Case-Control Flashcards
1
Q
What is a Case-Control Study?
A
- •Design Characteristics
Select participants as cases and controls
Data on exposure collected just after group allocation
2
Q
Inclusion of Incident vs. Prevalent cases in case-controls
A
- Prevalent cases more easily attainable
- With prevalent cases, potential for factors being related to survival or duration of disease, not causal
- Survival prior to disease could be an issue for incident cases too
- Interpretation of exposure preceding disease
3
Q
Selection of controls in case-control
A
- Want controls as similar to cases on all factors other than the exposure of interest
- Minimize biases: selection bias, confounding, information bias
- Using these principals: study base principal, deconfounding, comparable accuracy
- Study efficiency and cost also considerations
4
Q
Issues in Ascertainment of Cases in case-control
A
- Well‑defined diagnostic criteria, representative of all cases
- Sources (hospital, general population)
- Incident or prevalent cases
5
Q
Issues in Selection of Controls in case-control study
A
- Theoretical considerations (representative of the reference population; matched or comparable for certain variables)
- Practical considerations (feasibility and cost)
- Sources of controls
- population of defined area
- hospital patients
- neighbors
- siblings, spouses or other relatives
- friends or associates of cases
6
Q
Handling Potential Confounding Factors in case-control study
A
- In the process of selecting controls
- Matching
- stratification (group or frequency matching)
- pairing ‑‑ individual matching
- In the data analysis
- Stratification
- Adjustment
- Matching
7
Q
pros of case-control study
A
- Cheap, quick and easy
Multiple Exposures
8
Q
cons of case-control study
A
- Rare exposures
Limited number of outcomes
9
Q
Biases in case-control study
A
- Temporal bias
Recall bias
Selection bias
* interviewer bias
10
Q
Measure of association in case-control
A
odds ratio = (a/c) / (b/d)
