The potential influence of asthma control in early life on long-term outcomes in childhood remains largely unknown.
To examine whether asthma control trajectories in the 2 years post-diagnosis in preschoolers are associated with long-term unsatisfactory asthma control.
We conducted a multicenter population-based retrospective cohort study, including 4 Canadian provincial birth cohorts derived from administrative databases. We included preschoolers (<5 years) diagnosed with asthma, defined as having one hospitalization or two physician visits for asthma within two years. Asthma control trajectories, ascertained over four 6-month periods post-diagnosis using a validated index, were classified into: controlled throughout, improving control, fluctuating control, worsening control, and out-of-control throughout. Long-term unsatisfactory control was defined as ≥4 short-acting beta-2 agonist average doses per week or an exacerbation, measured within 6 months before index ages 6, 8, 10, 12, 14, and 16 years. Average risk ratios (RRs) for long-term unsatisfactory control across all index ages were estimated using a robust Poisson model by province and meta-analyzed with a random effects model.
In 50,188 preschoolers with asthma, the pooled average risk of having unsatisfactory control at any index age was 42% (95%CI 34.6%,49.4%). Compared to children controlled throughout, incrementally higher average RRs (95%CI) of long-term unsatisfactory control were observed in each trajectory: improving control, 1.38 (1.28,1.49); fluctuating control, 1.54 (1.40,1.68); worsening control, 1.70 (1.55,1.86); out-of-control throughout, 2.00 (1.80,2.21).
Suboptimal asthma control trajectories shortly following a preschool diagnosis were associated with long-term unsatisfactory asthma control. Early control trajectories appear promising for predicting the risk of long-term adverse outcomes.

Copyright © 2022. Published by Elsevier Inc.