Exam II Lecture 12 EBM Mahoney

Question 1

Number needed to treat

Answer 1

How many patients must be treated to see either a benefit or harmful effect.

Question 2

Number needed to treat (NNT) in a random control trial

Answer 2

Subtract the Control event rate - the Experimental Event Rate (EER)

1/ CER-EER

CER and EER need to be in percentages.

Question 3

What NNT (Number needed to treat) is considered good?

Answer 3

If the number needed to treat is <4

Question 4

Equation for number needed to harm (NNH)

Answer 4

1/ EER - CER

Experimental event rate - Control event rate

Question 5

The higher the number needed to harm (NNH) the…..

Answer 5

Better!

In contrast, the number needed to treat must be low (<2) to be considered good.

Question 6

What is the statistic of choice for case controlled studies?

Answer 6

Odds ratio!!

Question 7

What is the clinical definition of the odds ratio?

Answer 7

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.

Question 8

What odds ratio will indicate a bad outcome caused by the treatment?

Answer 8

Odds ratio greater than 1 beans that the bad outcome is caused by the treatment.

Question 9

What does it mean if the odds ratio is 1?

Answer 9

The adverse event is no more likely to occur with than without the exposure.

Question 10

Odds ratio that indicates the bad outcome is prevented by the treatment?

Answer 10

<1

It is related to the number needed to treat (NNT)

Question 11

How do you determine the PEER or Patient Expected evet rate?

Answer 11

of control patients having the adverse event / # of control patients not having the adverse effect (Bottom two boxes)