Systematic reviews Flashcards
Why are systematic reviews important?
They objectively summerise large amounts of information, identifying gaps in medical research and identifying beneficial or harmful interventions.
Used to define methods in subsequent studies.
Often conducted by experts in the field
They deliver clear and comprehensive of available evidence on a given topic
What is the difference between SR and meta analysis?
Meta analysis is restricted to the process of statistical synthesis which may or may not be part of a systematic review.
Systematic review attempts to gather all available empirical research by using clearly defined systematic methods to obtain answers to a specific question.
A meta-analysis is the statistical process of analysing and combing results from several similar studies.
What is a systematic review?
Systematic reviews aim to provide a comprehensive, unbiased synthesis of many relevant studies in a single document using rigorous and transparent methods.
A SR does not seek to create new knowledge but rather synthesise and summarise existing knowledge.
Retrieve international evidence and synthesise the results of research into evidence to inform practice and policy. Follow a structured research process which require rigorous methods to ensure the results are reliable and meaningful to end users.
SR allows analysis of different research methods and types to provide a synthesis of available evidence
What do systematic reviews include?
Methods to minimise the risk of error and bias during the review process.
Explicit and exhaustive reporting of methods used in the synthesis is a necessity and hallmark of any well conducted SR.
Such rigour distinguishes them from traditional literature reviews
As a scientific enterprise, a SR will influence healthcare decisions and should be conducted with the same rigour expected of all research.
Why do a systematic review?
What are the aims?
A SR may be undertaken to review whether current practice is based on evidence and to address any uncertainty in practice that may be occurring.
Resolve conflicts of evidence
Aims:
- Uncover the international evidence
- Confirm current practice or address any variation
- Identify areas for future research by identifying what evidence is not available
- Investigate conflicting results
- Produce statements to guide decision-making
What is the difference between literature reviews and SR?
Literature review:
- Choices made for inclusion of studies can be subjective - rely on authors knowledge or experience
- Conducted according to no stated methodology
- Limited searching
- Leads to risk of bias or systematic error
- Unreproducible and not transparent
SR
- Informed by an a priori protocol
- Structured research process
- Steps are taken to reduce bias
- Process is systematic and exhaustive of searching for information
- Transparent and reproducible methods
What are the SR standards?
What do they provide guidance on?
Reporting standards exist to guide review reports
PRISMA (Preferred reporting items for SR and MA)
- Provides a checklist for review authors
- Tells how to report as SR
ENTREQ (Enhancing transparency in reporting the synthesis of qualitative research)
- For qualitative research
Cochrane handbook and methodological expectations of Cochrane intervention reviews (MECIR)
Provide guidance for:
- Initiating a SR
- Finding and assessing individual studies
- Synthesising the body of evidence
- Reporting SR
- Mainly focus on quantitative reviews
What are the characteristics of a high quality SR?
Clearly articulated objectives and questions
Inclusion and exclusion criteria, stipulated a priori (in the protocol) - determine the eligibility of studies
Comprehensive search to identify all relevant studies (published and unpublished)
Critical appraisal of the included studies
Analysis of data extracted from the included research
Presentation and synthesis of the findings extracted
Transparent reporting of the methodology and methods used to conduct the review
What are the steps in a SR?
Structured process of a SR:
Formulate review question
Define inclusion and exclusion criteria
Locate studies
Select studies
Assess study quality
Extract data
Analysis, summary and synthesis of relevant studies
Present results
Interpret results, establish confidence in body of evidence (GRADE, ConQual)
What are the types of SR?
Meta analysis of randomised controlled trials (gold standard in evidence of effectiveness)
Effectiveness reviews
Qualitative reviews
Cost/ economic reviews
Prevalence or incidence reviews
Diagnostic test accuracy reviews
Eitology and risk reviews
Textural synthesis reviews
Mixed methods reviews
Umbrella reviews
Scoping reviews
What are ways of searching literature?
Attempt to locate all published and unpublished evidence relevant to a review question
General approach:
- Identifying appropriate resources and sources to search
- Developing search strategies
- Searching bibliographic databases
- Looking for unpublished literature
- Hand searching
- Reference list
Search must be accurately documented and reproducible
