Clinical and lung function outcomes in a cohort of children with severe asthma

Abstract

Background: Uncontrolled severe asthma in children is burdensome and challenging to manage. This study aims to describe outcomes in children with uncontrolled severe asthma managed in a nurse-led severe asthma clinic (SAC). Methods: This retrospective analysis uses data collected from children referred by a paediatric respiratory specialist to a nurse-led SAC for uncontrolled severe asthma between 2014 and 2019. The pre-clinical assessments included a home visit to assess modifiable factors that could be addressed to improve control. A comprehensive lung function analysis was conducted at each visit. Interventions were personalised and included biologic agents. Statistical analysis was performed using nonparametric, two-tailed Mann-Whitney U-test, the parametric Student's t-test, or analysis of variance (ANOVA) as appropriate. Results: Twenty-three children with a median age of 12 years were seen once, and 16 were followed up. Compared to a non-asthmatic (NA) and asthmatic (A) age-matched cohort, children with severe asthma (SA) had a lower FEV1, and FVC% predicted before and after bronchodilator inhalation, and a higher mean Lung Clearance Index [LCI] (10.5 [SA] versus 7.3 [NA] versus 7.6 [A], p = 0.003). Almost 80% of children with SA had an abnormal LCI, and 48% had a reduced FEV1% at the first SAC visit. Asthma control and FEV1% predicted significantly improved at a follow-up visit, while LCI remained abnormal in the majority of children (83%). Conclusion: Over time, many children with severe asthma showed improved clinical outcomes and lung function while lung ventilation inhomogeneities persisted. Future appropriately controlled studies are required to determine if a nurse-led multidisciplinary SAC is associated with better outcomes.

Bronchiolitis hospital admission in infancy is associated with later preschool ventilation inhomogeneity

“…While the magnitude of LCI and S cond changes observed is small and their clinical importance remains to be determined, it is possible that even small changes could have functional relevance. For instance, we and others have also shown that LCI is elevated, although mildly only, in many severe asthmatics as compared with those without severe asthma 43,44 . Several studies have also examined the utility of MBW in preschool asthma, and some 45,46 but not all 47 studies reported higher LCI values with an asthma diagnosis, compared with healthy controls.…”

“…For instance, we and others have also shown that LCI is elevated, although mildly only, in many severe asthmatics as compared with those without severe asthma. 43,44 Several studies have also examined the utility of MBW in preschool asthma, and some 45,46 but not all 47 studies reported higher LCI values with an asthma diagnosis, compared with healthy controls.…”

Impulse oscillometry for the evaluation and management of pediatric asthma

“…With a mass median aerodynamic diameter as low as 1 µm to 1.5 µm, the "extra-fine" ICS formulations can better penetrate small airways than traditional ICS. Observational studies have shown that the use of extra-fine particle ICS reduces exacerbations and improves asthma control [65]. Further studies are necessary to determine whether children with asthma and evidence of SAD would benefit from extra-fine ICS over conventional ICS.…”

Ventilation heterogeneity in children with severe asthma

“…Previous studies of VH in children mostly focused on cohorts with milder asthma and showed higher lung clearance index (LCI) in children with asthma compared to controls [2,3]; however, the average LCIs were usually still within the normal range [4,5]. Others did not stratify by severity [5][6][7] or focused solely on severe asthma [8].…”