Epidemiology Chp. 4
Card Set Information
Epidemiology Chp. 4
Measures Health Status
What is the crude birth rate?
Used to project population changes; it is
affected by the number and age composition of women of childbearing age
How do you calculate the crude birth rate?
What is the general fertility rate?
Used for comparisons of fertility among
age, racial, and socioeconomic groups.
How do you calculate the general fertility rate?
How do you calculate the infant mortality rate?
What is the neonatal infant mortality rate?
•Reflects events happening after
birth, such as congenital malformations, prematurity (birth prior to 28 weeks
gestation), Low birth weight (<2500 grams)
•Number of deaths occurring in
infants less than or equal to 28 days old per total number of live births
How do you calculate the neonatal infant mortality rate?
What post neonatal infant mortality rate?
•Reflects environmental events,
control of infectious disease and improvement in nutrition. Relatively stable over time
•Number of deaths in infants age
greater than 28 days but less than 365 days old per total number of live births
How do you calculate the fetal death or mortality rate?
What is the fetal death or mortality rate?
•Used to estimate the risk of death
of the fetus associated with the stages of gestation
•The number of fetal deaths after 20
weeks gestation per 1,000 live births plus fetal deaths
What is maternal fatality rate?
Reflects health care access and socioeconomic factors; it includes maternal deaths resulting from causes associated with pregnancy and puerperium (during and after childbirth).
How do you calculate the maternal fatality rate?
What is the perinatal mortality rate?
•Reflects events that occur during
pregnancy and after birth; it combines mortality during the prenatal and
•The number of deaths to infants
between 28 weeks gestation to 7 days after birth per 1,000 live births plus
How do you calculate the perinatal mortality rate?
What the abortion ratio?
•Compares the number of abortions to the number of live births occurring during the same time period
How do you calculate the abortion ratio?
Median age at death is _____
What is frequency?
Number of males
Number of patients missed appointments
Number of cancer deaths
Number of cases
What is relative frequency?
Frequency/counts relative to something.
What is rate?
a ratio that consists of a numerator and a denominator and in which time forms part of the denominator.
•Contains the following elements:
–unit size of population
–time period during which an event occurs
Give an example of a rate.
What is the caution when using crude rates?
•Use crude rates with caution when
comparing disease frequencies between populations.
•Observed differences in crude rates may
be the result of systematic factors (e.g., sex or age distributions) within the
population rather than true variation in rates.
What are specific rates?
Specific rates refer to a particular subgroup of the population defined in terms of
race, age, sex, or single cause of death or illness
What is a ratio?
•The value obtained by dividing one
quantity by another
•The most general form has no specified
relationship between numerator and denominator.
•Proportions, rates, and percentages are
What is a proportion?
•A measure that states a count relative to
the size of the group.
•A ratio in which the numerator is part of
•May be expressed as a percentage.
List mortality measures.
•Crude death rate
specific death rate
specific death rate
Mortality Ration (SMR)
How do you calculate age specific rate?
How do you calculate the age-sex-race specific rate?
How do you calculate the proportionate mortality rate?
What is the proportional mortality ratio?
How do you calculate the Standardized Mortality Ratio (SMR)?
How do you interpret SMR?
•If the observed and expected numbers are
the same, the SMR would be 1.0, indicating that observed
mortality is not unusual.
•An SMR of 2.0 means that the death rate in the
study population is two times greater than expected.
What are measures of morbidity?
•Reported Disease Rate
What is the reported disease rate?
The number of cases of a notifiable
disease reported during a specified period of time per 100,000 (crude
rate). Age, race, sex specific reported
case rates may be obtained in the same manner as crude death rates.
How do you calculate the hospitalization rate?
What is incidence?
The number of new cases of a disease that
occur in a group during a certain time period.
•Describes the rate of development of a
disease in a group over a certain time period.
What are the three elements of incidence rate?
–Numerator = the number of new cases.
–Denominator = the population at risk.
–Time = the period during which the cases
How do you calculate the incidence rate?
What is incidence density?
An incidence measure used when members of a population or study group are under observation for different lengths of
How do you calculate incidence density for time and years?
What is prevalence?
The number of existing cases of a disease
or health condition in a population at some designated time.
•Provides an indication of the extent of a health problem.
How do you calculate point prevalence?
How do you calculate period prevalence?
What is prevalence used for?
•Describing the burden of a health problem
in a population.
•Estimating the frequency of an exposure.
•Determining allocation of health
resources such as facilities and personnel.
what is the interrelationship between prevalence and incidence rate?
•If duration of disease is short and
incidence is high, prevalence becomes similar to incidence.
•Short duration--cases recover rapidly or
•Example: common cold
•If duration of disease is long and
incidence is low, prevalence increases greatly relative to incidence.
•Example: many chronic diseases
What are epidemic curves?
Plotting of the frequency of incident cases over time