Prevalencë

Prevalencë is a measure used in epidemiology to describe how widespread a disease or condition is within a defined population. Although commonly spelled prevalence in English, prevalencë appears as a variant in some languages and transliterations. It denotes the proportion of individuals who have the condition at a given time (point prevalencë) or over a defined period (period prevalencë). It contrasts with incidence, the rate at which new cases occur.

Calculation and types: Point prevalencë = number of existing cases at a specific time divided by the total population at that time. Period prevalencë covers cases during a time interval divided by the average population during that interval. Crude prevalencë is the raw proportion; age-standardized prevalencë adjusts for age distribution to enable fair comparisons across populations.

Data sources and interpretation: Estimates derive from health surveys, electronic health records, disease registries, or census data. Higher prevalencë can result from high incidence, long disease duration, or improved survival; lower prevalencë may reflect rapid recovery or high mortality. Changes in diagnostic criteria or screening practices can also shift prevalencë independently of actual disease burden.

Limitations and applications: Biases include underdiagnosis, misclassification, incomplete case capture, and inconsistent definitions. Prevalencë data inform planning of health services, monitoring of population health, and evaluation of interventions.

See also: incidence, point prevalencë, period prevalencë, age-standardized prevalencë.