Prevalence, Incidence, & Death Flashcards
What does prevalence measure?
new + existing cases of disease
What is the formula for prevalence?
(# people w/ disease at a given time/total # people in population at same time) * 100
Why might we not report prevalence as a percentage?
If the frequency of disease is very low. We do not want to report it in percentage unless it’s >1%
What are the 2 types of incidence?
- Cumulative Incidence
- Incidence Rate
What is the formula for cumulative incidence?
(# of people w/ disease in specific period/ # of people at risk of that disease at the start of the time period)
How do we determine the denominator in a cumulative incidence calculation?
by looking at the # of people who are alive on the first day of the time period and do not already have the disease
Proportion of people who develop a health outcome in a specific time is what kind of incidence?
Cumulative incidence
How quickly people are acquiring a health outcome is what kind of incidence?
Incidence rate
What is the formula for incidence rate?
(# people w/ disease in a specific period/total person-time contributed by people at risk of disease)
How do we calculate the denominator for an incidence rate calculation?
person-time is calculated by determining the population at risk at the beginning of the period indicated AND the amount of time each person was at risk during the period of time
Incidence density is another name for what incidence calculation?
Incidence rate
Can we use prevalence to measure mortality?
No, only incidence
What are almost all mortality rates multiplied by?
100,000
What is the formula for all-cause mortality rate?
(# of death in one year/# of persons at risk of dying at midyear) * 100,000
What is the formula for cause-specific mortality?
(# deaths due to specific disease in one year/# persons at risk of dying from the disease at midyear) * 100,000
Why do we use mid-year in mortality calculation?
because population are always changing in size so we are looking for the “average” size of the population
How do we calculate the denominator for crude mortality rates?
(population size on Jan. 1 + population size on Dec. 31 same year) /2
How would we interpret 17.4 opioid deaths per 100,000 person-years in 2017 in Alberta?
The cause-specific mortality rate for opioids in Alberta in 2017 was 17.4 opioid deaths per 100,000 person-years
What does case fatality ratio (CFR) measure?
the short-term mortality from an acute disease
What is the formula for case fatality ratio?
(# w/ disease who die from it in time period/# with disease in specified time period)
What is the formula for maternal mortality ratio?
(# of female deaths from childbirth in year/# of live births in year) * 100,000 live births
What does MMR tell us about a society?
it’s an indicator of gender inequality & the quality of the health care system in a country/place
What is infant mortality an indicator of?
a country’s overall health (socially, politically, and economically); how well can a country care for its most vulnerable group?
What is the formula for infant mortality?
(# of infant deaths before 1st bday in 1 yr/# of live births in same yr) * 1,000 live births
What do we always multiple our infant mortality ration calculation by?
1,000 live births
What drives infant mortality ratio?
- Overall health of a society
- preterm birth rate
- infant infection rate
- Sudden infant death syndrome (SIDS) rate
What can improve maternal/infant outcomes?
- Good maternal preconception health
- female education level
- quality of health care system
- Abstaining from pregnancy till >18
- Increased child spacing between pregnancies
What can create an artificially high CFR?
weak testing/screening for a disease
