Prevalence, Incidence, & Death

Question 1

What does prevalence measure?

Answer 1

new + existing cases of disease

Question 2

What is the formula for prevalence?

Answer 2

(# people w/ disease at a given time/total # people in population at same time) * 100

Question 3

Why might we not report prevalence as a percentage?

Answer 3

If the frequency of disease is very low. We do not want to report it in percentage unless it’s >1%

Question 4

What are the 2 types of incidence?

Answer 4

1. Cumulative Incidence
2. Incidence Rate

Question 5

What is the formula for cumulative incidence?

Answer 5

(# of people w/ disease in specific period/ # of people at risk of that disease at the start of the time period)

Question 6

How do we determine the denominator in a cumulative incidence calculation?

Answer 6

by looking at the # of people who are alive on the first day of the time period and do not already have the disease

Question 7

Proportion of people who develop a health outcome in a specific time is what kind of incidence?

Answer 7

Cumulative incidence

Question 8

How quickly people are acquiring a health outcome is what kind of incidence?

Answer 8

Incidence rate

Question 9

What is the formula for incidence rate?

Answer 9

(# people w/ disease in a specific period/total person-time contributed by people at risk of disease)

Question 10

How do we calculate the denominator for an incidence rate calculation?

Answer 10

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

Question 11

Incidence density is another name for what incidence calculation?

Answer 11

Incidence rate

Question 12

Can we use prevalence to measure mortality?

Answer 12

No, only incidence

Question 13

What are almost all mortality rates multiplied by?

Answer 13

100,000

Question 14

What is the formula for all-cause mortality rate?

Answer 14

(# of death in one year/# of persons at risk of dying at midyear) * 100,000

Question 15

What is the formula for cause-specific mortality?

Answer 15

(# deaths due to specific disease in one year/# persons at risk of dying from the disease at midyear) * 100,000

Question 16

Why do we use mid-year in mortality calculation?

Answer 16

because population are always changing in size so we are looking for the “average” size of the population

Question 17

How do we calculate the denominator for crude mortality rates?

Answer 17

(population size on Jan. 1 + population size on Dec. 31 same year) /2

Question 18

How would we interpret 17.4 opioid deaths per 100,000 person-years in 2017 in Alberta?

Answer 18

The cause-specific mortality rate for opioids in Alberta in 2017 was 17.4 opioid deaths per 100,000 person-years

Question 19

What does case fatality ratio (CFR) measure?

Answer 19

the short-term mortality from an acute disease

Question 20

What is the formula for case fatality ratio?

Answer 20

(# w/ disease who die from it in time period/# with disease in specified time period)

Question 21

What is the formula for maternal mortality ratio?

Answer 21

(# of female deaths from childbirth in year/# of live births in year) * 100,000 live births

Question 22

What does MMR tell us about a society?

Answer 22

it’s an indicator of gender inequality & the quality of the health care system in a country/place

Question 23

What is infant mortality an indicator of?

Answer 23

a country’s overall health (socially, politically, and economically); how well can a country care for its most vulnerable group?

Question 24

What is the formula for infant mortality?

Answer 24

(# of infant deaths before 1st bday in 1 yr/# of live births in same yr) * 1,000 live births

Question 25

What do we always multiple our infant mortality ration calculation by?

Answer 25

1,000 live births

Question 26

What drives infant mortality ratio?

Answer 26

1. Overall health of a society
2. preterm birth rate
3. infant infection rate
4. Sudden infant death syndrome (SIDS) rate

Question 27

What can improve maternal/infant outcomes?

Answer 27

• Good maternal preconception health
• female education level
• quality of health care system
• Abstaining from pregnancy till >18
• Increased child spacing between pregnancies

Question 28

What can create an artificially high CFR?

Answer 28

weak testing/screening for a disease