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
What is a disadvantage of a strict case definition?
Everyone requires testing, understimation of the total number of cases
What would health officials use if they wanted to stop a case of the plague ASAP?
A sensitive case definition
What is the Epidemiolic Approach acronym and what does each letter stand for?
DCDC
Define
Count
Divide
COmpare
How are rates defined?
Rates are defined by (the number of cases ÷ the size of the population) per unit of time
