Severe asthma: epidemiology, burden of illness, and heterogeneity

Patients with severe persistent asthma comprise only 5-10 % of the total asthma population, but account for a large proportion of asthma morbidity and health care expenditures. Among patients with severe asthma, higher costs can be expected in association with not well or poorly controlled asthma.

To summarize the evidence concerning the epidemiology, burden, and heterogeneity of severe asthma.

A literature search was performed to identify citations using the terms "severe asthma" and "epidemiology", "asthma control", "asthma" and "heterogeneity".

Successful management of patients with severe asthma continues to be a major unmet need. One of the barriers to successful management is the heterogeneity of asthma. Asthma is not one disease; it is a disorder that can be subdivided into a number of different phenotypes and endotypes. A revised paradigm for asthma management, that entails categorization of asthma patients via use of "biomarkers", and prescribing targeted therapy, will supplant what has been a "one size fits all" approach to asthma management.

The novel approach to asthma management, in which therapy will be more mechanism-specific based on phenotype/endotype, offers the potential for improved asthma care outcomes - particularly for patients with severe persistent asthma who are not well or poorly controlled.