title: Definitions of asthma exacerbations.
abstract: OBJECTIVE
  During the past decade exacerbations of asthma have increasingly been recognized a as primary outcome parameter in clinical research. However, comparison of results is hampered by the use of different definitions for asthma exacerbations in published reports. The purpose of this review is to describe the consequences of using different definitions and to propose possible solutions.
  
  
  RESULTS
  The use of different definitions of asthma exacerbations not only influences incidence rates, but also affects patient identification and risk assessment. The American Thoracic Society/European Respiratory Society and the World Health Organization independently proposed consensus definitions based on clinical symptoms and management. This needs to be complemented by a prospective definition that may support clinicians in their treatment decisions.
  
  
  CONCLUSIONS
  Currently there is no commonly accepted definition for asthma exacerbations. A prospective definition is desirable. This could be obtained by phenotyping asthma exacerbations based on clinical signs, lung function parameters and possibly other biomarkers.
authors.affiliation: Department of General Practice, Academic Medical Centre - University of Amsterdam, Amsterdam, the Netherlands. r.j.loijmans@amc.uva.nl
authors.forename: Rik J B
authors.initials: RJ
authors.lastname: Loymans
authors.forename: Gerben
authors.initials: G
authors.lastname: Ter Riet
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Sterk
mesh_terms: D001249:Asthma / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*; D015415:Biomarkers / Q000378:metabolism; D002986:Clinical Trials as Topic; D018450:Disease Progression; D006801:Humans; D015994:Incidence; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012720:Severity of Illness Index; D013223:Statistics as Topic
chemical_list: D015415:Biomarkers