lect 8-10

Question 1

define risk (exposed and unexposed)

Answer 1

probability of outcome in exposed A/(A+B)
probability of outcome in unexposed C/(C+D)

ratio of the risk from 2 different groups

Question 2

define ARR

Answer 2

the risk difference of the outcomes among exposed that can be attributed to the action exposure (risk difference)

Question 3

define Risk Ratio (RR)

Answer 3

risk in exposed/risk in non-exposed

Question 4

what do you need to look for when interpreting ratios (RR/OH/HR)

Answer 4

direction of words
magnitude
group comparison

Question 5

how do you calculate ARR

Answer 5

A-B

ie: ramipril=14%, placebo=17.8%
so ARR=3.8%

Question 6

how do you calculate RRR

Answer 6

(ARR)/R of the unexposed

Question 7

how do you calculate NNT

Answer 7

1/(ARR)

Question 8

how do you interpret NNT

Answer 8

number of whole patients needed to be treated to experience the studied event outcome

Question 9

how to calculate odds exposure in cases compared to odds of exposure in controls

Answer 9

[(A/C)/(B/D)]

Question 10

define attributable differences & attributable risk/proportion

Answer 10

risk of the exposed (attributable risk)