title: Accuracy of the days' supply and the number of refills allowed recorded in Québec prescription claims databases for inhaled corticosteroids.
abstract: Adherence to inhaled corticosteroids (ICS) is a major issue in asthma. This study aimed to estimate the accuracy of the days' supply and number of refills allowed, variables recorded in Québec claims databases and used to estimate adherence, and to develop correction factors, if required. We hypothesised that the accuracy of the days' supply for ICS would be low whereas the accuracy of the number of refills allowed would be high.
  
  
  METHODS
  40 community pharmacies in Québec (Canada) and a medication registry.
  
  
  METHODS
  We collected data for 1108 ICS original prescriptions stored in the 40 pharmacies (sample 1), and we obtained a second sample of 2676 ICS prescriptions selected from reMed, a medication registry (sample 2).
  
  
  METHODS
  We estimated the concordance of the days' supply and number of refills between Québec claims databases and the original prescription from sample 1. We developed a correction factor for the days' supply in sample 1 and validated it in sample 2. Analyses were stratified by age: 0-11 and 12-64 years.
  
  
  RESULTS
  In sample 1, the concordance for the days' supply was 39.6% (95% CI 37.6% to 41.6%) in those aged 0-11 years and 56% (54.9% to 57.2%) in those aged 12-64 years. The concordance increased to 59.4% (58.2% to 60.5%) in those aged 0-11 years and 74.2% (73.5% to 74.9%) in those aged 12-64 years after applying the correction factors in sample 2. The concordance for the refills allowed was 92.1% (91% to 93.1%) in those aged 0-11 years and 93.1% (92.5% to 93.7%) in those aged 12-64 years in sample 1.
  
  
  CONCLUSIONS
  The accuracy of the days' supply was moderate among those aged 0-11 years and substantial among those aged 12-64 years after applying the correction factors. The accuracy of the number of refills was almost perfect in both groups.
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Montréal, Québec, Canada Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada Endowment Pharmaceutical Chair AstraZeneca in Respiratory Health, Montréal, Québec, Canada.
authors.forename: Lucie
authors.initials: L
authors.lastname: Blais
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Anne
authors.initials: A
authors.lastname: Vilain
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Montréal, Québec, Canada Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada.
authors.forename: Fatima-Zohra
authors.initials: FZ
authors.lastname: Kettani
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Montréal, Québec, Canada Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada.
authors.forename: Amélie
authors.initials: A
authors.lastname: Forget
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Lalonde
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Montréal, Québec, Canada Endowment Pharmaceutical Chair AstraZeneca in Respiratory Health, Montréal, Québec, Canada Pharmacy Department, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada Centre de Recherche Clinique Étienne-Le Bel, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Beauchesne
authors.affiliation: Clinical Research and Knowledge Transfer Unit on Childhood Asthma, Research Centre, CHU Sainte-Justine, Montréal, Canada Department of Pediatrics, University of Montréal, Montréal, Québec, Canada.
authors.forename: Francine M
authors.initials: FM
authors.lastname: Ducharme
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Montréal, Québec, Canada Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lemière
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000328:Adult; D017677:Age Distribution; D001249:Asthma / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D016303:Clinical Pharmacy Information Systems / Q000706:statistics & numerical data; D016208:Databases, Factual / Q000706:statistics & numerical data*; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007344:Insurance Claim Reporting / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011792:Quebec; D015203:Reproducibility of Results; D055815:Young Adult; D016903:Drug Monitoring
chemical_list: D000305:Adrenal Cortex Hormones
keywords: EPIDEMIOLOGY; STATISTICS & RESEARCH METHODS