Antibiotic use in children and youths with asthma: a population-based case-control study

RATIONALE: Antibiotics are among the most common medications dispensed to children and youths. The objective of this study was to characterise and compare antibiotic use patterns between children and youths with and without asthma. METHODS: We conducted a population-based nested case–control study using health administrative data from Ontario, Canada, in 2018. All Ontario residents aged 5–24 years with asthma were included as cases. Cases were matched to controls with a 1:1 ratio based on age (within 0.5 year), sex and location of residence. Multivariable conditional logistic regression was used to obtain an odds ratio and 95% confidence interval for having filled at least one antibiotic prescription, adjusted for socioeconomic status, rurality, and presence of common infections, allergic conditions and complex chronic conditions. RESULTS: The study population included 1 174 424 Ontario children and youths aged 5–24 years. 31% of individuals with asthma and 23% of individuals without asthma filled at least one antibiotic prescription. The odds of having filled at least one antibiotic prescription were 34% higher among individuals with asthma compared to those without asthma (OR 1.34, 95% CI 1.32–1.35). In the stratified analysis, the odds ratios were highest in the youngest group of children studied, aged 5–9 years (OR 1.45, 95% CI 1.41–1.48), and in females (OR 1.36, 95% CI 1.34–1.38). CONCLUSION: Asthma is significantly associated with increased antibiotic use in children and youths. This association is the strongest in younger children and in females.