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  #1  
Old 05-23-2011
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Stats Number Needed To Treat Calculation?

a study is done to see if raloxifene will reduce the incidence of vertebral fractures in post menopausal women.
Results are
RALOXIFENE --- PLACEBO
no. of women in study group 2557 --- 2576

no. of vertebral fractures 138 --- 260
(5.4%) --- (10.1%)

based on these results how many women need to be treated to prevent one vertebral fracture?

A) 100/5.4=18.5
B) 100/10=10
c) 100/10+5.4=6.5
D) 100/10-5.4=21
E) 100/10*5.4=2
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  #2  
Old 05-23-2011
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Arrow

its D.
NNT= 1/absolute risk reduction.
Absolute risk reduction =event rate(control)-event rate(tt)
=10.1%-5.4%
=4.7%=0.047
NNT=1/ARR
=1/0.047
=21.2
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  #3  
Old 12-18-2011
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The answer to this question according to NBME feedback is E, although cannot understand why??????

SOMEONE PLEASE EXPLAIN:sorry:
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  #4  
Old 12-18-2011
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D ans..in which NBME ??
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  #5  
Old 12-18-2011
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NBME 7,its answer E,cannot understand how but
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