While the etiopathogenesis of childhood chronic rhinosinusitis (CRS) and asthma is not fully understood, a growing body of research suggests that the breakdown of the sinonasal microbiome may play a significant role in its development and as such could pose a potential target for future treatment strategies.

Here we aimed to assess clinical and microbiological background of asthma persistence from preschool to school age, focusing on atopy and reduced biodiversity of upper airway microbiome

We identified 133 children aged 4-8 years with CRS. We assessed all for allergy status and took nasopharynx swab for microbiome analysis. 117 patients remained under our care for next 5 years. At that time, we analysed all medical records and performed clinical assessments of asthma and CRS.

81 children had asthma diagnosed at the start of the study. After 5 years, the disease persisted in 18 (23%) of them. ANCOM analysis did not show any differences between groups of children with persistent vs remission of asthma in the composition of the nasopharynx microbiome (Figure E2). Receiver operating characteristic curve analysis showed significant association between persistent asthma and biodiversity index of nasopharynx microbiome (AUC=0.7, 95%CI:0.5-0.9; p=0.01). Multivariate model of logistic regression analysis showed that persistence of asthma was independently associated with atopy (OR=10.3, 95%CI: 2.1 to 51.1) and reduced biodiversity of the upper airway microbiome (OR=3.8, 95%CI: 1.1 to 13.3)

Reduced biodiversity concomitant to the atopy increases the risk of persistent asthma in young children with asthma and CRS.