trials and that

Question 1

what is the gold standard trial to assess efficacy?

Answer 1

-randomised controlled trials

Question 2

what are examples of experimental studies?

Answer 2

• systemic reviews (combining RCTs)

- randomised control trials (RCTs)

Question 3

what are examples of observational analytical studies?

Answer 3

• cohort
• case control
• cross sectional study

Question 4

what are examples of observational descriptive studies?

Answer 4

• case report

- case series

Question 5

what is difficult to determine from a non randomised control?

Answer 5

-causality

Question 6

what is a cohort study?

Answer 6

-consists of a greoup or population followed over time, enrolled at a baseline with comprehensive measurement, followed up for a fixed length of time

Question 7

how to calculate the risk of disease in exposed?

Answer 7

Question 8

how to calculate the risk of disease in unexposed?

Answer 8

Question 9

how to calculate relative risk?

Answer 9

Question 10

what would a relative risk >1 indicate?

Answer 10

-exposure is harmful

Question 11

what would a relative risk <1 indicate?

Answer 11

-exposure is protective

Question 12

what would a relative risk= 1 indicate?

Answer 12

-exposure similar to exposed

Question 13

what would a relative risk= 3.0 indicate?

Answer 13

-3 fold increase in risk of outcome in exposed compared to unexposed

Question 14

what does a relative risk of 1.7 mean?

Answer 14

70% increase

Question 15

what does a relative risk of 0.8 mean?

Answer 15

20% decrease

Question 16

what is a prospective cohort study?

Answer 16

-cohort followed forward in time from present

Question 17

what is a retrospective cohort study?

Answer 17

-cohort formed in the past and followed up to the present

Question 18

what are the advantages of a cohort study?

Answer 18

• Temporality -> exposure precedes outcome
• No recall bias
• Can study multiple outcomes associated with rare exposures
• It can measure incidence

Question 19

what are the disadvantages of a cohort study?

Answer 19

• Requires large investment of time, human and financial resources if prospective
• Requires large sample sizes – unless the risk period is very long
• Loss to follow-up bias – removal of susceptibles
• Inefficient for rare diseases
• Uncontrolled confounding