Association between asthma control trajectories in preschoolers and disease remission

• Published in: The European respiratory journal Vol. 57; no. 5; p. 2001897
• Main Authors: Longo, Cristina, Blais, Lucie, Brownell, Marni, Quail, Jacqueline M, Sadatsafavi, Mohsen, Forget, Amélie, Turcot, Marc-André, Nie, Yao, Li, Wenbin, Tavakoli, Hamid, Tan, Qier, Fan, Yuxin, Platt, Robert W, Ducharme, Francine M
• Format: Journal Article
• Language: English
• Published: England 01.05.2021
• Subjects: Anticonvulsants - therapeutic use; Asthma - drug therapy; Canada; Child; Child, Preschool; Humans; Proportional Hazards Models; Retrospective Studies; Canada
• ISSN: 0903-1936; 1399-3003
• DOI: 10.1183/13993003.01897-2020

Early disease morbidity has been associated with asthma persistence in wheezing preschoolers; however, whether asthma control trajectories shortly after diagnosis could influence remission is unknown. We examined the association between asthma control trajectories 2 years post-diagnosis in preschoolers and subsequent disease remission. We conducted a multicentre population-based retrospective cohort study consisting of 48 687 children with asthma diagnosed before 5 years old and born between 1990 and 2013 in four Canadian provinces who had prolonged disease activity post-diagnosis. Prolonged disease activity was defined as one or more medical visits or medications for asthma every 6-month period for at least four of the six periods post-diagnosis. Follow-up began at 3 years post-diagnosis (at cohort entry). Remission was defined as 2 consecutive years without drug claims or medical visits for asthma or asthma-like conditions following cohort entry. Asthma control trajectories, ascertained over four 6-month periods following diagnosis using a validated index, were classified as: "controlled throughout", "improving control", "worsening control", "out of control throughout" and "fluctuating control". Adjusted Cox models estimated associations between asthma control trajectories and time to remission. A random effects meta-analysis summarised province-specific hazard ratios (HRs). The pooled remission rate was 8.91 (95% CI 8.80-9.02) per 100 person-years. Compared with children controlled throughout, poorer asthma control was associated with incrementally lower hazard ratios of remission in four other trajectories: improving control (HR 0.89, 95% CI 0.82-0.96), fluctuating control (HR 0.78, 95% CI 0.71-0.85), worsening control (HR 0.68, 95% CI 0.62-0.75) and out of control throughout (HR 0.52, 95% CI 0.45-0.59). Asthma control trajectories 2 years following a diagnosis in preschoolers were associated with remission, highlighting the clinical relevance of documenting control trajectories in early life.