A mortality rate is the amount of deaths in a given population during a given period of time. The rate is commonly expressed in deaths out of 100 or 1000 individuals. For instance, if in a town of 10,000 inhabitants, 10 people die of the flu, the flu mortality rate would be one in 1000. Mortality rates can be based on simply how many die of any cause in a population, or can be used to describe the death rate of a certain illness or condition.
Mortality rates have many uses, but are often utilized to describe the increase or decrease in a cause of death over a lengthy time period. For instance, the Center for Disease Control (CDC) used mortality rates to show that the mortality rate for car-accident deaths in the United States dropped from almost 25 per 100,000 to nearly 15 per 100,000 between 1979-2006, while during the same period poisoning deaths rose from five to 15 per 100,000. Looking at the mortality rates over time can help health officials understand where to focus prevention and safety efforts, and indicate possible trends in death due to factors affecting the measured population.
In disease treatment, a mortality rate may be used to explain the likelihood of survival or death. This information can help patients decide what treatment will give them the best chance of survival. Additionally, if the mortality rate of a treatment is extremely high, patients may decide it is too dangerous or not worth the risk or pain of the procedure.
The mortality rate of infants and children is often used as a factor in determining the health status of a country. A high infant mortality rate indicates poor prenatal and obstetric care, and is often found in conjunction with very poor nations or areas. In the United States, infant mortality rates are often broken down by ethnicity or economic bracket, to highlight areas where better care is required.
A mortality rate may also be expressed as a mortality table, also called a life table. Using a generalized table broken down by age, a mortality table shows the mortality rate and probability of death each year. By looking at a life table, a healthy person can determine the likelihood that they will die before their next birthday. Life tables are highly generalized and do not include individual factors that may increase or decrease chances of death, such as whether the person smokes, where they live, and if they have a healthy diet or pre-consisting medical conditions. At best, mortality tables should be looked at as a rough average of likely lifespan.