BIOSTATS and Pharmacoeconomics

Question 1

BIOSTATS:

What is the equation for relative risk (RR)?

Answer 1

RR = risk in tx group
—————
Risk in control

Question 2

BIOSTATS:

How do you calculate relative risk reduction? (RRR)

Answer 2

RRR = 1 - RR
= % risk control - % risk tx
———————–
% risk control

Question 3

BIOSTATS:

What is RRR?

Answer 3

Relative risk reduction is the % the risk of event is reduce by being in the treatment group

Question 4

BIOSTATS:

What is ARR?

Answer 4

ARR is absolute risk reduction or the difference in risk that can be attributed to the treatment group

Question 5

BIOSTATS:

How do you calculate absolute risk reduction (ARR)

Answer 5

ARR = % risk in control group - % risk in tx group

Question 6

BIOSTATS:

What is NNT?

Answer 6

NNT is the number needed to treat in order to theoretically prevent one event

Question 7

BIOSTATS:

How do you calculate NNT?

Answer 7

NNT = 1/ARR
= 1
————————-
(% risk control - % risk tx)

Question 8

BIOSTATS:

What is the equation for “risk?”

Answer 8

Risk = # subjects w/ event
——————–
# subject in that arm