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[ArchivalUser]

evaluate the efficacy of new drug superstatin the results are as followed treated with superstatin and have MI 10 no MI 990 treated with placebo and have MI25 no MI 975 what is # needed to treat to prevent one MI with superstatin? a.1 b . 2 c.2.5 d. 25 e 40 f 67 g 83

[ArchivalUser]

no one?????????????

[ArchivalUser]

2? I had a question like this on the exam and didn't know the answer. This might help:
http://en.wikipedia.org/wiki/Number_needed_to_treat

[ArchivalUser]

thankyou rei this is from uw they say u have to find absolute risk reduction but if we are going to find it will be 25% but then do with super statin and result come 67 so i am really confuse why they are using superstatin treeted pt having MI do u under stand ??????/

[ArchivalUser]

no, the absolute risk reduction is 1.5% (25/1000 - 10/1000, which is 2.5% -1%). then i think you have to calc the relative risk reduction (1.5/2.5 = 15/25), and the number needed to treat is the inverse of that, meaning 25/15 = 1.6, so NNT = 2. That's how i calculated it. What is the correct answer?

[ArchivalUser]

ans is 67 u are up to ans 1.5% than they use a formula NNT = 1/1.5%=66.6=67

[ArchivalUser]

oh, that's right. I looked at the definition of NNT again and it is the inverse of the absolute risk reduction, not the rel risk reduction. I told you i didn't know this one

[ArchivalUser]

NNT=1/ARR
ARR= events in placebo/1000 x 100 (-) events in Tx/1000 x 100

so,placebo- 25/1000 x 100= 2.5%

Tx- 10/1000 x100= 1

ARR= 2.5 (-) 1= 1.5%

therefore,NNT= 1/ 1.5 % or 1/ 0.015 = 66.6 i.e almost 67%