2.3 Case Control studies Flashcards Preview

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Flashcards in 2.3 Case Control studies Deck (27)
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1
Q

What type of study is Case control studies?

A

Observational studies

2
Q

What do case control studies allow?

A

researcher to be a passive observer of natural events occurring in cases who are compared with controls

3
Q

What are case control group assignments based on?

A

Disease status

4
Q

What are case control studies useful for?

A

Rare disease or investigating an outbreak

5
Q

What key word tells us that we are dealing with observational studies?

A

Randomly selected. Not randomized

6
Q

What key word tells us that we are dealing with interventional studies?

A

Randomized

7
Q

On the epi table, for case controls, what are we looking at?

A

A+C and B+D

8
Q

What are 3 reasons to use a case control study?

A

Unable to force group allocation. Limited resources and disease is rare.

9
Q

Case control studies are conducted in a what type of fashion?

A

Retrospective

10
Q

What are the 5 strengths of case control studies?

A
  1. Good for multiple exposures of one outcome. 2 Usefull for rare diseases. 3 Determines associations (not causation). 4. Good with ethics. 5. Good when disease has a long induction/latent period.
11
Q

What are 5 weaknesses of case control studies?

A
  1. Cant demonstrate causation. 2. confounders. 3. They are retrospective. 4. Have lots of bias. 5. Limited data due to retrospective nature.
12
Q

How are the selection of cases for case control study designs?

A

want the most detailed criteria possible. So we hope these cases are accurate. Find out how did they find out they were cases. Missclaffication can be a problem. Still an error.

13
Q

What is the recall counterfactual theory?

A

All else being equal except outcome. Requires exchangeablilty to other determinants of outcome

14
Q

What is the most difficult part with case control studies?

A

Control selection

15
Q

Why is the control selection the hardest?

A

The way the controls are selected is a major determinant in whether any conclusion is valid. Internal validity,, selection bias.

16
Q

Where can control groups come from? 3 ways

A

Population, institutional/organization/provider, spouse/relatives/friends.

17
Q

True or False? An individual can function as both an exposed and unexposed individual in the same study?

A

True

18
Q

How can a pt be in both the exposed and unexposed group in the same study?

A

Via outbreak investigation with multiple exposures or case-crossover

19
Q

What are Nested case control studies?

A

like case control, but nested and comes form another study. Developed as case study after another study.

20
Q

What are three ways Nested case control studies sample from other studies?

A

Survivor, base and risk set sampling.

21
Q

What is survivor sampling?

A

Sample of survivors at END of study period

22
Q

What is base sampling?

A

Sample of non diseased individuals at START of study period

23
Q

What is risk-set sampling?

A

Sample of non diseased individula DURING study period at same time when case was diagnosed.

24
Q

What is selection bias?

A

To the way subjects are chosen for study

25
Q

What is recall bias?

A

pts recall past events differently

26
Q

What is individual matching?

A

Matches individuals based on specific patient based characterisitcs.

27
Q

What is group matching?

A

Proportion of cases and proportion of controls with identical characteristics are matched. requires cases be selected first