title: Relative exposure to controller therapy and asthma exacerbations: a validation study in community pharmacies.
abstract: OBJECTIVE
  "Controllers-to-total asthma drug" ratios computed from claims data identify asthmatics at risk of exacerbations. Direct link of ratios to data obtained from patients, such as control and recent outcomes, would facilitate their interpretation. We studied the relationship between R1 ratio (inhaled corticosteroids (ICS)/total anti-asthma drug ratio) and the Asthma Control Test. Comparisons were also conducted for secondary outcomes (asthma-related hospital contacts, monthly medical contacts, use of oral corticosteroids, and perception of disease burden). Results with R1 ratio were compared with those obtained with a second ratio, "ICS-plus-leukotriene receptor antagonist/total asthma drug" (R2 = ICS + leukotriene receptor antagonist/total anti-asthma drugs).
  
  
  METHODS
  A survey was conducted in community pharmacies. Patients visiting with a prescription of anti-asthma drug and ≥12 months of drug dispensing recorded in the pharmacy were consecutively recruited. Dispensing data were linked to patient-reported outcomes. Asthma control and secondary outcomes were compared for both ratios between low-controller-ratio (R < 50%) and high-controller-ratio groups (R ≥ 50%), after excluding null values.
  
  
  RESULTS
  Of the 919 eligible patients (mean age 37 years, 55% women), 90.2% and 92.4% had non-null values for R1 and R2, respectively. Compared with the low-controller-ratio groups, adjusted risks of being uncontrolled were significantly lower in the high-controller-ratio groups (RR = 0.64, 95%CI [0.54, 0.77] and RR = 0.57, 95%CI [0.47, 0.70], for R1 and R2 ratios, respectively). Likewise, fewer patients with secondary outcomes were observed in the high-controller-ratio groups, for both ratios.
  
  
  CONCLUSIONS
  Asthma was better controlled among patients with high controller ratios, along with fewer asthma-related outcomes, for both R1 and R2 ratios. This confirms the utility of asthma/drug ratios in identifying patients at risk of exacerbations, notably in claims data.
authors.affiliation: Lyon Pharmaco-Epidemiology Unit, UMR 5558 CNRS, Claude Bernard, Lyon 1 University, Lyon, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Laforest
authors.forename: Idlir
authors.initials: I
authors.lastname: Licaj
authors.forename: Gilles
authors.initials: G
authors.lastname: Devouassoux
authors.forename: Gérard
authors.initials: G
authors.lastname: Chatté
authors.forename: Manon
authors.initials: M
authors.lastname: Belhassen
authors.forename: Eric
authors.initials: E
authors.lastname: Van Ganse
authors.forename: Geneviève
authors.initials: G
authors.lastname: Chamba
mesh_terms: D000280:Administration, Inhalation; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D003157:Community Pharmacy Services; D003625:Data Collection; D004359:Drug Therapy, Combination; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D020024:Leukotriene Antagonists / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D055815:Young Adult
chemical_list: D018927:Anti-Asthmatic Agents; D005938:Glucocorticoids; D020024:Leukotriene Antagonists
keywords: asthma therapy; community pharmacy; control; exacerbations; inhaled corticosteroids; pharmacoepidemiology