Treatment effect (MCIDs and Risk)

Question 1

Types of approaches for MCIDs of objective measures

Answer 1

• anchor based
• distribution based
• consensus-based

Question 2

What is an anchor-based approach for MCID

Answer 2

global rating of change.

compare changes on a measure over time to patients rating of their overall change during that period

(measure change + ask patients if they think they have changed by a meaningful amount)

-> minimally important change

Question 3

What is a distribution based approach for MCID

Answer 3

Based on the spread of the data in a study and dependent on the reliability of the measurement instrument

-> minimum detectable change

Question 4

What is a consensus-based approach for MCID

Answer 4

Group of experts in the area question change then adjust and repeat until consensus is obtained over how much change represents the MCID

Question 5

Types of dichotomous variables

Answer 5

• absolute risk reduction
• number needed to treat
• relative risk reduction

Question 6

What is absolute risk reduction?

Answer 6

the difference in risk between groups (control risk minus intervention risk)

Question 7

What is number needed to treat?

Answer 7

the inverse of absolute risk reduction
number needed to treat to prevent the event of interest
(smaller number the better)

Question 8

What is relative risk reduction?

Answer 8

risk reduction as a proportion of the control group
(ARR divided by risk of control group)
over inflates benefit