Epidemiology Lecture 5 Prognosis

Front 1

What is the definition of prognosis?

Back 1

Prediction of the expected outcome of a disease with or without treatment

Front 2

Ideally, a prognosis should include what five things?

Back 2

1) The variability in course relative to treatment options
2) A time reference
3) A risk of treatment- related death (or other untoward reaction)
4) Cost
5) The nature of the benefit attainable

Front 3

What is the definition of case fatality?

Back 3

% of patients w/ a disease who die of it

Front 4

What is the definition of survival rate?

Back 4

% of patients surviving a defined period of time from some point in the course of their disease

Front 5

What is the definition of a response?

Back 5

% of patients showing some evidence of improvement after an intervention

Front 6

What is the definition of remission?

Back 6

% of patients entering a phase in which disease is no longer detectable

Front 7

What is the definition of recurrence?

Back 7

% of patients who experience a return of disease after a disease-free interval

Front 8

What are the 2 questions that provide the rationale for creating a life table?

Back 8

1) What is the likelihood of surviving for x years after diagnosis?
2) What is the likelihood of surviving another year, given that the patient has already survived for y years since diagnosis

Front 9

How do you calculate the probability of surviving 2 years?

Back 9

P1 x P2

Front 10

What is the probability of surviving 3 years?

Back 10

P1 x P2 x P3

Front 11

*What does a survival curve show?

Back 11

Cumulative survival over time

Front 12

When comparing multiple survival curves, what does a steeper slope mean?

Back 12

Steeper slope= worse survival
-Survival rate VS number of years after diagnosis

Front 13

Why does the slope of a survival curve flatten out towards the right side of the graph?

Back 13

Because even if survival remains constant it still appears flatter as the population decreases

Front 14

What does the y-value mean when interpreting a survival curve?

Back 14

CUMULATIVE survival up to that time point

Front 15

What is the Kaplan- Meier method of prognosis evaluation?

Back 15

Where takes into consideration of the time that each animal survived, don't lose any patient information- graph is percent surviving (y-axis) VS months after enrollment (x-axis)

Front 16

What is the equation and meaning of relative survival rate?

Back 16

Relative survival rate= observed survival in patients with disease/ expected survival if disease were absent
-"how much WORSE off is this patient due to the disease?"

Front 17

What is something that the relative survival rate doesn't take into consideration?

Back 17

Relative survival rate doesn't change w/ age or sex i.e. says cancer is no more severe in older patients

Front 18

*****The only population that you can generalize from when gathering population data is which population?

Back 18

The population from which the study sample was drawn
-Big difference b/w population based and clinical based

Front 19

What are prognoses based on?

Back 19

Quantitative expressions of natural history of disease

Front 20

Ideally, a prognosis should include what 3 things?

Back 20

1) Variability of outcomes and side effects associated w/ different treatments
2) A time line
3) Cost

Front 21

What are 2 methods for handling data on natural history of disease?

Back 21

1) Life tables
2) Kaplan-Meier method

Front 22

What are 3 pitfalls of a prognoses?

Back 22

1) Biases due to diagnostic methods
2) Observed vs relative survival rate
3) Bases due to non- randomly selected study population