Biomarkers & surrogate markers

Question 1

Define biomarkers

Answer 1

Any objective, quantifiable characteristic of biological processes

Question 2

Advantages of using biomarkers as a clinical endpoint

Answer 2

• Simpler and less expensive to measure than clinical endpoints
• Can be analysed repeatedly
• Can be ethically more appropriate than measuring clinical endpoints

Question 3

Disadvantages of using biomarkers as a clinical endpoint

Answer 3

A disease biomarker may not be useful if:

It is measured inaccurately
Doesn’t predict a clinical endpoint

It’s altered by confounding factors

Question 4

What is a surrogate marker/outcome?

Answer 4

A measure of effect of a specific treatment that may correlate with a real clinical endpoint but does not necessarily have a guaranteed relationship.

It is a substitute for clinically meaningful outcomes

Question 5

List the T-test assumptions

Answer 5

• Data is continuous
• The sample data have been randomly sampled from a population
• The groups are normally distributed
• Normal/similar variance between groups.

Question 6

What is standard deviation?

Answer 6

How spread out values are in the data set

Question 7

What is standard error?

Answer 7

Standard deviation of the mean in repeated samples from a population