docswapna
Forum Senior
Topics: 61
Posts: 229
|
raloxifene placebo
no. of women in study group 2557 2576
no. of vertebral fractures 138(5.4%) 260(10.1%)
Based on these results how many women should be treated to prevent 1 fracture?
a) 10/5.4=8.5
b) 100/10.1=10
c) 100/(10.1+5.4)=6.5
d) 100/(10.1-5.4)=21
e) 100/(10.4*5.4)=2
|
| klimt
Forum Guru
Topics: 27
Posts: 605
|
I go with D
___________________
Traveler, there are no roads. Roads are made by walking.
|
| Addicudo
Forum Guru
Topics: 124
Posts: 608
|
HUmm I'd with D too ..
As No. of women receving Placebo and having a fracture 10.1%
No. of women receving Raloxifene .. still having fractures 5.4% ..
So therefore we minus the Normal rate of fracture occuring without drugs 10.1 to the women who took raloxifnee and still got a fracture .. Meaniing that 5.4% would get Fractures irrespective of them taking Raloxifene .. !! therefore ..
10.1-5.4 ..
And as to why we divide this by 100 ..  Aint sure . !!
___________________
... Idle hands are the DeVilS play ground ...
|
| smal
Forum Guru
Topics: 140
Posts: 727
|
i dont get it.
i understand from this qt...is how many women r to be treated to prevent 1 #.so it treating 5.4 would prevent 100 #,to prevent 1 we've 100/5.4
guys i go for A
___________________
remedy for weakness is not brooding over it ,but thinking of strength.
|
| Musuq
Forum Guru
Topics: 103
Posts: 425
|
Number Needed to Treat (NNT)
Definition: The NNT is the number of patients who need to be treated in order to prevent one additional bad outcome. It is the inverse of the Absolute Risk Reduction (ARR).
How to Calculate NNTs
NNT = 1/ARR
ARR = |CER - EER|
where CER = control group event rate
EER = experimental group event rate
Sample Calculation
The results of the Diabetes Control and Complications Trial* into the effect of intensive diabetes therapy on the development and progression of neuropathy indicated that neuropathy occurred in 9.6% of patients randomised to usual care and 2.8% of patients randomised to intensive therapy.
The number of patients we need to treat with the intensive diabetes therapy to prevent one additional occurrence of neuropathy can be determined by calculating the absolute risk reduction as follows:
ARR = |CER - EER| = |9.6% - 2.8%| = 6.8%
NNT = 1/ARR = 1/6.8% = 14.7 or 15 We therefore need to treat 15 diabetic patients with intensive therapy to prevent one from developing neuropathy.
|
| Musuq
Forum Guru
Topics: 103
Posts: 425
|
In our question:
CER = control group event rate = 10.1
EER = experimental group event rate = 5.4
Thus:
NNT = 1/ARR -> 1/ARR = 1/|CER - EER|% = 1/(10.1-5.4) % = 100/10.1 -5.4
I get it now, thanks Addicudo! and docswapna!
Edited by Musuq on 10/13/06 - 03:15 AM
|
| smal
Forum Guru
Topics: 140
Posts: 727
|
thanks guys
that was a nice exp musuq
___________________
remedy for weakness is not brooding over it ,but thinking of strength.
|
|
| |
| | | | | | | |
