Biostats - nurden

[ArchivalUser]

thank you for the question

[ArchivalUser]

A study is done to determine if raloxifene prevents fractures. Results

Raloxifene: 138/2557 vertebral fractures (5.4%)
Placebo: 260/2576 vertebral fractures (10.1%)

How many women need to be treated with raloxifene to prevent one vertebral fracture?

a) 100/5.4 = 18.5
b) 100/10.1 = 10
c) 100/(10.1 + 5.4) = 6.5
d) 100/(10.1 - 5.4) = 21
e) 100/(10.1 x 5.4) = 2

[ArchivalUser]

d?

[ArchivalUser]

d.

ARR= Control event rate MINUS Exposure event rate.

ARR= .101 (10.1%) - .054 (5.4%) = .047

NNT= 1/ARR = 1/.047 = 21............ think about the nickel .047 = .05 cents so 1/.05= 1/(1/20)= 20 (simple math) so pick answer close to 20.

ALSO: Don't have to move the decimal point so D is correct answer = 100/ (10.1-5.4) if we keep numbers in PERCENT form.

[ArchivalUser]

thank you

[ArchivalUser]

great one

[ArchivalUser]

answer is D thank you

[ArchivalUser]

thanks

[ArchivalUser]

please post more questions, thanks

[ArchivalUser]

how do you prepare for biostat ethics etc?