Measures of Risk and Benefit

Question 1

What is the difference between absolute risk and relative risk?

Answer 1

If 1/100 people who don’t smoke get a disease

but 2/100 people who DO smoke get a disease

absolute risk = 2/100 people

relative risk = 100% more likely to develop disease or 2x more likely

… so the absolute risk is very small compared to the relative risk

Question 2

what do absolute and relative risk give us understanding of?

Answer 2

absolute risk = provides us with context

relative risk = provides us with a risk factor comparison

Question 3

interpret the following relative risks

>1

< 1

=1

Answer 3

>1 = risk is higher in exposed group

<1 = risk is higher in baseline group (group not exposed)

= 1- risk is the same in both groups

Question 4

what is the risk difference?

Answer 4

the difference in risk between people who have and have not a risk factor

Question 5

what is the attributable risk?

Answer 5

percentage of cases among those exposed to a risk factor which can be attributed to the risk factor

Question 6

what does NNT and NTN stand for?

Answer 6

NNT = emphasises the benefits of treatment - number needed to treat

NNT = number treated needlessly