PE 2 Flashcards
What is the first stage of pharmacoepidemiology study design?
Selects a group of subjects for study.
What are the four basic types of associations that can be observed in a study?
- No association
- Artifactual association
- Indirect (confounded) association
- True causal association
What is a confounding variable?
A variable other than the risk factor and outcome under study which is related independently to both.
List the three possible types of errors in a study.
- Random error
- Bias
- Confounding
What criteria must be met for an association to be considered causal?
- Coherence with existing information
- Consistency of the association
- Time sequence
- Specificity of the association
- Strength of the association
What does coherence with existing information refer to?
Whether the association reflects other types of information available in the literature.
What is the hallmark of science associated with the consistency of the association?
Reproducibility in different settings.
What does time sequence mean in the context of causal associations?
A cause must precede an effect.
What does specificity of the association refer to?
Whether the cause ever occurs without the presumed effect and vice versa.
Define quantitative strength of the association.
It refers to the effect size, evaluated by the magnitude of the observed difference between study groups.
What is a dose-response relationship?
Strongly implies that an association is a causal association.
List the hierarchical order of study design options from least to most convincing.
- Case reports
- Case series
- Analyses of secular trends
- Case-control studies
- Retrospective cohort studies
- Prospective cohort studies
- Randomized clinical trials
What are case reports useful for in pharmacoepidemiology?
Raising hypotheses about drug effects.
What is a case series in the context of pharmacoepidemiology?
A descriptive study following a group of patients with a similar diagnosis over a period.
What are the strengths of a case-series design?
- High external validity
- No interference in treatment decisions
- Wide range of patients
- Inexpensive
- Takes little time
What is a limitation of case series?
Lack of a comparison group.
What do analyses of secular trends examine?
Trends in an exposure presumed to cause a disease and whether these trends coincide.
What is a case-control study?
Studies that compare cases with a disease to controls without the disease.
What are the five main notions guiding investigators in case-control studies?
- Define case criteria
- Controls from the same population
- Blind data gatherers
- Train data gatherers
- Address confounding
What is the main difference between cohort and case-control studies?
Cohort studies recruit based on exposure, while case-control studies recruit based on disease.
What statistic can be calculated from a cohort study?
Relative risk.
Define relative risk.
The ratio of the incidence rate of an outcome in the exposed group to that in the unexposed group.
What does a relative risk of greater than 1.0 indicate?
Exposed subjects have a greater risk of the disease than unexposed subjects.
What is excess risk?
The arithmetic difference between incidence rates.
What is the significance of randomized clinical trials?
They are the gold standard for establishing causal associations.
What are the advantages of randomized clinical trials?
- Most convincing design
- Controls for unknown confounders
What is a disadvantage of cohort studies?
They can be more expensive.
What is a limitation of case-control studies?
Control selection can be problematic.
What is a key characteristic of analyses of secular trends?
They lack control of confounding.
What is the primary use of case reports?
Generating hypotheses.
