title: Severe asthma: epidemiology, burden of illness, and heterogeneity.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  To summarize the evidence concerning the epidemiology, burden, and heterogeneity of severe asthma.
  
  
  METHODS
  A literature search was performed to identify citations using the terms "severe asthma" and "epidemiology", "asthma control", "asthma" and "heterogeneity".
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Respiratory Institute, Department of Allergy and Clinical Immunology, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Lang
mesh_terms: D001249:Asthma / Q000175:diagnosis / Q000191:economics* / Q000453:epidemiology* / Q000628:therapy; D015415:Biomarkers; D017281:Cost of Illness; D019468:Disease Management; D006801:Humans; D017063:Outcome Assessment, Health Care; D010641:Phenotype; D057285:Precision Medicine; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology / Q000208:ethnology
chemical_list: D015415:Biomarkers