POPH192 L20-22

Question 1

Case

Answer 1

People w/ outcome

Question 2

Controls

Answer 2

People w/ out outcome

Question 3

Case-Control Strengths

Answer 3

• Rare/slow to develop outcomes
• acute/transient exposures
• multiple exposures
• temporal sequencing
• CAN be quick & inexpensive

Question 4

Case-Control Limitations

Answer 4

• can only study one outcome
• difficult to select appropriate control group
• can be susceptible to selection & recall bias

Question 5

Odds Ratio

Answer 5

Assess odds of exposure cases & odds of exposure in controls (can’t calculate incidence)
- null value = 1

Question 6

Measures of Association

Answer 6

• odds ratio
• risk ratio
• risk difference
• rate ratio

Question 7

Odds of Exposure Cases

Answer 7

cases exposed
(divided by)
cases not exposed

Question 8

Odds of Exposure Controls

Answer 8

controls exposed
(divided by)
controls not exposed

Question 9

Odds Ratio Calculation

Answer 9

Odds of exposure cases
(divided by)
Odds of exposure controls

Question 10

Odds Ratio Interpretation (4)

Answer 10

• exposed group
• value
• outcome
• comparison group

Question 11

OddsRatio > 1

Answer 11

Exposure is a risk factor to developing the outcome

Question 12

OddsRatio < 1

Answer 12

Exposure is a protective factor against developing outcome

Question 13

Randomised Controlled Trial

Answer 13

Participants randomly allocated to groups/always have a comparison (control) group/testing effect of interventions/treatments
- Treatment group & control group compared to find out succession of treatment/intervention

Question 14

Randomisation

Answer 14

Stops confounding
- randomly assigning participants to intervention OR control

Question 15

Protect Randomisation

Answer 15

• Large numbers: More likely to lead to balanced groups w/ large number of participants
• Concealment of Allocation
• Intention-to-treat analysis

Question 16

Intention-to-treat Analysis

Answer 16

Includes all randomized patients, regardless of their adherence with the study criteria; regardless if they stayed or not

Question 17

RCT Strengths

Answer 17

• best way to evaluate in intervention
• can calculate incidence & thus give measure of association for treatments
• Gives strongest info for causal association

Question 18

RCT Limitations

Answer 18

• ethical issues
• not all exposures are suitable to be randomly allocated
• difficult to achieve binding
• potential loss to follow up & non-adherence
• resource intensive
• highly selective - need to meet all inclusion criteria & willing

Question 19

Beneficence

Question 20

Non-maleficence

Question 21

Informed Consent

Question 22

Justice

Question 23

Clinical Equipoise

Question 24

Conflicts of Interest