Suboptimal asthma control among preschoolers in the 2 years following their asthma diagnosis was associated with long-term unsatisfactory asthma control, according to study results published recently in The Journal of Allergy and Clinical Immunology: In Practice.

In the current study, researchers sought to examine whether asthma control trajectories among preschoolers during the 2 years following their asthma diagnosis were associated with long-term unsatisfactory asthma control. Toward that end, the investigators conducted a multicenter population-based retrospective cohort study that included 50,188 preschoolers from Canadian provincial administrative databases, with data collected between 1990 and 2015. All children included in the study received a physician-confirmed asthma diagnosis before the age of 5 years. Of these children, 64.6% were boys, 88.3% were less than 3 years of age at diagnosis, 63.7% used inhaled corticosteroids in the year prior to or at diagnosis, and 38% were atopic.

Participants’ asthma control status was based on their average weekly doses of short-acting 𝛽2-agonists (SABA), short-courses of oral corticosteroids (OCS), emergency department (ED) visits, and hospitalizations for asthma. Researchers used the Pharmacoepidemiologic Pediatric Asthma Control Index to categorize the preschoolers asthma control over a 6-month period into 4 levels: controlled (≤4 SABA doses per week and 0 OCS, ED visits, or hospitalizations for asthma); partly controlled (4 to <7 SABA doses per week and no OCS, ED visits, or hospitalizations for asthma); poorly controlled (≥7 SABA doses per week or ≥1 OCS/ED visits and no hospitalizations for asthma); and very poorly controlled (≥1 hospitalization for asthma). Unsatisfactory control, long-term, was defined as equal to or greater than 4 short-acting 𝛽2 agonist average doses per week or an exacerbation measured within 6 months before index ages 6, 8, 10, 12, 14, and 16 years.

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Following the asthma diagnosis, an average of 41% of preschoolers were characterized as being “controlled throughout” the 2 years post-diagnosis, 24% had “improving control,” 17% had “fluctuating control,” 10% had “worsening control,” and 8% were characterized as “out-of-control throughout.” Researchers found that the pooled average risk of unsatisfactory control from preschool age to less than 16 years of age was 42%. Incrementally higher average risk ratios (ARR) of long-term unsatisfactory control were observed in each trajectory when compared with children “controlled throughout” (ARR 1.38 for “improving control”; ARR 1.54 for “fluctuating control”; ARR 1.70 for “worsening control”; and ARR 2.00 for “out-of-control throughout”).

Researchers concluded, “suboptimal asthma control trajectories in the 2 years following diagnosis in preschoolers were associated with higher average risks of long-term unsatisfactory control and rates of health care utilization at any given index age until 16 years old.” The investigators further noted that there were incrementally higher risks of adverse long-term outcomes in those with poorer asthma control trajectories, and that  early control trajectories may be a predictor of long-term outcomes.

Disclosures: This research was supported by Industry Partners Boehringer-Ingelheim Canada Ltd., AstraZeneca Canada Inc., and Novartis Canada Ltd. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Longo C, Blais L, Brownell M, et al. Association between asthma control trajectories in preschoolers and long-term asthma control. J Allergy Clin Immunol Pract. Published online January 17, 2022. doi:10.1016/j.jaip.2021.12.033