Week 7 Flashcards
(22 cards)
What is a systematic review?
A critical analysis of the literature on a clearly formulated question using systematic, transparent methods to identify, appraise, and synthesize relevant research.
Strengths of systematic reviews?
Reduces bias through strict criteria
Increases statistical power
Improves generalizability
Summarizes evidence efficiently
Aids clinical and policy decisions
Weaknesses of systematic reviews?
Vulnerable to publication bias
Heterogeneity of studies
Dependent on quality of included studies
Time- and resource-intensive
Not always suitable for poorly defined questions
How can weaknesses be addressed in systematic reviews?
Use comprehensive search strategies
Assess heterogeneity
Perform subgroup/sensitivity analysis
Critically appraise studies
What is a meta-analysis?
A statistical technique to combine results of multiple independent studies to estimate the overall effect of an intervention or exposure.
Strengths of meta-analyses?
Greater statistical power
Narrower confidence intervals
Resolves conflicting study results
Generates new hypotheses
Enhances generalizability
Weaknesses of meta-analyses?
Prone to publication bias
Heterogeneity can affect results
Quality depends on input studies
Risk of combining “apples and oranges”
Statistically complex
How to critically appraise a meta-analysis?
Clear question and criteria
Assesses publication bias
Explores heterogeneity
Uses appropriate statistical methods
Transparent reporting
What defines an observational study?
A study where no variables are manipulated. Researchers observe and assess naturally occurring relationships between exposures and outcomes.
What are the types of observational studies?
Cohort (prospective)
Case-control (retrospective)
Cross-sectional (snapshot in time)
Strengths of observational studies?
Real-world relevance
Ethical for studying harmful exposures
Can assess multiple outcomes
Useful for hypothesis generation
Weaknesses of observational studies?
Cannot prove causation
Confounding variables
Susceptible to selection, recall, and observer bias
Temporal ambiguity
How to address observational study weaknesses?
Careful design and participant selection
Use of statistical adjustments
Sensitivity analyses
Triangulation of data sources
What is a prospective study?
Follows participants forward in time, measuring exposures before outcomes.
Pros of prospective studies?
Establishes time sequence
Less recall bias
Cons of prospective studies?
Expensive
Time-consuming
Risk of loss to follow-up
What is a retrospective study?
Looks backward in time, using past data after outcomes have occurred.
Pros of retrospective studies?
Efficient and cheaper
Useful for rare conditions
Cons of retrospective studies?
Recall and selection bias
Harder to establish cause and effect
What did the VBA stroke case-control study conclude about chiropractic care?
No excess risk of stroke from chiropractic care compared to primary care; likely a result of patients seeking care for early dissection symptoms.
What type of study was used in this example?
Population-based case-control and case-crossover study.
