Epidemiology 4-occurance of dieases, mortality and other measures of disease impact

Question 1

How does mortality rate help preventive measures ?

How long can mortality rate be calculated ?

Is the period selected matter ?

Answer 1

Mortality

• Mortality rates can serve as measures of disease severity and can help us to determine whether the treatment for a disease has become more effective over time.
• Mortality can be calculated over 1 year, 5 years, or longer.
• The period selected is arbitrary

Question 2

What three aspects does mortality cover ?

Answer 2

Mortality

–index of the severity of a disease

–index of the risk of a disease

–disease is mild and not fatal, mortality rate is not a good index of incidence

Question 3

What is mortality a good reflection of ?

What does mortality depend on ?

Answer 3

Mortality is a good reflection of the incidence rate

–Case-fatality rate is high

–Survival is short

•Mortality-depends of the risk factors associated to disease & detection programs

Question 4

Formula for annual mortality rate for all causes? What is the number at midyear ?

Answer 4

Question 5

What is the annual mortality rate from lung cancer? Examples.

Answer 5

Mortality rate is alwasy divided by all the deaths on that topic midyear!

Question 6

.What is the formula for case fatality rate ?

Answer 6

Case-fatality rate (percent)=

No. of individuals dying during a specified period of time after disease onset or diagnosis

No. of individuals with the specified disease

•The percentage of people diagnosed as having a certain disease die within a certain time after diagnosis.

Question 7

.Difference between mortality rate & case-fatality rate

Answer 7

• Mortality-the denominator includes the entire population at risk of dying from the disease (who have the disease + who do not have the disease).
• Case-fatality rate-the denominator is limited to those who have the disease.

–Measure of severity

Question 8

.What is proportionate mortality ? What is it not?

Answer 8

Proportionate mortality

• Proportionate mortality-is not a rate.
• Proportionate mortality from diabetes mellitus in the US in 1999 (percent)=

of deaths from diabetes mellitus in the US in 1999/ Total deaths in the US in 1999 x 100

•Of all deaths, what proportion was caused by diabetes mellitus.

Question 9

Proportionate mortality example

Answer 9

Question 10

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Question 11

Difference between mortality rate & case-fatality rate, do it by hand

Answer 11