the Evidence • EBM Textbook • Evidence-Based On-Call • Database of critically appraised topics (CATs) • Bullet points with links to in-depth CAT • www.eboncall.co.uk/content.jsp.htm

28. Finding the Evidence • EBM Journals • ACP Journal Club • 6 Issues per year • Online access • $78/yr Individual • $55/yr Residents

29. Finding the Evidence • EBM Journals • Bandolier • Summaries of secondary reviews • Free online access • www.jr2.ox.ac.uk/bandolier

30. Finding the Evidence • EBM Journals • Evidence Based Medicine • Now combined with ACP Journal Club • Articles from 1999 and prior available free online • www.acponline.org/journals/ebm/ebmmenu.htm

31. Finding the Evidence • EBM Databases • Evidence Based Medicine Reviews (EBMR) • Commercially available thru OVID • Searches a variety of databases • Cochrane Database of Systematic Reviews • ACP Journal Club • Medline • Links databases together

32. Finding the Evidence • EBM Databases • Cochrane Library • The Cochrane Database of Systematic Reviews • The Cochrane Controlled Trials Register

33. Finding the Evidence • EBM Databases • SUMSearch • Merck Manual. • MEDLINE for review articles and editorials from high quality, general journals that have full texts available. • National Guideline Clearinghouse from the Agency for Health Care Policy and Research (AHCPR) • Database of Abstract of Reviews of Effectiveness (DARE) • MEDLINE for original research • sumsearch.uthscsa.edu

35. Finding the Evidence • EBM Databases • MEDLINE • Free online access thru PubMed • www.ncbi.nlm.nih.gov/entrez/ • Search by MESH terms or free text • EBM Filters

36. Finding the Evidence

37. Finding the Evidence

38. Finding the Evidence

39. Finding the Evidence

40. Finding the Evidence

41. Finding the Evidence

42. Finding the Evidence • Filters for Medline Search • Treatment • Randomized controlled trial • Blind or Double Blind • Diagnosis • Sensitivity and Specificity

43. Critical Appraisal • Is the evidence valid? • Is evidence important? • Does the evidence apply to our patient?

44. Critical Appraisal • Users’ Guides to the Medical Literature • Book by Guyatt and Rennie • Available thru AMA/ Amazon.com $35/$60 • CD-ROM version • www.usersguides.org • www.cche.net/usersguides/main.asp/

45. Critical Appraisal • Diagnosis • Is the evidence valid? • Was there an independent, blinded comparison with a gold standard? • Was the test evaluated in an appropriate spectrum of patients? • Was the reference standard applied regardless of the test result? • Was the test validated in a second, independent group of patients?

46. Critical Appraisal • Diagnosis • Is this valid test important? • Distinguish between patients with and those without the disease • Two by two tables • Sensitivity and Specificity • SnNOut • SpPIn • ROC curves • Likelihood Ratio

48. 2 X 2 Table • Sensitivity = 90% • Specificity = 90% • Pos Predictive Value = 90% • Neg Predictive Value = 90%

49. 2 X 2 Table • Sensitivity = 90% • Specificity = 90% • Pos Predictive Value = 8.3% (90/1090) • Neg Predictive Value = 99.9% (9000/9010) • Prevalence = 1%

50. 2 by 2 Table • 90% with disease have a positive test • 15% without disease have a positive test • Someone with a Pos test is 6X more likely to have the disease as not (90%/15%) • Likelihood Ratio + • Sens /(1- Spec)