7 - Systematic Reviews & Meta-Analysis** Flashcards
Define systematic review
- Scientific investigation that focuses on a specific question and uses explicit, pre-specified scientific methods to identify, select, assess, and summarize the evidence
- May include a quantitative synthesis (meta-analysis) depending on the available data
Do systematic reviews only contain RCTs?
No
Difference between narrative review and systematic review regarding the question
- Narrative = often broad in scope
- Systematic = often a focused clinical question
Difference between narrative review and systematic review regarding the sources and searches
- Narrative = not usually specified; potentially biased
- Systematic = comprehensive source and strategy explicitly stated
Difference between narrative review and systematic review regarding the selection
- Narrative = not usually specified; potentially biased
- Systematic = criterion-based; uniformly applied
Difference between narrative review and systematic review regarding the appraisal
- Narrative = variable
- Systematic = rigorous critical appraisal
Difference between narrative review and systematic review regarding the synthesis
- Narrative = qualitative summary common
- Systematic = qualitative summary +/- meta analysis
Difference between narrative review and systematic review regarding the inferences
- Narrative = sometimes evidence-based
- Systematic = evidence-based
Why are systematic reviews needed?
- Massive number of publications
- Diverse language, different countries
- Studies can appear contradictory
- To establish clinical effectiveness, feasibility of an intervention, and to update guidelines
- To reduce delay of research to clinical practice
- To propose future research agenda
Describe the stages of the systematic review process
- Define a question
- Search the literature
- Assess the studies
- Combine the results
- Put the findings in context
Will a large or a small study produce a large confidence interval?
Small study
What is clinical heterogeneity?
Variability in the participants, interventions, and/or outcomes studied
What is methodological heterogeneity?
Variability in study design and risk of bias
What is statistical heterogeneity?
When observed intervention effects are more different from each other than we would expect due to random error alone
Which type of heterogeneity can you quantify?
Statistical
What tests can be done to determine if results are similar across studies?
- Eyeball test (do they look the same)
- Proportion of variation not due to chance (I squared); now the preferred estimate; 75-100% = considerable heterogeneity
- Test of “null hypothesis’ of no variation (p-value) – Cochrane chi-square; p < 0.1 = heterogeneity
What does n/N mean?
- n = number of px w/ the outcome
- N = total number of px in the group (either treatment or control group)
What are funnel plots?
- Detect bias in study selection
- Results of each study plotted against sample size
- In the absence of bias, plot will resemble a symmetrical, inverted funnel
Describe the acronym FAITH for determining if a review is good
- F = finding (did they find all studies)
- A = appraisal (did they use appropriate inclusion criteria)
- I = include (did they include valid studies)
- T = total up (did they synthesize similar outcomes)
- H = heterogeneity
Where do you report systematic reviews to on the equator network?
Prisma
