Bronchial smooth muscle remodelling impacts the exacerbation frequency
of severe preschool wheezers
Abstract
INTRODUCTION: Exacerbations in preschool wheezers increase the
risk of impaired lung function and asthma persistence at school age.
Bronchial remodelling-based latent classes identify severe preschool
wheezers at increased risk of frequent exacerbations (>3)
but failed to distinguish those without exacerbation from those with low
exacerbations rate (1-2 exacerbations) in the year following
bronchoscopy. We thus aimed to identify further independent factors
associated with no, low or high exacerbation rates. METHODS: In
this post-hoc analysis, 80 severe preschool wheezers from the
“P’tit Asthme” and “RESPIRE” studies were divided into 3 groups:
No-Ex (0 exacerbation in the year following the bronchoscopy, n=20),
Low-Ex (1-2 exacerbations, n=27) and High-Ex (≥3 exacerbations, n=33).
Associations between variables and groups were assessed using
multinomial logistic regressions. RESULTS: Atopic dermatitis,
age at the first wheezing episode, Haemophilus and
Streptococcus genera in the bronchoalveolar lavage fluid (BALF),
bronchial smooth muscle (BSM) area, reticular basement membrane (RBM)
thickness and RBM-BSM distance were all significantly different between
No-Ex and/or Low-Ex and/or High-Ex. However, only atopic dermatitis, age
at first episode of wheezing, Haemophilus genus in the BALF,
RBM-BSM distance and BSM area were significantly and independently
associated with exacerbation frequency. Among them, the BSM area was the
sole parameter independently associated with each group.
CONCLUSION: While atopic dermatitis, age at the first episode
of wheezing, Haemophilus in BALF, RBM-BSM distance and BSM area
appeared to be relevant independent parameters associated with
exacerbation susceptibility in severe preschool wheezers, only the
increased BSM area discriminated between each of the three-exacerbation
frequency-based groups.