title: Inhaled corticosteroids for asthma: impact of practice level device switching on asthma control.
abstract: BACKGROUND
  As more inhaled corticosteroid (ICS) devices become available, there may be pressure for health-care providers to switch patients with asthma to cheaper inhaler devices. Our objective was to evaluate impact on asthma control of inhaler device switching without an accompanying consultation in general practice.
  
  
  METHODS
  This 2-year retrospective matched cohort study used the UK General Practice Research Database to identify practices where ICS devices were changed without a consultation for > or =5 patients within 3 months. Patients 6-65 years of age from these practices whose ICS device was switched were individually matched with patients using the same ICS device who were not switched. Asthma control over 12 months after the switch was assessed using a composite measure including short-acting beta-agonist and oral corticosteroid use, hospitalizations, and subsequent changes to therapy.
  
  
  RESULTS
  A total of 824 patients from 55 practices had a device switch and could be matched. Over half (53%) of device switches were from dry powder to metered-dose inhalers. Fewer patients in switched than matched cohort experienced successful treatment based on the composite measure (20% vs. 34%) and more experienced unsuccessful treatment (51% vs. 38%). After adjusting for possible baseline confounding factors, the odds ratio for treatment success in the switched cohort compared with controls was 0.29 (95% confidence interval [CI], 0.19 to 0.44; p < 0.001) and for unsuccessful treatment was 1.92 (95% CI, 1.47 to 2.56; p < 0.001).
  
  
  CONCLUSIONS
  Switching ICS devices without a consultation was associated with worsened asthma control and is therefore inadvisable.
authors.affiliation: Department of General Practice and Primary Care, University of Aberdeen, Foresterhill Health Centre, Westburn Road, Aberdeen, UK. drmike.thomas@btinternet.com
authors.forename: Mike
authors.initials: M
authors.lastname: Thomas
authors.forename: David
authors.initials: D
authors.lastname: Price
authors.forename: Henry
authors.initials: H
authors.lastname: Chrystyn
authors.forename: Andrew
authors.initials: A
authors.lastname: Lloyd
authors.forename: Angela E
authors.initials: AE
authors.lastname: Williams
authors.forename: Julie
authors.initials: J
authors.lastname: von Ziegenweidt
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage* / Q000191:economics / Q000627:therapeutic use*; D000328:Adult; D001249:Asthma / Q000188:drug therapy*; D016022:Case-Control Studies; D015331:Cohort Studies; D003362:Cost-Benefit Analysis; D005194:Family Practice; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D012017:Referral and Consultation; D012044:Regression Analysis; D012189:Retrospective Studies; D012923:Social Class; D016896:Treatment Outcome; D006113:United Kingdom; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones