Morbidity + Mortality Measurements Flashcards
How are mortality data used?
- to explain trends and differences in overall mortality
- indicate priorities for health actions/allocation of resources
- provides data for use in designing interventions
- in assessments an dmonitoring of public health programs - are public health programs working?
- Provide clues in epidemiological investigations
Limitations to capturing mortality data?
We do not have a great system for parsing out actual cause of death
* surveillance
* death certificates
* innacurate reporting due to stigma
* compounded causes of death
Describe the history of methods of capturing mortality data
- Bills of mortality (london annual register of death 1665) = unable to accurately capture death (didnt capture those who were not buried), did not capture dissenters, catholics, criminals, etc
- in 1836 was replaced with the modern death registration system by W. farr (father of modern epidemiology)
- Now WHO manages this: ICD-10 (still limited to 1 absolute cause of death
Mortality Rate =
deaths occurring during a given time period/size of the population in which they occurred (x10^10)
Case Fatality Rate (CFR) =
What is it usually used for?
What type of diseases is it normally used for?
Number of deaths from a specific disease during a given time/ number of acses of that dieseas during the same time (x100)
CFR usually used to determine the ‘killing power’ of a disease… how deadly does it appear to be?
Primarily used with highly infectious diseases
Proportionate Mortality Rate (PMR) =
What is PMR used to decide?
Number of deahts from a specific cause during a given time / total number of deahts from all causes in the same time (x100)
What is killing people the most? (Where to allocate resources)
The simplest measure of estimating the burden of a disease in the community
Cause Specific Mortality Rate (CSMR) =
Number of deaths from a specific cause during given time / total population (x100)
Crude Mortality Rate (Crude Death Rate) =
All deaths during a calendar year / the total midyear population (x1000)
The crude death rate gives an estimate as to the rate at which people seem to be dying
Infant Mortality Rate (IMR) =
Number of infant deaths less than 1 year of age / Total number of live births during the same year (x1000)
usually expressed per 1000 live births
a death doesnt cound if no birth certificate…
Neonatal Mortality Rate =
Number of neonatal deaths (under 28 days) / total number of live births during the same year (x1000)
measures risk of dying among infants under 28 days
the most vulnerable point in human life
Post-neonatal mortality rate =
Number of deaths 29-365 days / Total live births during the same year (x1000)
measures risk of dying among older infants (28 days to 12 months)
Causes of neonatal deaths developed vs developing countries
Developed: LBW, Congenital anomalies, maternal complications
Developing: LBW, Trauma, tetanus, pneumonia
Causes of Postneonatal deaths in developing vs developed countries
developed: Congenital abmomilies, injuries, infection
Developing: infection, malnutrition, injury
Maternal Mortality
MMR =
Maternal Death = the death of a woman while pregnant or within 42 days of termination of a pregnancy (irrespective of the duration) from any cause related to or aggravated by the pregnancy or its management (not from accidental causes)
MMR = # of female deaths from pregnancy, childbirth, puerperal causes in a year / # of life births in that same year (x1000)
*usually reflects maternal health in a particular region
MMR is one of the best indicators of overall health of a population: reflects quality of maternal health care and overall other factors such as access to adequate nutrition, gender discrimintation, and power
How does the WHO define the periods of fetal death?
Early = under 20 weeks
Intermediate = 20-27 weeks
Late = 27 weeks and over
Late Fetal Death Rate =
number of fetal deaths (28 + weeks) during 1 year / number of live births that year
usually expressed per 1,000
Still Birth Rate =
Number of fetal deaths (28+ weeks of gestation) during 1year / (# total births)
usually expressed per 1000
Child Death Rate (or under 5 mortality rate)
Defined as the numbers of death at age 1-4 years in a given year per 1000 children in that age group at the midpoint of the year (therefore excludes the IMR as infants are not included)
A child survival rate per 1000 births ca be simply calculated by subtracting the U5 mortality rate from 1000 and dividing by 10
Shows the percentage of those who survive to age 5 (a milestone measure of population health)
Tells us child health status & conditions related to malnutrition, injuries, infectious diseases
What three types of mortality measures when combined are good indicators of social inequality?
Infant & Child mortality coupled w data on maternal health
Developed vs developing countries rates of neonatal mortality to post-neonatal mortality
Developed: Ratio NM:PNM = 3-4:1
Developing: Ratio NM:PNM = 1: 1-2
Still Birth Rate =
Number of deaths after the 28 weeks of pregnancy occuring during one year per 1000 total births (still and live births)
Perinatal Mortality Rate =
Typical causes?
(# still births + deaths <7days)/total births (x1000)
Perinatal = death of a fetus/baby between 28 weeks of gestation and within the first 7 days after birth
- it is a more specific measure and description of that vulnerable time
Typical causes: infection, hypertension, and intrapartum asphyxia
- typically termed ‘stillbirth’
Essential because it measures the risk of dying between 28 weeks gestation and first week of life = indicates the status of delivery and …
Why is it misleading to describe health solely in terms of mortality?
- Because mortality indicators do not reveal the true burden of ill health in a community
- ex: mental illness, infertility, rheumatoid arthrities (invisible illness, those grounded in health inequities, etc)
- Therefore we use those earlier morbidity measures to describe the health status of a population (incidence, prevalence, notification rates, attendance rate at outpatient clinic, admission, readmission, and discharge rates, hospital durations, school absences, sick days from work)
Types of Morbidity Rates:
- Incidence
- cumulative incidence
- attack rate - Prevalence
- point prevalence
- period prevalence
