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Absolute risk reduction versus Relative risk reduction

13K views 9 replies 9 participants last post by  organo14 
#1 ·
160 people in placebo , 80 died .
200 people in Drug X , 50 died .
what % of deaths were prevented by DRug X ?
 
#8 ·
absolute risk reduction= subtract the risk ratio of drugX from risk ratio of placebo.

ARR= 80/160 - 50/200 = 0.5 - 0.25 = 0.25 = 25%

so, drug X reduced the absolute risk of death by 25% in the population


relative risk reduction = divide the risk ratio of placebo group with risk ratio of drugX

RRR= 50/200 / 80/160 = 0.5/0.25 = 2

so, relative risk of death with drug X is 2 times less likely than in the placebo group. Or
in other words, placebo group has 2 times more risk of death than the drug X.
 
#9 ·
RRR

absolute risk reduction= subtract the risk ratio of drugX from risk ratio of placebo.

ARR= 80/160 - 50/200 = 0.5 - 0.25 = 0.25 = 25%

so, drug X reduced the absolute risk of death by 25% in the population

relative risk reduction = divide the risk ratio of placebo group with risk ratio of drugX

RRR= 50/200 / 80/160 = 0.5/0.25 = 2

so, relative risk of death with drug X is 2 times less likely than in the placebo group. Or
in other words, placebo group has 2 times more risk of death than the drug X.
RRR= ARR/Control Group .25/.5= .5 = 50 percent RRR
Correct me if im wrong
 
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