title: Persistence of asthma medication use in preschool children.
abstract: OBJECTIVE
  In young children with asthmatic symptoms diagnostic difficulties lead to use of trials of asthma medication as a diagnostic tool. Our aim is to quantify the persistent use of asthma medication, initiated in the first year of life and identify determinants of this persistent use.
  
  
  METHODS
  We identified 165 children within the PIAMA (Prevention and Incidence of Asthma and Mite Allergy) birth cohort who used asthma medication before the age of one. Persistent use was investigated during three years after the first prescription. A Cox regression analysis was performed to identify factors associated with persistent use.
  
  
  RESULTS
  A total of 58.8% of children continued using asthma medication after the first prescription and 10.3% continued during three years. Children with doctor-diagnosed asthma (Hazard ratio of discontinuation (HR)=0.64, 95% CI: 0.45-0.91) or prescribed inhaled corticosteroids in the first year of life (HR of discontinuation=0.59, 95% CI: 0.40-0.86) were 1.6-1.7 times more likely to continue using asthma medication.
  
  
  CONCLUSIONS
  Persistence of asthma medication, prescribed in the first year of life is very low and is positively associated with doctor-diagnosed asthma and use of inhaled corticosteroids. Characterizing persistent users of asthma medication is important to understand prescribing of asthma medication in this age group.
authors.affiliation: Division of Pharmacoepidemiology and Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands.
authors.forename: Mira G
authors.initials: MG
authors.lastname: Zuidgeest
authors.forename: Henriëtte A
authors.initials: HA
authors.lastname: Smit
authors.forename: Madelon
authors.initials: M
authors.lastname: Bracke
authors.forename: Alet H
authors.initials: AH
authors.lastname: Wijga
authors.forename: Bert
authors.initials: B
authors.lastname: Brunekreef
authors.forename: Maarten O
authors.initials: MO
authors.lastname: Hoekstra
authors.forename: Jorrit
authors.initials: J
authors.lastname: Gerritsen
authors.forename: Marjan
authors.initials: M
authors.lastname: Kerkhof
authors.forename: Johan C
authors.initials: JC
authors.lastname: de Jongste
authors.forename: Hubert G
authors.initials: HG
authors.lastname: Leufkens
mesh_terms: D000280:Administration, Inhalation; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy; D002675:Child, Preschool; D004334:Drug Administration Schedule; D004522:Educational Status; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use*; D006801:Humans; D007223:Infant; D008297:Male; D010290:Parents; D016016:Proportional Hazards Models; D013997:Time Factors
chemical_list: D018927:Anti-Asthmatic Agents; D005938:Glucocorticoids