title: Adherence to inhaled corticosteroids: an ancillary study of the Childhood Asthma Management Program clinical trial.
abstract: BACKGROUND
  Information comparing subjective and objective measurements of adherence to study medications and the effects of adherence on treatment-related differences in asthma clinical trials are limited.
  
  
  OBJECTIVE
  We sought to compare subjective and objective measurements of children's adherence to inhaled corticosteroids or placebo and to determine whether adherence to study medications modified treatment-related differences in outcomes.
  
  
  METHODS
  In an ancillary study conducted in 3 of 8 Childhood Asthma Management Program Clinical Centers, adherence was assessed by using self-reported and objective data in 5- to 12-year-old children with mild or moderate asthma who were randomly assigned to 200 μg of inhaled budesonide twice per day (n = 84) or placebo (n = 56) for 4 years. The κ statistic was used to evaluate agreement between self-reported adherence (daily diary cards) and objectively measured adherence (number of doses left in study inhalers). Multivariable analyses were used to determine whether adherence to study treatment modified treatment-related differences in outcomes.
  
  
  RESULTS
  Adherence of less than 80% was seen in 75% of 140 children when adherence was measured objectively but only in 6% of children when measured by means of self-report. There was poor agreement between objective and subjective measurements of adherence of at least 80% (κ = 0.00; 95% CI, -0.05 to 0.04); self-reported adherence over the 4-year period generally overestimated objectively measured adherence (93.6% vs 60.8%, P < .0001). There was little evidence to indicate that adherence modified treatment-related differences in outcomes.
  
  
  CONCLUSIONS
  Researchers should use objective rather than self-reported adherence data to identify clinical trial participants with low levels of adherence to study treatment.
authors: Department of Medicine, Section of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois at Chicago, Ill 60612, USA. jakris@uic.edu
authors: Jerry A
authors: JA
authors: Krishnan
authors: Bruce G
authors: BG
authors: Bender
authors: Frederick S
authors: FS
authors: Wamboldt
authors: Stanley J
authors: SJ
authors: Szefler
authors: N Franklin
authors: NF
authors: Adkinson
authors: Robert S
authors: RS
authors: Zeiger
authors: Robert A
authors: RA
authors: Wise
authors: Andrew L
authors: AL
authors: Bilderback
authors: Cynthia S
authors: CS
authors: Rand
mesh_terms: D000280:Administration, Inhalation; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D019819:Budesonide / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence; D016896:Treatment Outcome
chemical_list: D018927:Anti-Asthmatic Agents; D019819:Budesonide