Clinical and bronchial parameters associated with the exacerbation frequency of severe preschool wheezers

Recurrent preschool wheezers represent approximately 10% of children under 5 years of age. Among them, those who report frequent exacerbations (ie, or more per year), mainly due to viral and/or bacterial infections, have an increased risk of persistent asthma and poor lung function throughout life. The risk of exacerbation has been previously associated with several clinical and/or biological parameters, including those of bronchial remodeling. The latter corresponds to a poorly reversible structural abnormality of the bronchial tissue (ie, altered epithelial integrity, increased mass of mucus gland and/or bronchial smooth muscle [BSM], increased density of blood vessels, and an increased collagen deposition leading to reticular basement membrane [RBM] thickening and increased submucosal fibrosis). However, it remains unclear whether these factors are independently associated with exacerbation frequency (no exacerbation), infrequent (1 or 2) exacerbations, or frequent (≥3) exacerbations. We aimed to identify the parameters independently associated with short-term subsequent exacerbation frequency (ie, within a year) in 80 severe preschool children (1-5 years old). These children have been pooled from 2independent cohorts with the same inclusion criteria (NCT02806466 and NCT04558671), as described previously.3 All children had uncontrolled severe recurrent preschool wheeze despite receiving high doses of inhaled corticosteroids (ICS) and a second controller. Fiberoptic bronchoscopy with bronchial biopsies was performed during the stable period at least weeks after an exacerbation. A detailed description of methods has been previously published elsewhere.