JAMA Facial Plastic Surgery : Evidence-Based Medicine and Level of Evidence Primer

1. JAMA Facial Plastic Surgery:Evidence-Based Medicine and Level of Evidence Primer John S. Rhee, MD, MPH Wayne F. Larrabee, Jr, MD

2. 1 What Is Evidence-Based Medicine? Evidence-Based Medicine and Level of Evidence Primer

3. What Is Evidence-Based Medicine? • “The conscientious, explicit and judicious use of the current best evidence in making decisions about the care of individual patients.” – Sackett et al1 • Integration of 3 critical elements • Best research evidence • Clinical expertise • Patient values • 1Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. BMJ. 1996;312(7023):71-72. Evidence-Based Medicine and Level of Evidence Primer

4. What Is Evidence-Based Medicine? Evidence-Based Medicine and Level of Evidence Primer

5. What Evidence-Based Medicine Is Not • EBM is not “old hat” • “Everyone is doing it already” • EBM is not impossible to practice • EBM is not “cookbook” medicine • EBM is not cost-cutting medicine • EBM is not restricted to randomized controlled trials (RCTs) and meta-analyses Evidence-Based Medicine and Level of Evidence Primer

6. Case Example • Dr Nash has been in practice for 10 years. He sees a 60-year-old woman in his office who would be a good candidate for a face-lift. Patient asks about “new medicine X” that may decrease postsurgical bruising. He is unsure if he should recommend the use of this medication. Evidence-Based Medicine and Level of Evidence Primer

7. The MEDLINE Search • MeSH, Google? – rhytidectomy, “new medicine X,” aging face, ??? • Limiting the search • Randomized clinical trial (RCT)? Meta-analyses? Cochrane review? • Level of evidence • Best level is 4? • Best level is 2? Evidence-Based Medicine and Level of Evidence Primer

8. Level of Evidence Table • Adapted from Oxford Centre for Evidence Based Medicine. http://www.cebm.net/index.aspx?o=1001. Evidence-Based Medicine and Level of Evidence Primer

9. Level of evidence plays a role in just 1 circle (current best evidence) in the EBM picture Evidence-Based Medicine and Level of Evidence Primer

10. How to Critique an Original Study: Going Beyond Level of Evidence • Are the results valid? • Patient dropout rate • Length of follow-up • Patient cohort makeup • What are the results? • How large was the treatment effect? • How precise was the estimate of the effect? • How was the effect measured? • Are the results applicable to my patients? • Study patients similar to my patients? • Outcome measures clinically relevant? • Are my surgical skills and techniques similar to those of the study surgeons? Evidence-Based Medicine and Level of Evidence Primer

11. Incorporate All 3 Elements of EBM Evidence-Based Medicine and Level of Evidence Primer

12. Case Example (Reprise) • Dr Nash integrates the 3 elements of evidence-based medicine to decide what to do for this patient • Literature review and best evidence level • Best available evidence is 2, no RCTs • Predominantly level 4 evidence supporting efficacy of this medication • Clinical expertise • Comfortable with own surgical procedure and past outcomes without “new medication X” • Surgical cohort in study was predominantly male with different surgical technique, so results may not be applicable for his patient • Patient values • Patient is aware of surgeon experience with procedure and made aware of current level of evidence and accepts recommendations of surgeon not to use “new medication X” Evidence-Based Medicine and Level of Evidence Primer

13. 2 Facing Levels of Evidence The JAMA Facial Plastic Surgery Initiative Evidence-Based Medicine and Level of Evidence Primer

14. Levels of Evidence Designation • Only applicable to clinical, therapeutic (disease treatment) studies • Examples include any treatment or interventions in which outcomes are provided • Nonratable articles include (but are not limited to) narrative reviews, editorials, videos, and studies that are basic science, non–human-based, diagnostic, and cadaver/anatomy and survey/questionnaire based Evidence-Based Medicine and Level of Evidence Primer

15. Building Blocks of Evidence-Based Practice Slide 15 Evidence-Based Medicine and Level of Evidence Primer Evidence-Based Medicine and Level of Evidence Primer January 2, 2020 •

16. Level of Evidence Table • Adapted from Oxford Centre for Evidence Based Medicine. http://www.cebm.net/index.aspx?o=1001. Evidence-Based Medicine and Level of Evidence Primer

17. Study Designs Evidence-Based Medicine and Level of Evidence Primer

18. Descriptive Studies • Observational, nonanalytic • Describe patterns of “distribution of disease” • Person, place, time • Quick, easy, inexpensive • Help in “formulation of hypotheses” Evidence-Based Medicine and Level of Evidence Primer

19. Case Report – Level of Evidence: 5 • Observational, descriptive • Detailed report of an unusual observed characteristic of a single patient • Advantages • Inexpensive • May lead to formulation of hypothesis • Disadvantages • Based on experience of 1 patient Evidence-Based Medicine and Level of Evidence Primer

20. Case Series – Level of Evidence: 4 • Observational, descriptive • Characteristics observed in group of patients • Advantages • Inexpensive • Useful in formulation of hypothesis • Disadvantages • No control group • Bias related to subject or characteristic selection Evidence-Based Medicine and Level of Evidence Primer

21. Cross-Sectional Studies – Level of Evidence: 4 • Observational, descriptive • Data on individual patients at 1 point in time • Exposure and disease measured simultaneously • Prevalence of disease and exposure can be calculated • Useful for formulation of hypothesis about presence of association between exposure and disease Evidence-Based Medicine and Level of Evidence Primer

22. Cross-Sectional Studies – Level of Evidence: 4 • Advantages • Inexpensive • Best design for studying the status quo of disease or condition • Disadvantages • Provide only a “snapshot in time” • “The chicken or the egg” dilemma • Difficult to choose control or comparison group Evidence-Based Medicine and Level of Evidence Primer

23. Study Designs Evidence-Based Medicine and Level of Evidence Primer

24. Analytic Studies:Observational or Experimental • Provide information about determinants of disease by testing hypotheses • Observational analytic studies • “Investigator simply observes” • Experimental analytic studies • “Investigator allocates exposure” Evidence-Based Medicine and Level of Evidence Primer

25. Case-Control Studies – Level of Evidence: 3 • Observational, analytic • Cases matched with controls • Cases = those with disease/outcome of interest • Control = comparative group without disease • Past “exposure” is determined • Proportions with the “exposure” within each group are compared Evidence-Based Medicine and Level of Evidence Primer

26. Case-Control Studies – Level of Evidence: 3 • Advantages • Quick and least expensive of analytic designs • Efficient for rare diseases with long latent periods • Disadvantages • Control group selection difficult • Disease incidence rates and relative risks cannot be calculated • Temporal relationship between exposure and disease is sometimes difficult to establish • Prone to selection and recall bias Evidence-Based Medicine and Level of Evidence Primer

27. Prospective Cohort Studies – Level of Evidence: 2 • Observational, analytic • Participants are free of disease/outcome of interest at onset of study • Participants selected on exposure/risk factor under study • Exposed group (treatment group) vs unexposed group • Participants followed over period of time to assess occurrence of disease or outcome • Formulation of incidence rates and relative risk Evidence-Based Medicine and Level of Evidence Primer

28. Prospective Cohort Studies – Level of Evidence: 2 • Advantages • Establishment of temporal relationship between exposure (treatment) and disease • Assessment of multiple effects of a single exposure (treatment) • Calculation of incidence rates and relative risk • Selection bias can be controlled or minimized • Disadvantages • Very time-consuming and expensive • Inefficient for rare diseases • Dropout rate can affect validity of results • An association but not necessarily causation between exposure (treatment) and disease can be made Evidence-Based Medicine and Level of Evidence Primer

29. Study Designs Evidence-Based Medicine and Level of Evidence Primer

30. Therapeutic Experimental Studies • Randomized or nonrandomized • Analytic studies • Commonly called clinical trials • Exposure/intervention is controlled or allocated by investigator • Experimental group vs control group • Participants screened for eligibility Evidence-Based Medicine and Level of Evidence Primer

31. Nonrandomized Clinical Trials – Level of Evidence: 2 • Comparison group is historical • Historical controls • Can lead to bias in analysis • Weaker study design due to bias in patient assignment Evidence-Based Medicine and Level of Evidence Primer

32. Randomized Clinical Trials – Level of Evidence: 1 • “Gold standard” in study designs • Randomized assignment to either experimental or control group • Removes potential selection bias • Potential for bias is prevented by blinding the participant to the intervention • Double-blinded = when both investigator and participant are blinded to the intervention Evidence-Based Medicine and Level of Evidence Primer

33. Randomized Clinical Trials – Level of Evidence: 1 • Advantages • Provide strongest evidence for determining causation • Least number of problems or biases • Best design to assess efficacy of a treatment or procedure • Disadvantages • Very expensive and time-consuming • Inefficient if effect of treatment is small • Criteria for measuring outcome may be controversial • Ethical issues Evidence-Based Medicine and Level of Evidence Primer

34. Meta-analysis Studies – Level of Evidence: 1 • Results from published studies combined to provide overall conclusion • Ideally comprised of RCTs only • Smaller sample–sized studies that do not achieve statistical significance are combined • Studies need to be similar with respect to disease and exposure/intervention Evidence-Based Medicine and Level of Evidence Primer

35. Meta-analysis Studies – Level of Evidence: 1 • Advantages • Provide a reliable estimate of most likely effect of an exposure/intervention • Useful for planning future trial with adequate power • Disadvantages • Carry risk of several biases • Meta-analysis of observational studies especially suspect • Too much bias and too many confounding variables Evidence-Based Medicine and Level of Evidence Primer

36. Systematic Reviews – Level of Evidence: Variable • A thorough and systematic review of the literature targeted by a specific research question • Methods and results should be reproducible and transparent to all • May assign levels of evidence to existing studies • Identify knowledge gaps and point to needed areas of investigation • Dependent on level of evidence of primary literature Evidence-Based Medicine and Level of Evidence Primer

37. Meta-analysis ≠ Systematic Review Systematic Review Meta-analysis Evidence-Based Medicine and Level of Evidence Primer

38. JAMA Facial Plastic Surgery:Evidence-Based Medicine and Level of Evidence Primer John S. Rhee, MD, MPH Wayne F. Larrabee, Jr, MD