MORBIDITY

In medicine, epidemiology and actuarial science, the term morbidity can refer to

• the state of being diseased (from Latin morbidus: sick, unhealthy),
• the degree or severity of a disease,
• the prevalence of a disease: the total number of cases in a particular population at a particular point in time,
• the incidence of a disease: the number of new cases in a particular population during a particular time interval.

In actuarial science the term can also refer to disability irrespective of cause (e.g., disability caused by accidents).

Accordingly, the term morbidity rate can refer either to the incidence rate or to the prevalence rate of a disease. Compare with mortality rate, the number of people dying from a particular disease during a given time interval, divided by the total number of people in the population. Morbidity is often what is measured by ICU scoring systems.