Clinical Epidemiology 2 - Frequency Flashcards
Fraction of a group of people possessing a clinical condition or outcome at a given point in time
Prevalence
Point vs Period Prevalence
Point - single point in time
Period - defined period
Fraction of a group of people initially free from outcome of interest that develops condition over given point in time (new cases)
Incidence
Formula for incidence
New cases in period of time / Susceptible people without disease at beginning of period
Formula for prevalence
Existing cases at defined time / Population (All people, cases and non-cases)
Type of study used to measure incidence
Cohort Study
Type of study used to measure prevalence
Cross-Sectional Study
Relationship between duration of disease, prevalence, and incidence
Prevalence/Incidence = Duration (steady state) Prevalence = Incidence x Duration
In words: Higher duration = more likely to be caught by prevalence study
Proportion of people having a disease who die from it
Case fatality rate
Proportion of people having a disease who survive it
Survival Rate
Formula for infant mortality rate
Number of deaths in year of children <1 yr
over
Number of live births in the same year
Formula for perinatal mortality rate
Number of stillbirths and deaths in first week of life per 1000 livebirths
Formula Maternal Mortality Rate
Number of maternal deaths related to childbirth in a given year
over
Number of live births in the same population during same year
TRUE OR FALSE: Infant mortality rate and maternal mortality rate are approximations of incidence?
TRUE
Approach to studying incidence in a dynamic population
Incidence Density (Person Years) Take into account time each person is part of the population/at risk
