title: Factors associated with concordance between parental-reported use and dispensed asthma drugs in adolescents: findings from the BAMSE birth cohort.
abstract: OBJECTIVE
  Pharmacological treatment is important in asthma care, but there are methodological challenges in measuring how drugs are used by patients. The aim of this study was to investigate the concordance between register data on dispensed drugs and parental-reported use of asthma drugs in adolescents.
  
  
  METHODS
  A cross-sectional study comparing data on dispensed drugs from the Swedish Prescribed Drug Register with data on parental-reported use of asthma drugs among 3 316 adolescents (age 11-14 years) in a population-based birth cohort in Sweden. Sensitivity, specificity, and positive predicted value for different time windows (3, 6, 12, 18, and 24 months) for dispensing in the register were computed. Logistic regression was used to explore factors associated with concordance.
  
  
  RESULTS
  The prevalence of parental-reported use of asthma drugs in the past year was 10.7% (n = 356) compared with 8.1% (n = 269) for dispensed drugs according to the register (p ≤ 0.001). The sensitivity increased with an extended time window in the register, whereas the specificity remained high up to 18 months. Although 90% of the adolescents with asthma had parental-reported use of asthma drugs, 30% of them had no such drugs dispensed in the preceding 18 months. The highest concordance was seen for adolescents with severe asthma (OR 4.6, CI 1.2-17.6).
  
  
  CONCLUSIONS
  An 18-month window is preferable when using dispensing data to study the use of asthma drugs. Still, many adolescents with reported drug use had not purchased any asthma drug in this period. The concordance between parental-reported use and dispensed drugs is higher for adolescents with severe asthma.
authors.affiliation: Department of Medicine, Centre for Pharmacoepidemiology, Karolinska Institutet, Stockholm, Sweden; Department of Healthcare Development, Stockholm County Council, Public Healthcare Services Committee, Stockholm, Sweden.
authors.forename: Elin
authors.initials: E
authors.lastname: Dahlén
authors.forename: Catarina
authors.initials: C
authors.lastname: Almqvist
authors.forename: Anna
authors.initials: A
authors.lastname: Bergström
authors.forename: Björn
authors.initials: B
authors.lastname: Wettermark
authors.forename: Inger
authors.initials: I
authors.lastname: Kull
mesh_terms: D000293:Adolescent; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D002648:Child; D003430:Cross-Sectional Studies; D003625:Data Collection / Q000379:methods; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D010290:Parents; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012042:Registries / Q000706:statistics & numerical data*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013548:Sweden; D013997:Time Factors
chemical_list: D018927:Anti-Asthmatic Agents
keywords: asthma; drug utilization; patient questionnaire; pharmacoepidemiology; register; validation study