systematic reviews-intro
TRANSCRIPT
Yale UniversityCushing/Whitney Medical Library
An Introduction to Systematic Reviews
Charles J Greenberg, MLS, Med, AHIPFulbright Specialist Project #5104
Yerevan, Armenia
[email protected]@gmail.com
(203) 737-2960
Session Outline
What is a Systematic Review? How to locate existing Reviews Typical Steps in Conducting a
Review How can a librarian help? Guides and Sources
A systematic review attempts to identify,
appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a given research question.
Researchers conducting systematic reviews use explicit methods aimed at minimizing bias, in order to produce more reliable findings that can be used to inform decision making.
Definition Source: Cochrane Collaboration
What is a Systematic Review?
Why are systematic reviews important? In the Evidence
Pyramid, systematic reviews represent qualitative value for published research. Note the pyramid suggests that fewer are created.
A PubMed@Yale Clinical Queries Search can find published systematic reviews
The Cochrane Library
a library subscription collection of databases that contain different types of high-quality, independent evidence. Cochrane Database of Systema
tic Reviews (CDSR)CDSR is the most recognized database. Other databases include a register of controlled clinical trials, a research methodology register, technonolgy assessment, evaluation studies, etc.
Before you begin…. Is a systematic review
necessary? Does one already exist?
Consider the level of commitment and follow through that is necessary
Do you have a team or partners?Can you recruit colleagues?Do you have library support? ( I will address what the library can do later)
1st Step- Define the Question• Framing the question in a way which lends
itself to searching• PICO: The situation or population, the
intervention, comparison (if appropriate; may be implied) and the desired outcome.
P: patients arrive with acute low back pain I: warm or heatC: [cold or nothing]O: Pain ReliefAnswerable Question: In patients with low back pain, is heat an effective therapy for pain relief?
Check to see if one or more systematic reviews already exist for your question
If you don't have a HINARI password or don't want to log in, you can view Cochrane Library, The as a member of the public. You will not have full access, unless your institution participates in other arrangements.Click here to proceed to Cochrane Library, The without logging in.
Confirm subject of review, based your formulated question.
• The problem should be specified in a clear, unambiguous and structured question before beginning the review work.
• Once the review question has been set, only modify if alternative ways of defining the populations, interventions, outcomes or study designs produce a new question.
Produce all the specifications (details) to define the review protocol
• Conceptual discussion• Confirm research question• Establish Search Strategy• Study Inclusion and exclusion criteria• Qualitative standard for assessment• Data extraction procedure • Data synthesis procedure• Record keeping• Project timetable
PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses http://www.prisma-statement.org/
2nd step : Conduct a thorough search, considering these sources
• Cochrane Controlled Trials Register(CCTR)
• Electronic databases• Trial registries not covered by CCTR• Citation lists from retrieved articles• Hand searching of key journals• Pharmaceutical companies• Personal communication with experts in the field
3rd step : Select the studies that are relevant to the protocol
• Review the titles and abstracts as a first pass, then obtain full textHave more than one reviewer check each article for initial eligibility, based on the agreed criteria.
Develop a strategy to deal with disagreements.
Keep a log of excluded studies, with reasons for study exclusion.
4th step : Appraise the quality of studies with established qualitative labels (1)
level I: systematic review of well-designed randomized controlled trialslevel II: randomized controlled trialslevel III: non-randomized clinical trialslevel IV: well-designed non-experimental studieslevel V: opinions of respected authorities, based upon clinical evidence, descriptive studies, or reports of expert committeeslevel VI: someone's opinion
Example of qualitative labels: Cochrane Levels of study quality
Consider quality assessment by more than one reviewer
Use a simple scale or checklist, like Cochrane levels (previous slide example)
Assess for quality factors or their concealment, like treatment allocation, blinding, and handling of patient attrition
Consider blinding your reviewers to authors, institutions, and journals.
4th step : Appraise the quality of studies with the established qualitative labels (2)
5th Step: Extracting data from studies
• Design and pilot a data extraction form
• Consider data extraction by multiple reviewers (if method is sound, same result)
• Consider blinding extractors to author, institutions, and journal identities (eliminate bias in extraction)
6th Step: Analyze and present results
Tabulate studies and examine composite view
Consider sources of heterogeneity (were the studies selected too dissimilar?)
Consider meta-analysis of all clinical trials
Consider sensitivity analysis (Is there common strength and relevance?)
Make a list of excluded studies that could be shared with explanation
What Can a Librarian Help with?
• As an expert searcher, a librarian can interact with investigators to develop the search terms required for a comprehensive search strategy in multiple appropriate sources. This includes recommending overlooked resources.• This involves meeting with designated members of the team, or at times the whole team.
What Can a Librarian Help with?
• As an organizer and analyzer, the librarian can effectively manage the articles and document the search, retrieval, and archival processes. • Accurate methodology documentation
is required in a systematic review.• Maintain a record of search strategies• Re-run the strategies to identify new
research within scope.• The research team will determine
validity and applicability of new emerging research.
What Can a Librarian Help with?
• The Librarian can also:• Recommend learning materials for doing systematic reviews
• Obtain and organize access to full text for the team.
• Update records, if asked and appropriate.
• Write up details of the full search and methodology of obtaining and excluding studies
Charlie Greenberg
Thank You for your Time and Attention