L17 rm (principles of evidence-based medicine)-samer

This was given as a part of the course of Research & Evidence-Based Medicine given to fourth-year medical students (2018)

1. Principles of evidence-Based medicine Dr. Samer Rastam MD, PhD 1 Lecture 17 Level 8 Year 4

2. Objectives Understand the importance of evidence-based medicine in healthcare. Know how to formulate clinically relevant, answerable questions using the Patient Intervention Comparison Outcome (PICO) framework. Understand the importance of assessing the quality and validity of evidence by critically appraising the literature. Know that different study designs provide varying levels of evidence. Know how to assess and implement new evidence in clinical practice. Understand the importance of regularly evaluating the implementation of new evidence-based practice. Understand why clinical recommendations are regularly updated and list the steps involved in creating new clinical practice guidelines. 2

3. What is EBM EBM is the integration of the: (3Es) Evidence (research evidence): most updated and relevant clinical research. Expertise (clinical expertise): the clinical skills and past experience to identify each patient's unique health state and diagnosis and the specific risks and benefits of potential interventions. Expectations (patient’s values, preferences and circumstances): the specific preferences, concerns, personal values, and expectations of each patient. 3

4. The need for the evidence-based decision: In the past, physicians relied on their own experience or that of other health care workers to take decisions . Currently , this approach is inadequate and poor Daily need for valid information about diagnosis, prognosis, therapy and prevention. The inadequacy of traditional sources for this information because they might be out-of-date (textbooks), potentially wrong (colleagues), or too overwhelming in their volume (medical journals) The disparity between our diagnostic skills/clinical judgment , which increases with experience, and our up-to-date knowledge which declines with time. Our inability to afford more than a few minutes per patient for finding and assimilating this evidence 5

5. Pathology papers (per year)

6. Pathology of ulcerative colitis papers (per year)

7. EBM principles EBM involves two fundamental principles: Evidence alone is never the sole basis for decisions : Benefits and risks Costs Alternative strategies Patients values EBM has a hierarchy of strength of evidence for decisions : The hierarchy of evidence is a spectrum of potential sources beginning with those most likely to provide the evidence to those with the least likely . 8

8. Hierarchy of evidence 9

9. Hierarchy of evidence Hierarchy Meta-analysis = highest quality Randomized trial = high quality Quasi-randomized = moderate quality Observational study = low quality Any other evidence = very low quality 10

10. Decrease grade(s) if: Serious limitation to study quality . Important inconsistency Imprecise or sparse data High probability of reporting bias Increase grade if: Strong evidence of association based on consistent evidence from two or more observational studies. Evidence of a dose response gradient All plausible confounders would have reduced the effect 11

11. WHO recommendations for Swine influenza 12

12. Evidence Evidence is information that we use in deciding whether to believe a statement or proposition . Evidence have two major attributes : Validity (quality ): Closeness to the truth. Validity is based on s tudy design , totality of evidence ( consistency ), and the quality of the studies. Power: The strength of the association = the size effect. 13

13. EBM steps Practicing EBM is primarily based on five well defined steps, which can be broadly categorized as the five A‟s (5 A‟s) Asking f ocused q uestions Acquiring the e vidence Appraisal of evidence Application of the best evidence in practice Assessing and evaluating the performance 14

14. 1- Asking Focused Questions The question should be directly relevant to the problem at hand and should be phrased to facilitate searching for a precise answer. To achieve these aims, the question must be divided into four components, which are called “ PICO ” P : The Patient (Population) and/or Problem being addressed. I : The Intervention or exposure being considered. C : The Comparison (control) intervention when relevant. O : The clinical Outcomes of interest. 15

15. Example John, 31 years old, was diagnosed with heart failure 3 years old and prescribed a beta blocker which dramatically improved his symptoms. John’s 5- year-old daughter, Sarah, has been recently diagnosed with chronic symptomatic congestive heart failure. John asks you, Sarah’s pediatrician, whether his daughter should also be prescribed a beta-blocker . 16

16. Patient : Children with congestive heart failure Intervention : beta-blocker Comparison : No beta-blocker Outcome : Improvement of congestive heart failure symptoms Question : Is there a role for beta-blockers in the management of heart failure in children? 17

17. 2- Acquiring the Evidence In this step we make a systematic retrieval of the best evidence available. Choosing the best resource to search is an important decision. Following is a list of some valuable resources for practicing EBM: Summaries of the primary evidence : ACP Journal Club, Clinical Evidence Databases : PubMed, Cochrane Library Electronic textbooks and libraries : AccessMedicine , ACPMedicine , Meta-Search Engines : SUMSearch , TRIP Answers . 18

18. 3- Appraisal of evidence It is the process of assessing and evaluating the evidence for its internal validity, its clinical relevance, and applicability. Appraisal of evidence depends on the following 4 pillars - RVRA : Relevance : It focuses on the relevance of the literature to the question asked. Validity : Are the results of the study valid ? Results : What are the overall results? How precise are they? Applicability : Are the results Applicable in and useful for my patients ? 19

19. Validity : the degree to which a study reaches a correct conclusions . Two main components: Internal : the study is valid for the population of patients who were actually studies. External : the study is valid for other patients (Generalizability). Two types of errors threat the validity of the study: S ystematic error : such as bias, confounding. Random error 20

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21. Application of the best evidence in practice: Based on the findings of the above, a clinical decision is to be made. Assessing and evaluating the performance: Evaluating our effectiveness and efficiency in executing steps 1 - 4 and seeking ways to improve them both for next time . 22

22. Domains of EBM From a clinical perspective , evidence-based medicine is relevant for five key domains: Intervention (treatment): Whether an intervention is better than existing interventions or no treatment at all ? Etiology (harm): Is the exposure a risk factor for developing a certain condition? Diagnosis : How good is the diagnostic test (history taking, physical examination, laboratory or pathological tests and imaging) in determining whether a patient has a particular condition? Prognosis : Are there factors related to the patient that predict a particular outcome (disease progression, survival time after diagnosis of the disease, etc .)? Cost-effectiveness : Are any interventions worth paying for ? (commissioners, policymakers) 23

23. Limitations of EBM Lack of good evidence for many clinical questions Results may not be relevant for all treatment situations Lag in time between when the research studies is conducted, when its results are published when these are properly applied. 24

24. Linking research to EBM Finally, to be able to practice medicine based on the best evidence, the health care practitioner has to be equipped with both clinical and research knowledge. More specifically, research knowledge includes: Understanding of research process Ethical consideration Study design Statistical analyses Results interpretation. 25

25. References Introduction to Clinical Research for Residents, Saudi Commission for Health Specialties, 2014 Oxford Handbook of Clinical and Healthcare Research, Sumantra Ray, Oxford, 2016 Crash Course Evidence-Based Medicine- Reading and Writing Medical Papers, Amit Kaura (201) 26