3. Measures of Morbidity/Mortality (incidence, prevalence, mortality, lethality) *by example*) Flashcards
What is Incidence?
the frequency of occurrences of disease, injury, or death in the study population during the time period of the study. Also known as absolute risk.
What is the Incidence formula?
Incidence = # of new cases / # of people at risk
(per unit of time)
what is Cumulative incidence?
the total number of cases of an epidemic disease reported over time
what is Incidence density (incidence rate)?
refers to the number of new events per person-time (per personmonths or person-years)
what is Prevalence (prevalent cases)?
the number of individuals in a defined population who have a specific disease or condition, at a given point in time
what is the formula for Prevalence?
Prevalence = # of existing cases / Total # of people in a population
(per unit of time)
What is Point prevalence?
refers to prevalence at a specific point in time.
What is Period prevalence?
refers to the number of persons who had a given disease at any time during a specified time interval;
It is the sum of the point prevalence at the beginning of the interval plus the incidence during the interval.
In period Prevalence, what happens if survival time increases?
- incidence = no change
- prevalence = increases
In period Prevalence, what happens if mortality increases?
- incidence = no change
- prevalence = decreases
In period Prevalence, what happens if recovery time is faster?
- incidence = no change
- prevalence = decreases
In period Prevalence, what happens if there is extensive vaccine adminstration?
- incidence = decreases
- prevalence = decreases
In period Prevalence, what happens if risk factor decrease?
- incidence = decreases
- prevalence = decreases
What is Mortality rate?
it is a measure of the frequency of occurrence of death in a defined population during a
specified interval.
What is Morbidity?
it is a measure of the frequency of occurrence of illness in a defined population during a
specified interval.
