Exam #1: Appraising Prognosis Studies

Question 1

What does prognosis refer to?

Answer 1

• The possible outcomes of a disease/ condition and the frequency with which they occur
• Also referred to as the “natural history” of an aliment

Question 2

What are prognostic factors?

Answer 2

Characteristics of a patient or population that can be used to more accurately predict the eventual outcome

• Demographics
• Disease-specific e.g. tumor stage
• Comorbidities

Question 3

What types of studies are best suited to evaluate prognosis?

Answer 3

• Cohort*****

- Case-control

Question 4

What are the questions to determine if a prognostic study is valid?

Answer 4

1) Are the patients representative?
2) Was follow-up long enough for the outcome of interest?
3) Were the outcomes measured “blind?”

Question 5

How do you determine the importance of a prognostic study?

Answer 5

1) Ask, what is the risk of the outcome over time?

2) How precise are the estimates of risk?

Question 6

What is “referral bias?”

Answer 6

This is an error that can occur when patients are selected from tertiary care centers (vs. primary) and are thus “sicker” compared to the general population/ controls