Ch. 4 Mortality Flashcards
T or F: Mortality rates can serve as a measure of disease severity and can help us to determine whether a treatment for disease is becoming more or less effective over time.
True
How do we calculate the annual mortality rate for a specific year.
Annual mortality rate for all causes (per 1,000 population)=
(Total #of deaths from all causes in 1 yr. / #of persons in the population at midyear) X 1,000
How do you calculate the morality rate? For a specific population?
Mortality = (# of deaths from all the causes in 1 yr. from the disease of a specific group/ # of people in the population of the specific group)
*such as when we place a restriction to identify the targeted group it becomes a specific rate that must be applied to both the numerator and the denominator.
What is the difference between the mortality rate and the case-fatality rate?
The difference between mortality rate is that it is a measure of the population who is at risk of dying from the disease and includes both who have the disease and those who do not have the disease. While, case-fatality rate is the percentage of people who are diagnosed as having a certain disease and die within a certain time period after being diagnosed.
What is the Formula for Case-Fatality?
Case-Fatality Rate %= (# of individuals dying during a specified period of time after disease diagnosis/ # of individuals with the specified disease) X100
*Can be used to measure the benefits of a new therapy as the case-fatality rate will decline; and thus is a measure of the severity of the disease.
What is proportionate mortality? How is it calculated?
Proportionate mortality is the mortality of a specific disease in a yr; though observed changes can be a result of other diseases rather than a specific disease.
Proportionate Mortality %= (#of deaths from a specific disease in a yr/ total deaths in a yr) X100
How is Years of potential life calculated?
1) For each cause, each decreased persons age is subtracted from a predetermined age of death. (U.S. age 65)
2) The “ Years of potential life lost” for each individual are then added together to yield a YPLL for a specific disease.
How can YPLL “Years of Potential Life Lost:” assist in public health functions?
1) Establishing research and resource priorities.
2) Surveillance of Temporal trends in premature moralities.
3) Evaluating the effectiveness of program interventions.
Under what conditions is the mortality rate a good indication of the risk of the disease?
1) When the case-fatality rate is high
2) When the duration of the disease is short.
An increase in the prevalence of a disease can be the result of what 2 possibilities?
1) Reports of the disease reflect the true increase in the incidence of the disease that result from the increase in the prevalence of the risk factors for the disease.
2) An apparent increase report incidence is only an increase in apparent incidence, due to the our ability to identity the disease more frequently.
*To tester ability to identify the disease, the incidence would more than double and the mortality rate would virtually stay the same.
What problems may arise our to the mortality data?
1) Mortality Data is classified by underlining cause of death; coded by the (ICD) International Classification of disease.
2) Excludes other info such as immediate cause of death
3) Changes in definition of the disease or classifications of the regulations and coding categories effect the trends in mortality and effect the number of cases reported.
True or False: The single most important predictor of mortality is age where the use of mortality data is used to compare two or more populations.
True.
What are the 2 ways in which we can deal with the difference in age when comparing two or more populations?
The 2 ways for dealing with the age differential is by using either the direct or indirect age adjustment when comparing the two or more populations.
Direct- uses a hypothesizes standard population in order to eliminate the effects of the any differences in age between the populations.
Indirect- is used the # of deaths for each age-specific stratum are not available and to study the occupationally exposed population.
How do we calculate the age adjusted rates seen in the direct age adjustment approach
We use a hypothesizes standard population in order to eliminate the effects of the any differences from each of the populations used, we then derive the expected # of deaths that would have occurred. We can then calculate the total # of deaths expected had the age specific rates of the later period been applied. Next, we divide the 2 total expected #’s of deaths by the standard population calculating the the mortality rate.
How do you calculate the standard mortality rate (SMR) for the indirect adjustment approach?
(SMR)= Observed # of deaths per yr. / Expected # of deaths per yr.
