Lesson 4: The Epidemiologic Approach Flashcards
What are the 4 steps in the epidemiologic approach?
- Define the case
- Count cases/health eventsand describe them using the descriptive epidemiology
- divide the number of cases by the apropriate denominatior to calculate rates
- Compare these rates over time or for different groups of people
What is a case definition?
a set of standard criteria for classifying whether a person has a particular health condition
What does a case definition consist of?
- Clincal criteria (confirmatory lab results or combination of symtoms/sings)
- sometimes limitations on time, place and person
What is Defining a Case?
developing a case defnition which is used to find and collect information about the case-patients
What are some examples for case classification?
- confirmed case
- probable case
- possible case
- suspect case
- not a case
What is a probable case
Acute onset of at least 3/4 features
What is a confirmed case?
there are signs and symptoms plus laboratory confirmation
What is a possible case?
Acute onset 2/4 features plus a physician diagnosis
What is suspect case?
Unexplained disease
What is not a case?
Failure to fulfill the criteria for a confirmed, probable, possible, or suspect case
What is a sensitive case definition?
A definition that is broad or loose used in the hope of capturing more or all of the ture cases
What is a sensitive case definition used for?
It is used for rare but potentially severe communicable diseases where it is important to identify every possible case
s the disadvantage of a sensitive case definition?
it might sometimes include other illnesses
What is a strict case defintion?
It requries that everyone with symptoms be tested ensuring all people counted have the disease
When is a strict case definition used?
It is used when an investigator studying the causes of a disease outbreak wants to be certain everyone is included in a study had the disease
