CH. 5 - mortality

Cause-Specific Death Rate formula

( # of deaths due to specific cause ) ----------------------------------------------------------------------------------------- ( total # or pop. @ midpoint • time must be specified

Case Fatality Rate Formula

(# of causes-specific deaths among the incident cases) ----------------------------------------------------------------------------------------- (# of incident cases) X 10^n

Crude Mortality Rate

(# of deaths in the @ a specific time) ----------------------------------------------------------------------------------------- (Total Population @ specific time) X 10^n

Survival Rate Formula

(# of newly diagnosed patients with a given disease -- the # of deaths observed among patients in a specified time period) ----------------------------------------------------------------------------------------- (# of newly diagnosed patients with the disease in the same time period) X 10^n

Proportionate Mortality Formula

(#of deaths due to a particular cause) ----------------------------------------------------------------------------------------- (total deaths from all causes) X 100

Proportionate Mortality

*Describes the proportion of deaths in a specified population over a period of time attributable to different causes* Expressed as a percentage (%)

Case Fatality Rate

*Proportion of persons with a particular condition (case) who die from that condition* • must have illness • must die of illness ( & no other cause)

Crude Death (mortality) Rate

AKA: Annual Death Rate, Mortality Rate Usually done at midyear (6/30) due to people moving Anyone in the denominator group must have the *potential to enter the group represented by the numerator*

Cause-Specific Death Rate

Mortality rate from a specified cause for a population. The numerator is the number of deaths attributed to a specified cause. The denominator remains the size of the population at the midpoint of the time period.

Case Fatality Rate

Proportion of persons with a particular condition (case) who die from that condition

a total of 2,123, 323 deaths were recorded in the US in 1987. the mid-year pop. was estimated to be 243, 401, 000. approx. 13,468 died of HIV cause-specific death rate:

cause-specific death rate: = (# of deaths due to a specific cause ) / (# of pop. @ midpoint) X 10^n = ( 13,486 ) / (243, 401, 000 ) X 10^5 = 5.5 per 100,000

a total of 2,123, 323 deaths were recorded in the US in 1987. the mid-year pop. was estimated to be 243, 401, 000. calculate crude death (mortality) rate:

crude death (mortality) rate: = ( # of deaths @ a specific time) / ( total population @ specific time ) X 10^n = ( 2, 123, 323 ) / ( 243, 401, 000 ) X 10^5 = 8.75 per 100,000

population of 100,000 people of whom 20 are sick w/ disease X and in one year, 18 of the 20 die from disease X calculate mortality rate: calculate case- fatality rate: whats does this tell us?

mortality rate: = ( # of deaths @ a specific time) / ( total population @ specific time ) X 10^n = (18 ) / (100,000) = 0.00018 X 100 = 0.018% cause-specific death rate: = ( # of cause-specific deaths among the incident cases ) / (# of incident cases ) X 10^n = ( 18 ) / ( 20 ) = 0.9 X 100 = 90% THIS TELLS US.. disease is rare (0.018%) , but if you get it the chances of dying with/from its are about 90%

why study mortality?

• *measure of disease severity* • determines if treatment for a disease becomes more effective over time • serves as a substitute for incidence & prevalence rate when a disease is deadly

Measures of Mortality:

• Crude Death Rate (10^n) • Cause-Specific Death Rate (10^n) • Age-Specific Mortality Rate • Proportional Mortality (100)(%) • Neonatal Mortality Rate • Infant Mortality Rate • Maternal Mortality Rate

Mortality Rates

• Good reflection of incidence (severity) • If CFR is high • Duration of disease (survival) is short

Survival Rate

• Measure of *prognosis* • Measures *probability of surviving a specified period of time* • Expressed as a percent