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Old 04-25-2015
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hii!!

I have a question... this is what I understood from kaplan... are NNT and NNH calculated the same way?

Example:
incidence of cancer in smokers: 10/100
incidence of cancer in non smokers: 1/100

Attributable risk:
10-1= 9/100

NNT/ NNH:
100/9= 11

so in that example I assume the NNT and NNH are the same

is that accurate?

NNT: number needed to treat
NNH: number needed to harm
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Old 04-26-2015
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Number needed to treat(NNT) is calculated based on the absolute risk reduction(ARR), it is inverse if ARR. Basically this is where we talk about how many patients we should treat to PREVENT one case of disease.(Question will talk about placebo treatment vs new treatment)

Number needed to harm(NNH) is calculated based in attributable risk(AR), it is inverse of AR. This is how we calculate how many people need to be exposed to a risk factor to DEVELOP one case of disease. (Question will talk about risk factor exposure)
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Old 04-26-2015
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Thanks so much Hassanah

I didn't find absolute risk reduction on kaplan... where did you read it from? or maybe i misread it

thanks for replying
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Old 04-26-2015
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Yeah its not mentioned in kaplan but you can read it from First Aid.
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Old 03-11-2016
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Number needed to treat is calculated by dividing 1 by the absolute risk reduction --> 1/([C/C+D]-[A/A+B])

Number needed to harm is calculated by dividing 1 by the attributable risk --> 1/([A/A+B)-[C/C+D])


i would upload flashcards of this, but i dont have enough posts do so. if you have an android, you can check out the flash cards on an app called EpiStats. its an app im working on and trying to improve.
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