Patterns of drug utilisation over age in asthmatic children

Abstract

Background: Children start using drugs for asthma at different ages, and many stop using these after different periods of time. Aim: To study patterns of asthma drug use by age using group-based trajectory models in children. Methods: A retrospective cohort study (2007-2016) in asthmatic children, 5-17 years old in 2 primary care databases: IPCI (NL) and THIN (UK). Asthma was defined as ≥1 asthma disease code and ≥2 prescriptions of respiratory drugs in 1 year. Prescriptions were retrieved by ATC code from patient records. We used group-based trajectory analysis to model 4 trajectories of drug use of any asthma drug (ATC code R03) over age. Drug use was defined as ≥30 days covered by a prescription in a year. Baseline patient characteristics were compared between trajectory groups using χ2-test. Results: We found trajectories of early users, early moderate users, late users and late moderate users with median age of asthma onset of 7, 8, 11 and 13 years, respectively. In both databases early users were significantly more often boys (63-65% in early users vs 41-49% in other groups), had more often eczema (41-48% vs 25-44%) and gastro-esophageal reflux disease (2-4% vs 1-3%) and less often rhinitis, depression or obesity compared to other groups. Conclusion: Within a pediatric primary care population, we found different patterns of drug use over age, associated with various comorbidities. This helps understanding the diversity within pediatric asthma.