Levels of evidence, systematic review and guidelines

Levels of evidence, systematic review, guidelines

1. Levels of evidence
Systematic reviews and
Guidelines



Aboubakr Elnashar
Benha University Hospital, Egypt
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2. Levels of evidence
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3. EBM
requires the integration of the:
•Current best research Evidence with
•Our clinical Expertise and
•Patient’s values, preferences and
circumstances.
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4. Three (Es) - EBM Components
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5. Level of evidence
I
1 Systematic reviews.
2 One or more large double-blind RCT.
II
1 One or more well-conducted cohort studies.
2 One or more well-conducted case-control studies.
3 uncontrolled experiment.
III Expert opinion.
IV Personal experience
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6. 6

7. 7

8. 8

9. 9

10. 10

11. 11

12. RCT:
A group of patients is randomized into
study group & control group.
These groups are followed up for the
variables/outcomes of interest.
If the sample size is large enough,
this study design avoids problems of
bias and confounding variables
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13. Randomized Controlled study
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14. Searching for the Best Evidence
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15. Systematic Review
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16. Define
A review of a clearly formulated question that
uses systematic & explicit methods to
1. identify, select and critically appraise relevant
research
2. collect & analyse data from the studies that are
included in the review
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17. Appraised Topic
Topic:
A subject of
discussion or
conversation
Appraise:
To evaluate, &
estimate the
quality, amount
of validity, results
and applicability

Critical:
careful, exact evaluation
and judgment
Critically
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18. Appraise The Evidence (RVRA)
1. Relevance:
It focuses on medical problems common to our
practice. patient-oriented evidence
2. Validity:
Correctness (likely to be true)
3. Results:
Clinically important
4. Applicability:
Applicable in and useful for my patients

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19. Systematic Review and Meta-analysis
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20. Systematic
review
Meta-analysis
Literature
review
Meta-Analysis
The use of statistical techniques in a systematic review
to integrate the results of included studies.

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21. QUESTION Broad Focused

SOURCES/ Usually unspecified Comprehensive;
SEARCH Possibly biased explicit


SELECTION Unspecified; biased? Criterion-based;
uniformly applied

APPRAISAL Variable Rigorous

SYNTHESIS Usually qualitative Quantitative

INFERENCE Sometimes Evidence-based
evidence-based
NARRATIVE SYSTEMATIC
Cook, D. J. et. al. Ann Intern Med 1997;126:376-380 21

22. Why on the Top?
•Meticulous methodology
•Peer reviewed
•Relatively large sample size
•Ensures the highest quality evidence

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23. Why do we need it?
•Too much trials
25000 biomedical journals in print
8000 articles published per day
•All studies not equally well designed or interpreted
So, we need a study of studies
•To summarize evidence from studies that address a
specific clinical question.
•To explain differences among studies on the same
question
•To limit bias (rigorous methodology & clear reporting)

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24. Model of a Cochrane
systematic review
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25. Prof. Archie Cochrane (1909–1988)
Scottish doctor
His book Effectiveness and Efficiency:
Random Reflections on Health Services.

Advocated: use of RCT to make medicine
more effective and efficient:
Cochrane Library database of systematic
reviews
UK Cochrane Centre in Oxford
international Cochrane Collaboration.

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26. The Cochrane Collaboration
•International collaboration
•Prepares, maintains, and disseminates
systematic reviews
•Diverse internal structure (Review Groups,
Centres, Fields, Methods Groups, the
Consumer Network)
Cochrane Library
•The current resource with the highest methodological
rigor
•$235/year or abstracts only
•www.cochrane.org

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27. The logo
represents meta-analysis of 7 trials of IM
corticosteroids given to mothers for
foetal maturation in preterm infants
[Chalmers et al].

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28. Abstract
Background
Objectives
Criteria for considering studies for this review
Types of participants
Types of intervention
Types of outcome measures
Types of studies
Search strategy for identification of studies
Methods of the review
Description of the studies
Methodological qualities of included studies
Results
Discussion
Conclusions
Implications for practice
Implications for research
Internal sources of support to the review
External sources of support to the review
Potential conflict of interest
Acknowledgements
Contribution of Reviewer(s)
Synopsis
Characteristics of included studies
Table 01 results
References to studies included in this review
Additional references
Typical Systematic Review “Skeleton”
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29. Steps to do a systematic review
•Well-Formulated Question
•Efficient Search Strategies
•Review Abstracts to Determine Eligibility
•Apply Strict Inclusion/Exclusion Criteria
•Extract the Data
•Perform the Required Analyses (Meta-analysis)
•Interpret the Results
•Determine Implications for Health Care Policy and
Practice
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30. Methodology
•At least 3 reviewers
•Detailed description of :
Trial design characteristics
Why included / excluded
Quality of included studies in details
Source of articles
•Electronic databases
•Bibliography of selected articles
•Hand searching Journals
•“Gray” Literature
•Key Informants
•Web Searching

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31. 31

32. What Are CPG?
•Systematically developed statements to assist
practitioner decisions about appropriate
healthcare for specific clinical circumstances
E.g.: Guidelines For C.S.

Field MJ, Lohr KN, 1992 32

33. What they are not…
Clinical protocols:
•Rigid statements allowing little or no flexibility or
variation.
•Set out a precise sequence of activities to be
adhered to in the management of a specific
clinical condition.
–Guidelines for management of preeclampsia
–Protocol of MgSO4 for severe preeclampsia

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34. The Purpose of CPG
To identify effective:
diagnostic
screening
treatment strategies
Thus improve:
the quality of healthcare
the consumer outcomes.
Decrease variation between practices

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35. Types of Guidelines
Consensus Based Guideline:
The most common form
agreement among a group of experts.

Evidence Based Guideline:
Developed after the systematic retrieval
Appraisal of information from the literature
Strength of the evidence.

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36. Principles of good guidelines
•Using the best available evidence
•Making recommendations based on evidence
•A multidisciplinary approach which includes
consumers
•Flexibility and adaptability (age, racial, rural,
urban)
•Evaluation and Revision (update 3 -5 years)



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37. Different Levels of Guideline Use
•Adopt the guideline (same language/format)
•Keep the text but change the format
•Translate the guideline
•Adapt the guideline (which may include an
update of literature and/or addition of questions)
•Use the guideline as literature (review of
evidence)
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38. • Guidelines are usually developed by
• Government agencies
• Institutions
• Professional societies
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39. Guideline Development
1.Guideline topic selection
2.Guideline development team formation
3.Purpose & scope of guidelines
4.Identification of key questions
5.Systematic literature review
6.Grading recommendation
7.Consultation and peer reviewing
8.Publication and dissemination
9.Implementation of guidelines
10. Auditing, reviewing and updating
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40. Developing Guidelines
•Large investment of resources
•Long time to develop
•Training to bring in specific skills,
including
–expertise in guideline development
–skills for searching and evaluating the
literature
–leading small group process
–information management
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41. It doesn’t have to reinvent the wheel!
It can use ready synthesized EB-guidelines
after modifying them to suite our local needs,
health problems, and economic situations.

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42. http://www.nice.org.uk
National Institute for Clinical Excellence (NICE)
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43. http://www.sign.ac.uk
The Scottish Intercollegiate Guidelines Network (SIGN)
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44. http://www.guideline.gov
National Guidelines Clearinghouse
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45. http://www.nzgg.org.nz
New Zealand Guidelines Group
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46. http://www.library.nhs.uk/guidelinesfinder
UK NHS National Library of Guidelines
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47. Thank You

Aboubakr Elnashar


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