Assessing adherence to inhaled corticosteroids in asthma patients using an integrated measure based on primary and secondary adherence.
OBJECTIVE
There are very few studies on primary adherence (i.e., first filling of a prescription) to inhaled corticosteroids (ICS) in asthma patients; two have involved children. Moreover, adherence can be overestimated when considering only secondary adherence (i.e., following the medication recommendations for a defined period) and ignoring primary adherence. We aimed thus to evaluate the real-world primary and secondary adherence to ICS and to develop an integrated primary and secondary adherence (IPSA) measure.


METHODS
From two clinical databases of pediatric and adult asthma patients, we included 198 children and 206 adults with one ICS prescription recorded in their medical chart between 2010 and 2012 and follow-up data for ≥12 months. Adherence was estimated from written prescriptions and prescription claims data. Primary adherence was defined as filling the ICS prescription at a pharmacy within 12 months. Secondary adherence was defined as the proportion of days covered (PDC) in subjects who filled their prescription at least once. The IPSA was based on the PDC with a correction factor for primary adherence.


RESULTS
Primary adherence to ICS at 12 months was 89.4 % in children and 69.4 % in adults. Secondary adherence at 12 months in children was 33.9 %, and the IPSA was 30.3 %. These values were 52.8 and 36.6 %, respectively, in adults.


CONCLUSIONS
Primary adherence to ICS is low in adults and secondary adherence is poor in children and adults. Using the PDC as a unique measure of adherence led to significant overestimation in adults; IPSA leads to more valid estimates of adherence to ICS.
Faculté de Pharmacie, Université de Montréal, Montréal, QC, Canada. lucie.blais@umontreal.ca.|Hôpital du Sacré-Cœur de Montréal, Montréal, QC, Canada. lucie.blais@umontreal.ca.|Endowment Pharmaceutical Chair AstraZeneca in Respiratory Health, Montréal, QC, Canada. lucie.blais@umontreal.ca.
Lucie
http://orcid.org/0000-0001-8420-3128
L
Blais
Faculté de Pharmacie, Université de Montréal, Montréal, QC, Canada.|Hôpital du Sacré-Cœur de Montréal, Montréal, QC, Canada.
Fatima-Zohra
FZ
Kettani
Faculté de Pharmacie, Université de Montréal, Montréal, QC, Canada.|Hôpital du Sacré-Cœur de Montréal, Montréal, QC, Canada.
Amélie
A
Forget
Faculté de Pharmacie, Université de Montréal, Montréal, QC, Canada.|Endowment Pharmaceutical Chair AstraZeneca in Respiratory Health, Montréal, QC, Canada.|Pharmacy Department, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada.|Centre de Recherche Clinique, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada.
Marie-France
MF
Beauchesne
Faculté de Pharmacie, Université de Montréal, Montréal, QC, Canada.|Hôpital du Sacré-Cœur de Montréal, Montréal, QC, Canada.
Catherine
C
Lemière
Clinical Research and Knowledge Transfer Unit on Childhood Asthma, Research Centre, CHU Sainte-Justine, Montreal, Canada.|Department of Pediatrics, University of Montréal, Montréal, QC, Canada.
Francine M
FM
Ducharme
D000280:Administration, Inhalation; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016208:Databases, Factual; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010594:Pharmacies; D055815:Young Adult; D016903:Drug Monitoring
D000305:Adrenal Cortex Hormones; D018927:Anti-Asthmatic Agents
Administrative databases; Asthma; Inhaled corticosteroids; Primary adherence; Secondary adherence; Written prescriptions
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