Measures of Morbidity and Mortality

Question 1

Define prevalence

Answer 1

The number of existing cases of a disease or health condition in a population at some designated time.

~ Burden of a health problem in a population

Question 2

Equation for point prevalence

Answer 2

(# of persons ill) / (total number in the group)

Question 3

Period prevalence equation

Answer 3

(# of persons ill)/(average total population)

Question 4

Definition of incidence

Answer 4

The number of new cases of a disease or health condition that occur in a group during a certain time period.

Question 5

What is cumulative Incidence?

Answer 5

1. The rate of development of a disease in a group over a certain time period
2. Risk of developing a disease

Question 6

equation for cumulative incidence

Answer 6

(# of new cases of a disease)/ (# of persons who are at risk of developing the disease at the beginning of the time period)

Question 7

Incidence density

Answer 7

An incidence measure used when members of a population or study group are under observation for different lengths of time.

Question 8

Equation for incidence density

Answer 8

(# of new cases of a disease)/ (sum of length of time at risk for each individual in the population)

Question 9

If duration of disease is short, what happens to prevalence?

Answer 9

Prevalence becomes similar to incidence

Question 10

If cases recover rapidly or are fatal what will happen to the prevalence of the population?

Answer 10

Cases will not accumulate and the prevalence is a lot shorter.
Examples are common cold and pancreatic cancer.

Question 11

If the duration of disease is long, even when the incidence is low what happens to the number of cases?

Answer 11

It accumulates relative to incidence

Question 12

calculation of crude mortality rate

Answer 12

(# of deaths in a specified population in a given time period) /( average total population during the midpoint of the year)

Question 13

specific rates

Answer 13

refers to a particular subgroup of the population defined in terms of race, age, sex, or single cause of death or illness.

Question 14

equation for cause specific rate

Answer 14

(# of deaths due to a disease)/(total population at midpoint of time period)

Question 15

Case fatality rate equation

Answer 15

(# of deaths from a disease in a given time period)/( Number of diagnosed cases of that disease during the same period)

Question 16

Equation for proportional mortality ratio

Answer 16

(mortality due to a specific cause)/(Mortality due to all causes during time period).

Question 17

When can direct method be used?

Answer 17

1. age specific death rates in a population to be standardized are known and
2. suitable standard population is available.

Question 18

When can indirect method be used?

Answer 18

1. age specific death rates of the population for standardization are unknown or unstable. For example if rates are based on a small population.

Question 19

How can we find age specific death rates of a population in indirect method?

Answer 19

The standardized mortality ratio (SMR) is used

Question 20

Age specific rate is calculated by

Answer 20

(# of deaths among those age)/( total number of persons who are in that age range)

Question 21

difference between crude and adjested rates

Answer 21

crude rates might give rise to misleading conclusions if they are used to compare health status between populations. They may be a result of systematic factors (age or gender).

Question 22

Artificial rate

Answer 22

Does not represent actual health status…it’s the adjusted rate.

Question 23

Standardized Mortality ratio is calculated by

Answer 23

observed deaths/expected deaths

Question 24

Indirect age adjustment is calculated by

Answer 24

SMR X overall death rate in the standard population (standard population crude death rate).