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

1. Research Methodology and
Evidence Based Healthcare (EBHC481)
Principles of evidence-
Based medicine
Dr. Samer Rastam MD, PhD
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Lecture 17
Level 8
Year 4

2. Research Methodology and
Evidence Based Healthcare (EBHC481)
Objectives
1. Understand the importance of evidence-based medicine in healthcare.
2. Know how to formulate clinically relevant, answerable questions using the
Patient Intervention Comparison Outcome (PICO) framework.
3. Understand the importance of assessing the quality and validity of evidence
by critically appraising the literature.
4. Know that different study designs provide varying levels of evidence.
5. Know how to assess and implement new evidence in clinical practice.
6. Understand the importance of regularly evaluating the implementation of
new evidence-based practice.
7. Understand why clinical recommendations are regularly updated and list the
steps involved in creating new clinical practice guidelines.
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3. Research Methodology and
Evidence Based Healthcare (EBHC481)
What is EBM
• EBM is the integration of the: (3Es)
1. Evidence (research evidence): most updated and relevant
clinical research.
2. 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.
3. Expectations (patient’s values, preferences and
circumstances): the specific preferences, concerns, personal
values, and expectations of each patient.
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4. Research Methodology and
Evidence Based Healthcare (EBHC481)

5. Research Methodology and
Evidence Based Healthcare (EBHC481)
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
1. Daily need for valid information about diagnosis, prognosis, therapy and
prevention.
2. 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might be out-of-date (textbooks), potentially wrong (colleagues), or too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)
3. The disparity between our diagnostic skills/clinical judgment, which
increases with experience, and our up-to-date knowledge which declines
with time.
4. Our inability to afford more than a few minutes per patient for finding and
assimilating this evidence
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6. Research Methodology and
Evidence Based Healthcare (EBHC481)
Pathology papers (per year)
164,143
33,297
0
1
10
100
1,000
10,000
100,000
1,000,000
1800 1850 1900 1950 2000 2050
count
450 papers
per day

7. Research Methodology and
Evidence Based Healthcare (EBHC481)
Pathology of ulcerative colitis papers (per year)
581152
1
10
100
1000
1950 1960 1970 1980 1990 2000 2010 2020 2030
count

8. Research Methodology and
Evidence Based Healthcare (EBHC481)
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.
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9. Research Methodology and
Evidence Based Healthcare (EBHC481)
Hierarchy of evidence
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10. Research Methodology and
Evidence Based Healthcare (EBHC481)
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
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11. Research Methodology and
Evidence Based Healthcare (EBHC481)
• 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
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12. Research Methodology and
Evidence Based Healthcare (EBHC481)
WHO recommendations for Swine influenza
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13. Research Methodology and
Evidence Based Healthcare (EBHC481)
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
study design, totality of evidence (consistency), and the quality
of the studies.
• Power: The strength of the association = the size effect.
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14. Research Methodology and
Evidence Based Healthcare (EBHC481)
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)
1. Asking focused questions
2. Acquiring the evidence
3. Appraisal of evidence
4. Application of the best evidence in practice
5. Assessing and evaluating the performance
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15. Research Methodology and
Evidence Based Healthcare (EBHC481)
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”
1. P: The Patient (Population) and/or Problem being addressed.
2. I: The Intervention or exposure being considered.
3. C: The Comparison (control) intervention when relevant.
4. O: The clinical Outcomes of interest.
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16. Research Methodology and
Evidence Based Healthcare (EBHC481)
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.
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17. Research Methodology and
Evidence Based Healthcare (EBHC481)
• 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?
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18. Research Methodology and
Evidence Based Healthcare (EBHC481)
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.
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19. Research Methodology and
Evidence Based Healthcare (EBHC481)
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 ?
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20. Research Methodology and
Evidence Based Healthcare (EBHC481)
• 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:
• Systematic error: such as bias, confounding.
• Random error
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21. Research Methodology and
Evidence Based Healthcare (EBHC481)
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22. Research Methodology and
Evidence Based Healthcare (EBHC481)
4. Application of the best evidence in practice: Based on the
findings of the above, a clinical decision is to be made.
5. 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.
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23. Research Methodology and
Evidence Based Healthcare (EBHC481)
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)
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24. Research Methodology and
Evidence Based Healthcare (EBHC481)
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.
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25. Research Methodology and
Evidence Based Healthcare (EBHC481)
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:
1. Understanding of research process
2. Ethical consideration
3. Study design
4. Statistical analyses
5. Results interpretation.
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26. Research Methodology and
Evidence Based Healthcare (EBHC481)
References
1. Introduction to Clinical Research for Residents, Saudi
Commission for Health Specialties, 2014
2. Oxford Handbook of Clinical and Healthcare Research,
Sumantra Ray, Oxford, 2016
3. Crash Course Evidence-Based Medicine- Reading and Writing
Medical Papers, Amit Kaura (201)
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