Mortality rate

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"Mortality" redirects here. For the band Mortality, see Mortality (band).

Image:Death rate world map.PNG Mortality rate is a measure of the number of deaths (in general, or due to a specific cause) in some population, scaled to the size of that population, per unit time. Mortality rate is typically expressed in units of deaths per 1000 individuals per year; thus, a mortality rate of 5.5 in a population of 100,000 would mean 550 deaths per year in the entire population. It is distinct from morbidity rate, which refers to the number of individuals who have contracted a disease during a given time period (the incidence rate) or the number who currently have that disease (the prevalence rate), scaled to the size of the population.

One distinguishes:

The crude death rate, the total number of deaths per 1000 people.
The perinatal mortality rate, the sum of neonatal deaths and fetal deaths (stillbirths) per 1,000 births.
The maternal mortality rate, the number of maternal deaths due to childbearing per 100,000 live births.
The infant mortality rate, the number of deaths of children less than 1 year old per thousand live births.
The standardised mortality rate (SMR) or age-specific mortality rate (ASMR) - This refers to the total number of deaths per 1000 people of a given age (e.g. 16-65 or 65+).

In regard to the success or failure medical treatment or procedures, one would also distinguish:

The early mortality rate, the total number of deaths in the early stages of an ongoing treatment, or in the period immediately following an acute treatment.
The late mortality rate, the total number of deaths in the late stages of an ongoing treatment, or a significant length of time after an acute treatment.

Note that the crude death rate as defined above and applied to a whole population can give a misleading impression. For example, the number of deaths per 1000 people can be higher for developed nations than in less-developed countries, despite standards of health being better in developed countries. This is because developed countries have relatively more older people, who are more likely to die in a given year, so that the overall mortality rate can be higher even if the mortality rate at any given age is lower. A more complete picture of mortality is given by a life table which summarises mortality separately at each age. A life table is necessary to give a good estimate of life expectancy.