Prevalence and Incidence of Chiari Malformation

Chiari Malformation: Rare Disease

Chiari Malformation is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Chiari Malformation, or a subtype of Chiari Malformation, affects less than 200,000 people in the US population.

Ophanet, who are a consortium of European partners, currently defines a condition rare when if affects 1 person per 2,000. They list Chiari Malformation as a "rare disease". More information about Chiari Malformation is available from Orphanet

About prevalence and incidence statistics:

The term 'prevalence' of Chiari Malformation usually refers to the estimated population of people who are managing Chiari Malformation at any given time. The term 'incidence' of Chiari Malformation refers to the annual diagnosis rate, or the number of new cases of Chiari Malformation diagnosed each year. Hence, these two statistics types can differ: a short-lived disease like flu can have high annual incidence but low prevalence, but a life-long disease like diabetes has a low annual incidence but high prevalence. For more information see about prevalence and incidence statistics.