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Old 08-29-2012
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Stats Biostatistics Q..

You are asked to evaluate the efficacy of new lipid lowering drug marked as "superstatin" results of randomized control trial at 5yrs are given at the table below
Treatment with Superstatin Treatment with Placebo
M.Infarction 10 25
No M Infarction 990 975

what is the number needed to treat to prevent one myocardial infarction with superstatin.

p:s i can't post the answer options because i wanna know how it's solved. Thanks!!!.... i'll post when it's done.
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Old 08-29-2012
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Default 66.6

Attributable risk- 25/1000-10/1000= 15/1000

No needed to treat= 1000/15=66.6
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Old 08-30-2012
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is that the correct asnwer?
isnt the forumla a/ a+b - c/c+d
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Originally Posted by pathophysio1 View Post
is that the correct asnwer?
isnt the forumla a/ a+b - c/c+d
Yea pathphisio thatz the correct answer..
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Old 08-30-2012
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koolkiller,
In the 2x2 table, we're supposed to take 'a' as Diseased and Exposed right? So in this question, the 'a' cell is going to be patients with MI & who took placebo? Didn't understand how to arrive at that. Would appreciate your help, thanks!
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NNT = 1/ARR= numbb. of people who were treated with the drug and had a MI subtracted by the number of ppl who had a MI taking placebo that = ARR and then do 1 /ARR
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Default Hope it help

Quote:
Originally Posted by dockhi View Post
koolkiller,
In the 2x2 table, we're supposed to take 'a' as Diseased and Exposed right? So in this question, the 'a' cell is going to be patients with MI & who took placebo? Didn't understand how to arrive at that. Would appreciate your help, thanks!
I always get confused by this a and b stuff. So i just do my calculations according to question.
Attributable risk- Incidence rate of exposed group minus incidence rate of non exposed group.
So exposed group will be those who are on superstatin.
In this question, if we make 2X2 table,
then,
Superstatin placebo
MI 25 10
non MI 975 990
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Old 08-31-2012
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Quote:
Originally Posted by koolkiller88 View Post
I always get confused by this a and b stuff. So i just do my calculations according to question.
Attributable risk- Incidence rate of exposed group minus incidence rate of non exposed group.
So exposed group will be those who are on superstatin.
In this question, if we make 2X2 table,
then,
Superstatin placebo
MI 25 10
non MI 975 990
Alright, makes sense.. But doesn't the question state that 10 people had MI when they were on Superstatin,and 25 people had MI when they were on placebo? Sorry to sound dumb here, but really appreciate the help!
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Originally Posted by dockhi View Post
Alright, makes sense.. But doesn't the question state that 10 people had MI when they were on Superstatin,and 25 people had MI when they were on placebo? Sorry to sound dumb here, but really appreciate the help!
Ya true, Just took a proper look. Ok you can change it. I am never good at 2X2 tables.
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Quote:
Originally Posted by koolkiller88 View Post
Ya true, Just took a proper look. Ok you can change it. I am never good at 2X2 tables.
Regardless, you taught me how to USE the formula. Thank you! Btw, when are you taking the Exam? I'm scheduled for October. Feel lousy!!
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Regardless, you taught me how to USE the formula. Thank you! Btw, when are you taking the Exam? I'm scheduled for October. Feel lousy!!
I scheduled for Nov. YA "lousy feeling" is a common thing will all share.
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