The document provides an overview of the steps involved in conducting a systematic review, including forming a team, developing a search strategy and inclusion/exclusion criteria, searching databases, extracting and analyzing data, and reporting results. Key aspects of systematic reviews discussed include developing a protocol, conducting a comprehensive literature search, assessing risk of bias, and synthesizing evidence both qualitatively and quantitatively through meta-analysis when possible. Challenges of systematic reviews include the time and resources required as well as ensuring methodological rigor.

1. OVER VIEW ON SYSTEMATIC
REVIEW
Peter D. Daud
Kibong’oto Infectious Diseases
Hospital
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2. Overview of steps in SRMA
 Introduction
Steps in systematic review
Data extraction
 Quality assessment
Analysis and interpretation
Report & writing
Publishing
Challenges/drawbacks
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3. Systematic review
• Is defined as a review using a systematic methods to
summarize evidence on pre defined question with a
detailed and comprehensive plan of study.
• A systematic review attempts to collate all empirical
evidence that fits pre-specified eligibility criteria in
order to answer a specific research question.
• It uses explicit, systematic methods that are selected
with a view to minimizing bias, thus providing more
reliable findings from which conclusions can be drawn
and decisions made.
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4. Why Systematic review??
• The amount of evidence from (health science) research is massive.
massive abundance of studies has incresed strickingly over the last
decade, a well conducted SR is a feasible considered solution for
keeping clinician with current evidence based medicine.
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5. Why systematic review
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6. Key characteristics
 A clearly stated set of objectives with pre-defined eligibility criteria
for studies
 An explicit, reproducible methodology
 A systematic search that attempts to identify all studies that would
meet the eligibility criteria
 An assessment of the validity of the findings of the included studies,
for example through the assessment of risk of bias
 A systematic presentation, and synthesis, of the characteristics and
findings of the included studies
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7. Meta-analysis
• Many systematic reviews contain meta-analyses.
• Meta-analysis is the use of statistical methods to summarize the
results of independent studies.
• By combining information from all relevant studies, meta-
analyses can provide more precise estimates of the effects of
health care than those derived from the individual studies
included within a review .
• They also facilitate investigations of the consistency of evidence
across studies, and the exploration of differences across studies.
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8. Step 1:Team formation & topic
selection
Like any other study design, the formation of a
team is crucial before the start of the study.
The team must formulate a review/search
question
The formulated qn should be :- feasible,
interesting, noval, ethical and relevant,logical.
-common tools used ( PICO/SPIDER).
Qualitative study: SPIDER is valid
PICO: SR/MA.
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9. • A SR needs to be conducted by a team of experts
(not single-handedly by only one researcher)
• such team may include:
Expertise in the clinical content area
E.g. both a surgeon and pathologist may be included
Expertise in systematic review methods
A member with experience in conducting systematic reviews
Expertise in searching for relevant evidence3
E.g. a librarian / information specialist
Expertise in quantitative methods
E.g. a statistician to conduct a meta-analysis
Other expertise as appropriate
The team for conducting the SR
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10. SR team
 Whatever the motivation for undertaking a review the preparation and conduct should be rigorous.
 • A search of resources such as the DARE database should be undertaken to check for existing or
ongoing reviews, to ensure a new review is justified.
 • A review team should be established to manage and conduct the review. The membership should
provide a range of skills, including expertise in systematic review methods, information retrieval,
the relevant clinical/topic area, statistics, health economics and/or qualitative research methods
where appropriate.
 • Formation of an advisory group including, for example, health care professionals, patient
representatives, services users and experts in research methods may be a requirement of some
funding bodies. In any event, it may be valuable to have an advisory group, whose members can be
consulted at key stages.
 • The review team may wish to seek advice from a variety of clinical or methodological experts,
whether or not an advisory group is convened.
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11. What types of questions can be asked?
Question Ideal study types
Intervention Randomized controlled trial
Frequency/rate
(burden of illness)
Cross-sectional study or consecutive
sample
Aetiology and risk Cohort study
Prediction and prognosis Cohort study
Diagnostic accuracy Random or consecutive sample
Phenomena Qualitative research
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12. The proces of a systematic review
Define purpose and scope
Develop research question and protocol
Systematic review team and management
Determine inclusion and exclusion criteria
Conduct literature searches
Select studies for inclusion
Extract data from studies and constructing evidence tables
Assess quality and applicability of studies
Qualitative analysis
Quantitative analysis
Assess and rate the strength of the body of evidence
Prepare and disseminating the review
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13. Considerations before conducting a SR
Topic and scope
• Is a systematic review of the given topic relevant
(will it provide or update necessary evidence)?
(Cholera: what isthe genetic diversity of vc in E/A)
• Have recent (high quality) SR been published or
initiated (does protocols exist)?
(DARE, CDSR, PROSPERO, PubMed ect.)
Purpose, topic and scope of the SR
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14. II: Preliminary search and idea
validation
• It is recommended to do a preliminary search to identify
relevant articles, ensure the validity of the proposed idea
Avoid duplication of previous idea/qn.
• Ensure that we have enough articles for analysis.
• Ensure themes is focusing on relevant important h/care
issues, consider global needs, reflect current sciences.
• To do this you can start a simple search in (Pubmed, google
scholar,research gate …etc.
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15. III: Inclusion& Exclusion criteria
Any systematic review it is clear to have a well
defined ( Ex/incl criteria)
Eligibility criteria are based on PICO/SPIDER
approach, study design and date .
Exclusion criteria are unrelated, duplicated,
unavailable full text, care report, case series,
abstruct only papers.
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16. III:Search Strategy
• A standard search strategy is used in Pubmed
then later it is modified according to each specific
databases to get the best relevant results.
• Search strategy are constructed to include free
text terms ( eg in the tittle & abstruct and any
appropriate subject index eg MeSH)
• The improvement of search terms is made while
doing a trial search & looking for another relevant
terms
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17. Search strategy
Search ((cholera) AND (((waves) OR
("lineage"[All Fields])) OR (biotypes))) AND
(((((((("east africa"[All Fields]) OR
("tanzania"[All Fields])) OR ("rwanda"[All
Fields])) OR ("south sudan"[All Fields])) OR
("kenya"[All Fields])) OR ("uganda"[All
Fields])) OR (burundi)) OR (zanzibar))
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18. IV: Search databases, import all
results to a library:
• According to AMSTRA guidelines at least two
data bases has to be used in the SR/MA
• As you increase the number of data bases you
increases the yield and accurace.
• The ordering of data bases pendends mostly
on the review qn.
• NB: Riviews sholud consider to choose
relevant data bases according to the topic.
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19. Proposed data based:
1. Pub Med
2. Scopus
3. Web of science
4. EMBASE
5. GHL
6. VHL
7. Cochrane
8. Google scholar
9. mRCT
10. POPLINE
11. Clinical trial.gov
12. SIGLE
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20. Studies can be located using a
combination of the following
approaches
 Searching electronic databases
 Visually scanning reference lists from relevant studies
 Hand searching key journals and conference
proceedings
 Contacting study authors, experts, manufacturers, and
other organizations
 Searching relevant Internet resources
 Citation searching
 Using a project Internet site to canvas for studies
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21. Drawbacks and limitations
• Systematic reviews can be conducted badly
• Bias in the selection of included papers (e.g.
Language)
• Not conducting a comprehensive search in the
most relevant databases, including grey
literature, hand searching
• No properly combining results of different
studies.
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22. Challenges in doing SRMA
• Seems a daunting task
• Seems difficult to understand
• Consumes time
• Lack of guidance
• Many unforeseen obstacles
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23. Systematic review protocol
 Preparation of a SR protocol can help minimize potential bias in the review process
(e.g. Cochrane requires publication of the protocol – any changes must be documented
and reported in a specific section of the completed review)
 The Cochrane Handbook1 and IOM2 both have standards / requirements for SR protocols
 Developing the protocol is an iterative proces
 It is recommended that researchers send it to the principal investigator (PI) to
revise it, then upload it to registry sites
 Protocal registration at aealy stage guarantee transparency in the reseach process.
CAMP BELL COLLABORATION/ PROSPERO
S/R protocols writting & registration
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24. Systematic review protocol may include descriptions
of*:
• The context and rationale for the SR
• Inclusion / exclusion criteria
• Outcomes, time points, intervention and
comparison groups
• Search strategy
• Procedures for study selection
• Data extraction strategy
Contents of S/R protocols
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25. Systematic review protocol may include descriptions of:
• Process for identifying and resolving disagreements
between researchers in study selection and data
extraction decisions
• The approach for critically appraising individual studies
• The method for evaluating the body of evidence
• Planned analyses of differential treatment effects
according to according to patient subgroups
• A timetable for conducting the review
*
Contents of SR protocols
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26. Selecting studies for inclusion
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27. Extracting data and constructing
evidence tables
• Data extraction: the process of selecting and recording
relevant data from primary publications
• Data extraction errors are frequent and can compromise
the results
• Common problems: erroneous number of patients,
means, standard deviations, and sign for the effect
estimate
• Recommendations
– Two reviewers, working independently, to extract quantitative and
other critical data
– Link publications from the same study to avoid including data from
the same study more than once
– Use standard data extraction forms
– Pilot test the forms and process
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28. What to extract?
• For analysis , Study ID , Location, year , Study
design • Sample size , PICO (TS)
• Confounders adjusted , Effect size (95% CI)
Subgroup results ,Other relevant For quality
assessment
• Risk of bias , Selection (Allocation concealment,
Sequence, Randomization) ,Blinding,
Measurement bias ,Attrition
• Reporting , Sample size adequacy,
Representativenes
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29. Assessing quality and applicability of
studies
• Critical appraisal – the process of systematically
evaluating the validity of research and its relevance to
specific clinical situations.
– Study quality, internal validity
– Applicability, external validity or generalizability
• Evidence hierarchy and risk of bias
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30. Tools for QA
• Tools for QA depends on the study design
ROB-2 …….Cochrane tool for RCT
NIH……….. For observation& Crossectional study
QUADRAS-2….. For diagnostic studies
QUIOS……………For prognostic studies
CARE………………for case report
ToxR……………….For vivo&vitro studies
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31. Quality appraisel
The quality assessment of the evidence of included studies can be
guided by various quality appraisal tools adjusted to the design
qualities of different study types:
• Quality appraisal of clinical guidelines: AGREE II
• Quality appraisal of systematic reviews of the effect of
interventions: AMSTAR
• Quality appraisal of RCT’s: Cochrane Risk of Bias Tool
• Quality appraisal of non-randomized studies (incl. observational
studies): ROBINS-I
• Quality appraisal of primary diagnostic studies: QUADAS-2
• Quality appraisal of primary prognostic studies: QUIPS
• Quality appraisal of qualitative studies: See recommendation from
the Cochrane Collaboration
• http://videncentret.dk/Forskerservice/Vaerktoejer?sc_lang=en
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32. Qualitative analysis
• Little guidance on how to perform a good qualitative
analysis
• The clinical context of a study includes the participants,
setting, interventions and their administration, and
outcomes and their determination
– Interpreting clinical characteristics of the studies
(subgroup analysis may be necessary)
– Interpreting methodological characteristics of studies
• In-depth understanding of the studies
• Nelson, H. D. (2014). Systematic Reviews to Answer
Health Care Questions. Lippincott Williams & Wilkins
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33. Quantitative analysis
• Decision to combine studies
• Choice of effect measures differs by the type of outcome
data
• Assessing statistical heterogeneity (graphical methods)
• Models for combining studies (most commonly used:
fixed effects or random effects)
• Exploring heterogeneity when present
• Publication bias assessed
• Sensitivity analysis to evaluate the impact of decisions
and assumptions
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34. Data analysis
Reviews use different methods for combining and
summarizing findings of the included studies.
Before summarinzing there is important step :
Data cleaning in extraction sheet/online library
Analyst orgnanise data in extraction sheet in a
form that can be read by analytical software.
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35. Be aware of predatory journals
• The number of predatory journals has risen dramatically
during the past 5 or 10 years. Predatory journals have
increased their publication volumes from 53,000 in 2010 to an
estimated 420,000 articles in 2014 (Shen and Bjork, 2015).
• Unscrupulous publishers are exploiting the open-access (OA)
publishing model by producing fake, scam, unscholarly and
deceptive journals.
• The peer review process in these journals is corrupted and is
either non-existent or minimal. Huge profits are made on the
basis of author publication fees, which seem to be the main
criteria for publication.
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36. Manuscript writing/Revision and
submission to journals
Before preparing the findings for public
consumption ( Posters/conferences etc.
Do the following:-
• Send to PI
• PI to Reveiws ( reply to comments)
• Send to appropriate journals
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37. The proces of a systematic review
Define purpose and scope
Develop research question and protocol
Systematic review team and management
Determine inclusion and exclusion criteria
Conduct literature searches
Select studies for inclusion
Extract data from studies and constructing evidence tables
Assess quality and applicability of studies
Qualitative analysis
Quantitative analysis
Assess and rate the strength of the body of evidence
Prepare and disseminating the review
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38. • Any SR/MA must follow the widely accepted
Preferred Reporting Items for Systematic
Review and Meta-analysis statement (PRISMA
checklist 2009)
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39. Useful resources – systematic reviews
• Cochrane Collaboration
– http://www.cochrane.org/
– http://www.cochrane.org/docs/irmg.htm
• Centre for Reviews and Dissemination
http://www.york.ac.uk/inst/crd/
handbook for conducting systematic reviews,
– http://www.york.ac.uk/inst/crd/methods.htm
– Searching for systematic reviews
http://www.york.ac.uk/inst/crd/revs.htm
• EPPI-Centre – Stages of a review
– http://eppi.ioe.ac.uk/cms/Default.aspx?tabid=89
• SCIE - The conduct of systematic research reviews for SCIE knowledge
reviews
– http://www.scie.org.uk/publications/details.asp?pubID=111
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