Table 1. Evolution of the definition of “severe” asthma
Organisation, yearTermDefinition
ERS, 1999Difficult asthmaAsthma remaining uncontrolled despite high-dose inhaled glucocorticosteroids with or without systemic glucocorticosteroids
Uncontrolled asthmaPersistent asthma symptoms or recurrent exacerbations
ATS, 2000Severe refractory asthmaAccording to an ERS Task Force including criteria that specifies asthma control
WHO, 2010Addition of responsiveness to treatment and future risk as a marker for asthma control
IMI, 2011Poorly controlled asthmaAlgorithm to distinguish difficult-to-control asthma from severe refractory asthma
ATS/ERS, 2013Latest recommendations on the identification, evaluation and treatment of patients with severe refractory asthma
  • ERS: European Respiratory Society; ATS: American Thoracic Society; WHO: World Health Organization; IMI: Innovative Medicines Initiative.