Epi Chp 4

Question 0

Annual mortality rate for all causes formula

Answer 0

Per 100,000 in the population

Number of people in the population at midyear

Multiply answer by 1000

(note that because the population changes over time, the number of persons in the population at midyear is generally used as an approximation)

Question 1

What can mortality rates help us understand

Answer 1

Mortality rates can serve as measures of disease severity

And can help us to determine whether the treatment for disease has become more effective overtime

Mortality rate may serve as surrogates for incident rates when the disease being studied is a severe and lethal one

Question 2

Important principle

For any mortality rate to make sense what has to occur

Answer 2

Anyone in the group represented by the denominator must have the potential to enter the group represented by the numerator

Question 3

And your mortality rates from all causes for a specific age group formula

Answer 3

Number of people in the population in that same age group at midyear

All multiplied by 1000

(remember any restriction must be applied to both the numerator and the denominator)

Question 4

When a restriction is placed on the numerator and denominator, for example age, what is it called (what is its name)

Answer 4

Specific rate

I.e. age specific mortality rate

Question 5

Formula for calculating annual mortality rate from lung cancer (per 1000 population)

Answer 5

Number of deaths from lung cancer in one year divided by number of persons in the population here all times 1000

# death lung cancer in a year
----------------------------------- x 1000
# people in population mid year

Question 6

Formula for determining case-fatality

Answer 6

# pepole dying during time period after onset or dx
----------------------------------- x 100
# people with disease

In other words what percentage of people who have a certain disease died within a certain time after the disease is diagnosed

Question 7

What is the difference between case fatality and mortality rate?

Answer 7

In mortality rate, the denominator represents the entire population at risk of dying from the disease including those who have the disease and those who do not have the disease but who may be at risk for developing the disease

Case fatality-however, the denominator is limited to those who already have the disease
(case fatality is a measure of the severity of the disease)
** note that case fatality is not a rate but a percentage (of those with the disease)***

Question 8

Case fatality is a measure of the severity of disease how can case fatality information be used ?

Answer 8

It can be used to measure any benefits of the new therapy as therapies improve case fatality would be expected to decline.

Question 9

Define proportionate mortality and the formula?

Answer 9

deaths from specific dz in 2010
————————————-X 100
Total deaths in area in 2010

In other words of all the deaths in a population what proportion was caused by a specific disease

Question 10

Define years of potential life lost

Answer 10

YPLL is a measure premature of mortality or early death

In the United States this predetermined standard age is usually 75 years old

Question 11

Why look at mortality ?

Answer 11

Mortality is a clear index of the severity of disease from both clinical and public health standpoint, but mortality can also be used as index of the risk of disease

In general, mortality data is easier to obtain then incidents data for a given disease, and it therefore may be more feasible to use mortality data as an index of incidence

However when a disease is mild and not fatal, mortality is not a good index of incidence

Question 12

Mortality rate is a good reflection of the incidence rate under what two conditions?

Answer 12

First- when the case-fatality rate is high (as in untreated rabies)

Second- when the duration of disease (survival) is short

Under these conditions mortality is a good measure incidence and the same measure of the risk of disease

Question 13

Problems with mortality data included?

Answer 13

Most information about deaths comes from death certificates: and are coded according to the underlying cause.

The underlying cause of death is defined as the disease or injury which initiated the train of morbid events leading directly or indirectly did death or circumstances of the accident or violence which produced the fatal injury

Countries and regions very greatly in the quality of data provided on the death certificates

Any codes used in the ICD-9 system may not automatically translate to the new version ICD 10

Question 14

Whenever we see a time trend of an increase or decrease in mortality, the first question we must ask is?

Answer 14

Is it real?

Question 15

What is the purpose of direct age adjustment?

Answer 15

If the Agr composition of the population were the same, would there be any differences in mortality?

Direct age adjustment-the standard population is used in order to eliminate the effects of any differences in age between two or more populations being compared

Question 16

Define Indirect Age adjustment (standardized mortality ratio)

Answer 16

Indirect age adjustment is often used for numbers of deaths for each age specific stratum are not available.

It is also used to study mortality in an occupational expose population