Measuring Outcomes Flashcards
Define death rates
Number of deaths/number of people at risk of dying
Define age-specific death rates
Death rate for specific group of population
Define proportionate mortality
Number of deaths from a given cause, per 100 or per 1000 total deaths.
Define infant mortality
Deaths of children aged 1-4 years. This is a basic health indicator.
Which death rate is a basic health indicator?
Infant mortality
Define maternal mortality rate
Risk of mothers dying from causes associated with delivering babies, complication of pregnancy or childbirth.
Define adult mortality rate
Probability of dying between the ages of 15 and 60 years, per 1000.
Define life expectancy
Average number of years an individual of given age is expected to live is current mortality rates continue
Define age-standardised rates
Summary measures of death rate that a population would have if it had a standard age structure.
Define morbidity
Any departure, subjective or objective, from a state of physiological or psychological well being.
What is commonly used to measure morbidity?
Quality adjusted life years and disability adjusted life years.
What are years of potential life lost (PYLL)?
Measure of health expectancy or number of potential years of life lost if they die before a certain age (normally before 65).
PYLL= (total number of deaths from a specific cause in each age group) x (average number of years of life lost as a result of each of these deaths).
What are quality-adjusted life years (QALYs)
Weigh each year of life by the perceived quality of that life from a value of 1 (perfect) down to 0.
What are disability-adjusted life years (DALYs)
Measure of overall disease burden, expressed as the cumulative number of years lost due to ill-health, disability or early death.
DALYs = Years of Life Lost (YLL) + Years Lost to Disability (YLD)
YYL- actual death
YLD- alive but reduced quality of life
What is incidence?
The rate of occurrence of new cases in a given period in a given population.
What are the two ways in which incidence is expressed as and calculated?
Rate = (number of new cases)/ person-time Cumulative incidence (proportion) = (# of new cases during a time period)/ (#of disease-free subjects at the start of follow-up). Values range 0-1
What is prevalence?
Frequency of existing cases in defined population at a give time.
How is prevalence calculated?
(# cases of a disease present in a population)/ (# of persons in a population).
If the incidence is low and the population is stationary, how else can prevalence be calculated?
(Incidence rate) x (average duration of disease)
What is attack rate?
(Number of people affected) / (number of people exposed to each food)
Used for outbreaks that occur over a short period of time (e.g. salmonella outbreak).
What is case fatality?
Deaths within those diagnose by the disease
Case fatality= (number of deaths from diagnosed cases in a given period) / (number of diagnosed cases of the disease in the same period) x 100.
What is the relative risk, or risk ratio?
(Risk in the exposed population) / (risk in the unexposed population) = (Re/Ru)
What is the attributable risk, risk difference?
(Risk difference): risk attributable to the exposure
Difference in risk between exposed and unexposed Re-Ru
How do you calculate the percentage of cases that can be attributed to the exposure?
(Re-Ru)/Re x 100%
