Exam II Lecture 12 EBM Mahoney Flashcards
Number needed to treat
How many patients must be treated to see either a benefit or harmful effect.
Number needed to treat (NNT) in a random control trial
Subtract the Control event rate - the Experimental Event Rate (EER)
1/ CER-EER
CER and EER need to be in percentages.
What NNT (Number needed to treat) is considered good?
If the number needed to treat is <4
Equation for number needed to harm (NNH)
1/ EER - CER
Experimental event rate - Control event rate
The higher the number needed to harm (NNH) the…..
Better!
In contrast, the number needed to treat must be low (<2) to be considered good.
What is the statistic of choice for case controlled studies?
Odds ratio!!
What is the clinical definition of the odds ratio?
The ratio of the odds of having the adverse outcome in the treatment group relative to the odds of having an adverse in the control group.
What odds ratio will indicate a bad outcome caused by the treatment?
Odds ratio greater than 1 beans that the bad outcome is caused by the treatment.
What does it mean if the odds ratio is 1?
The adverse event is no more likely to occur with than without the exposure.
Odds ratio that indicates the bad outcome is prevented by the treatment?
<1
It is related to the number needed to treat (NNT)
How do you determine the PEER or Patient Expected evet rate?
of control patients having the adverse event / # of control patients not having the adverse effect (Bottom two boxes)