Systematic Reviews and Meta-analysis
What is a narrative review?
A qualitative summary of evidence on a topic. This involves informal and subjective methods to collect and interpret information.
What is a systematic review?
A review that identifies, appraises, and synthesizes all the empirical evidence that meets pre-specified eligibility criteria to answer a given research question. Explicit methods are used to reduce bias in order to produce more reliable findings that can be used to inform decision-making.
What is the process of conducting a systematic review?
(1) Formulate a systematic review team of at least 2 people (2) Clearly define the research question (3) Use PICOS question as a prompt (4) Clear selection criteria for inclusion. Develop the protocol. (5) Comprehensive search to identify studies (6) Conduct the search (7) Retrieve relevant papers (8) Screen and select papers that meet established criteria. Print abstracts, read abstracts and retrieve relevant papers (9) Critical appraisal/evaluation. Evaluate methodologic quality of selected studies to reduce risk of bias (10) Pre-defined synthesis. Analyze and synthesize findings. (11) Transparent reporting
How do you read a Forest Plot? How is it constructed? What is its purpose?
A Forest plot is a standard way of expressing individual results of studies such as relative risk, odds ratio, mean difference between groups. The forest plot depicted above represents a meta-analysis of 5 trials that assessed the effects of a hypothetical treatment on mortality. Individual studies are represented by a black square and a horizontal line, which corresponds to the point estimate and 95% confidence interval of the odds ratio. The size of the black square reflects the weight of the study in the meta-analysis. The solid vertical line corresponds to 'no effect' of treatment - an odds ratio of 1.0. When the confidence interval includes 1 it indicates that the result is not significant at conventional levels (P>0.05).
What is PRISMA?
A checklist of items to include when reporting a systematic review. Preferred Reporting Items of Systematic Reviews and Meta-Analysis.
What is a meta-analysis? What are the two stages in a meta-analysis?
A meta-analysis has 2 steps. (1) Extraction of data from individual studies (2) Calculation of result from pooled data between studies. Calculation of confidence intervals for each study. Calculation of pooled average results across all studies.
How many people review the systematic review prior to its publication?
A minimum of 2 primary reviewers. If there is no consensus, a 3rd party resolution is needed.
What are the biases that can influence the outcome or quality of a systematic review?
Attrition bias: loss of subjects across comparison groups. This is relevant for studies with addressed through intention to treat analysis. Detection bias: occurs if outcome assessment differs across comparison groups. Selection bias: systematic differences between those selected and those not selected. Confounding bias: extraneous variables contribute to bias Allocation bias: differences due to the way treatment groups are assembled Performance bias: differences in provision of care to experimental and control groups in study. Reporting bias: Systematic differences between reported and unreported findings
Who is Archibald Cochrane? What is he known for and why?
He is the creator of Cochrane Reviews, which are systematic reviews of research in healthcare and healthcare policy that are published in the Cochrane Database of Systematic Reviews.
What is the relationship between a meta-analysis and a systematic review?
If there is not enough sample size to pool data, you report results of systematic review. If there is large enough sample size to pool data (small number of studies with large N
What are the 3 types of systematic reviews published in Cochrane reviews?
Intervention reviews, diagnostic test accuracy reviews, and methodology reviews. Intervention reviews: assesses the benefits and harms of interventions used in healthcare and healthcare policy Diagnostic test accuracy reviews-assess how well a diagnostic test performs in diagnosing and detecting a certain disease Methodology reviews-address issues relevant to how systematic reviews and clinical trials are reported
What are rating scales used for a systematic review?
JADAD scale PEDro scale- Physiotherapy Evidence Database Scale. Used in rehab and medical literature QUADAS: Reviews studies of diagnostic test accuracy
What databases are searched when conducting a systematic review?
MEDLINE, EMBASE, CINAHL, Web of Science, EBM Review
How is the research question for a systematic review defined?
Well-formulated questions will guide many aspects of the review process, including determining eligibility criteria, searching for studies, collecting data from including studies, and present findings. Identify and define variables.
