title: Comparative outcomes of leukotriene receptor antagonists and long-acting β-agonists as add-on therapy in asthmatic patients: a population-based study.
abstract: BACKGROUND
  Recent evidence suggests that the use of leukotriene receptor antagonists (LTRAs) in addition to inhaled corticosteroids (ICSs) in asthmatic patients provides comparable benefits to the addition of long-acting β-agonists (LABAs) to ICSs.
  
  
  OBJECTIVE
  We sought to compare, in a unified framework, adherence, outcomes, and costs associated with ICS+LTRA versus ICS+LABA as step-up therapies for asthma.
  
  
  METHODS
  Using the administrative databases of British Columbia, Canada (years 1997-2007), we created a propensity score-matched sample of asthmatic patients (12-45 years old) receiving ICS+LTRA therapy versus ICS+LABA therapy after a period of monotherapy with an ICS. We compared the outcomes using 2 analyses: an intention-to-treat (ITT) analysis that followed subjects for a fixed period of 2 years and an uninterrupted treatment analysis that followed subjects for as long as they continuously dispensed their index medications.
  
  
  RESULTS
  The matched cohort consisted of 1032 subjects in each group (mean age at entry, 27.4 years; 52.5% female). Adherence, which was defined as the proportion of days covered, was higher in the ICS+LABA group compared with the ICS+LTRA group. In both the ITT and uninterrupted treatment analyses, use of ICS+LTRA therapy was associated with more asthma-related outpatient visits, asthma-related medication dispensations, and dispensation of reliever medications. Dispensation of oral corticosteroids and rate of asthma exacerbations were higher in the ICS+LTRA group in the uninterrupted treatment analysis but not in the ITT analysis.
  
  
  CONCLUSIONS
  In a real-world clinical setting subjects were more adherent to ICS+LABA therapy than ICS+LTRA therapy. ICS+LABA therapy seems to be more effective than ICS+LTRA therapy in the management of asthma, regardless of adherence.
authors.affiliation: Institute for Heart and Lung Health, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada. msafavi@mail.ubc.ca
authors.forename: Mohsen
authors.initials: M
authors.lastname: Sadatsafavi
authors.forename: Larry
authors.initials: L
authors.lastname: Lynd
authors.forename: Carlo
authors.initials: C
authors.lastname: Marra
authors.forename: Pierrick
authors.initials: P
authors.lastname: Bedouch
authors.forename: Mark
authors.initials: M
authors.lastname: Fitzgerald
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000328:Adult; D001249:Asthma / Q000188:drug therapy*; D006801:Humans; D020024:Leukotriene Antagonists / Q000627:therapeutic use*; D055118:Medication Adherence; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D000318:Adrenergic beta-Agonists; D020024:Leukotriene Antagonists