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Systematic Review and Meta-analysis
AHMED SAID NEGIDA
Part 1
Learning objectives
1. Why systematic reviews?
2. Systematic reviews vs. Literature review
3. Types of Systematic reviews
...
Steps of systematic review
Research
Question
Eligibility
criteria
Searching
literature
Screening
Quality
assessment
Presen...
Summarize the Literature
Less Bias: Transparent and reproducible
More power
Source for Evidence-Based practice
Why
systema...
No, because about 32% of a set of
studies with at least 1,000 citations
were either contradicted by or
reported stronger e...
Yes. For example: A systematic review about
sudden infant death syndrome and sleeping
position could have saved 60,000 inf...
Systematic reviews are rapidly replacing
traditional narrative reviews as a means to
summarize and appraise literature.
Systematic review vs. Literature review
Systematic review Literature review
EVIDENCE High evidence Low evidence
METHOD Sys...
Meta-analysis
Quantitative evidence
synthesis; a process of
combining multiple
studies together to
give one effect size
wi...
Advantages of meta-analysis?
• When there are conflicting studies.
• To produce a precise effect estimate.
• Large power s...
Types of systematic reviews
Intervention
review
Systematic reviews
of observational
studies
Diagnostic review
Clinical tri...
Steps of systematic review
Research
Question
Eligibility
criteria
Searching
literature
Screening
Quality
assessment
Presen...
#1: Formulating the Research Question
1. Specific “narrow scope”.
2. PICO
 Population
 Intervention
 Comparator
 Outco...
#2: Define eligibility criteria
Inclusion
criteria
Exclusion
criteria
Criteria based on which you will include
some studie...
Major domains of eligibility criteria
• Age range? Minimum sample size? Gender?
• Definition of condition? Disease stage?P...
How to write a Systematic Review Protocol?
Open the lecture notes (PRISMA-P checklist)
Your Turn,
NOW!
1- Formulate a research question
2- Choose relevant keywords
3- Define eligibility criteria
GROUP
ACTIVITY
#3: Searching the literature
Medical
Electronic
Databases
Conference
Proceedings
Relevant
Books and
Reviews
Identify relevant
keywords
Improve your
search keywords
[MESH]
Formulate the
search strategy
• Try to involve all studies ...
Do NOT forget:
1- To remove duplications if you retrieve studies from
different sources. [Using EndNote or Mendeley]
2- Se...
#4: Screening of retrieved studies
Screening
titles
Screening
abstracts
Screening
full-text
articles
How to perform screening?
Hand screening (Printed titles/abstracts)
Online sheet (e.g. Google spreadsheet)
Using End Note ...
Hand screening of printed titles/abstracts
• CITATION
• DECISION
• REASON “code”
Using a printed screening form
for each p...
Screening using online sheet (titles ONLY)
Screening using EndNote software
Semi-automated screening (Abstrackr)
Semi-automated screening (Covidence)
It is important that each step (Literature search,
screening, selection of full text article, data extraction,
and quality...
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Systematic review and meta analaysis course - part 1

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This presentation is the first part from Ahmed Negida's course titled: Systematic review and Meta-analysis.

Published in: Health & Medicine

Systematic review and meta analaysis course - part 1

  1. 1. Systematic Review and Meta-analysis AHMED SAID NEGIDA Part 1
  2. 2. Learning objectives 1. Why systematic reviews? 2. Systematic reviews vs. Literature review 3. Types of Systematic reviews 4. Steps of systematic reviews 5. Writing a systematic review protocol 6. Searching the literature, exporting results and checking duplications 7. Strategies for abstract screening
  3. 3. Steps of systematic review Research Question Eligibility criteria Searching literature Screening Quality assessment Presenting findings
  4. 4. Summarize the Literature Less Bias: Transparent and reproducible More power Source for Evidence-Based practice Why systematic reviews?
  5. 5. No, because about 32% of a set of studies with at least 1,000 citations were either contradicted by or reported stronger effects than subsequent studies. The NEED for systematic reviews Can we reply on high quality, well-designed, single studies rather than systematic reviews?
  6. 6. Yes. For example: A systematic review about sudden infant death syndrome and sleeping position could have saved 60,000 infant lives in the United Kingdom, Europe, the United States, and Australia if it was performed any time after 1970. Systematic reviews may have a life-saving potential !
  7. 7. Systematic reviews are rapidly replacing traditional narrative reviews as a means to summarize and appraise literature.
  8. 8. Systematic review vs. Literature review Systematic review Literature review EVIDENCE High evidence Low evidence METHOD Systematic steps according to a detailed protocol Expert opinion “no protocol and no systematic steps” BIAS Low bias High bias REPRODUCIBILITY Yes Not reproducible SCOPE Narrow scope Wide scope
  9. 9. Meta-analysis Quantitative evidence synthesis; a process of combining multiple studies together to give one effect size with a large power (large sample size). Combined Effect Estimate Study 3 Study 1 Study 2
  10. 10. Advantages of meta-analysis? • When there are conflicting studies. • To produce a precise effect estimate. • Large power so a small but clinically significant effect size will be apparent.
  11. 11. Types of systematic reviews Intervention review Systematic reviews of observational studies Diagnostic review Clinical trials Observational studies (Cross sectional, Cohort, and case control) Diagnostic test accuracy studies (DTA)
  12. 12. Steps of systematic review Research Question Eligibility criteria Searching literature Screening Quality assessment Presenting findings
  13. 13. #1: Formulating the Research Question 1. Specific “narrow scope”. 2. PICO  Population  Intervention  Comparator  Outcome 3. Supported by clear eligibility criteria. ?
  14. 14. #2: Define eligibility criteria Inclusion criteria Exclusion criteria Criteria based on which you will include some studies and exclude others
  15. 15. Major domains of eligibility criteria • Age range? Minimum sample size? Gender? • Definition of condition? Disease stage?Population • Form of drug? Mode of administration? Dose? • First line of second line? Accepted adjuvants?Intervention • Placebo? or active comparator? • Form of drug? Mode of administration? Dose?Comparator • Efficacy measured on (….. / ….. / ….). • Safety “reporting adverse events”…..Outcome • Interventional? Randomized or Quasi experimental? • Observational? Prospective or retrospective? • Minimum follow up duration? Cross over or parallel? Study design
  16. 16. How to write a Systematic Review Protocol? Open the lecture notes (PRISMA-P checklist)
  17. 17. Your Turn, NOW! 1- Formulate a research question 2- Choose relevant keywords 3- Define eligibility criteria GROUP ACTIVITY
  18. 18. #3: Searching the literature Medical Electronic Databases Conference Proceedings Relevant Books and Reviews
  19. 19. Identify relevant keywords Improve your search keywords [MESH] Formulate the search strategy • Try to involve all studies relevant to your research question. • Search multiple databases. • Seek help from experts in your specialty. #NOW: open lecture notes (Searching Medical Electronic Databases)
  20. 20. Do NOT forget: 1- To remove duplications if you retrieve studies from different sources. [Using EndNote or Mendeley] 2- Search results and screening are reported as PRIMA flow diagram. [Using Review Manager] #NOW: open lecture notes (Checking duplicates + PRIMA flow diagram)
  21. 21. #4: Screening of retrieved studies Screening titles Screening abstracts Screening full-text articles
  22. 22. How to perform screening? Hand screening (Printed titles/abstracts) Online sheet (e.g. Google spreadsheet) Using End Note software Semi-automated (using Abstrackr @CEBM)
  23. 23. Hand screening of printed titles/abstracts • CITATION • DECISION • REASON “code” Using a printed screening form for each paper Reason code is used to save time from repeating reasons. See our example in lecture notes (Page no )
  24. 24. Screening using online sheet (titles ONLY)
  25. 25. Screening using EndNote software
  26. 26. Semi-automated screening (Abstrackr)
  27. 27. Semi-automated screening (Covidence)
  28. 28. It is important that each step (Literature search, screening, selection of full text article, data extraction, and quality assessment) is done by multiple reviewers to avoid possible individual errors. Disagreements should be resolved by discussion or by opinion of another reviewer.

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