Chapter 6: The natural history of disease

Question 1

What makes a test a “good test”?

Answer 1

Validity and reliability

Question 2

What happens when there is no test?

Answer 2

Several criteria must be met before a diagnose or treatment effort can be made.

Question 3

Prognosis: Person Years

Answer 3

Are a unit of time used to express the length of time individuals are observed

Question 4

Prognosis: Observed Survival

Answer 4

-Uses the actual observed survival experiences of patients.
-Uses lifetable to estimate risk of populations (probability of death)

Question 5

What is the formula for calculating the 5-year probability of survival?

Answer 5

5 yr probability of survival= p1 x p2x p3 x p4 x p5

Question 6

Life tables

Answer 6

Try to account for losses to follow up, as well as losses due to mortality.

Question 7

Kaplan-Meier Method

Answer 7

Identify the exact point in time at which each death/ even occurred.

Question 8

Median Survival

Answer 8

Defined as the length of time that half the population survives.

Question 9

Relative Survival

Answer 9

Defined as the ratio of the observed to expected deaths in a population.