Seasonal variation of pediatric asthma exacerbations and its association with asthma phenotypes.

Background

The objective of this study was to examine the associations of blood inflammatory phenotypes with acute pediatric asthma exacerbations during different seasons and the COVID-19 pandemic.

Methods

A retrospective study was conducted involving 32,160 pediatric asthma patients from January 2008 to December 2021. Asthma blood inflammatory phenotypes were categorized based on low (L) and high (H) eosinophils (E) and neutrophils (N) (LBE/HBE: ≥ 0.25 × 10/L and LBN/HBN: ≥ 5 × 10/L, respectively) and logistic regression was used to examine the odds ratio (OR) of outcome variables.

Results

A 10/L increase of neutrophils and eosinophils was associated with a 1.015-fold (95% CI: 1.009-1.021) and a 1.057-fold increase in the OR (95% CI: 1.026-1.088) for asthma exacerbations of hospitalized pediatric asthma patients. An increase in HBE/LBN phenotype was associated with a respective 1.232-fold (95% CI: 1.081-1.404) and 1.248-fold (95% CI: 1.101-1.414) increase in the OR for asthma exacerbations of hospitalized pediatric asthma patients before the COVID-19 pandemic in the winter and autumn seasons. However, an increase of LBE/LBN phenotype was associated with a respective 0.873-fold (95% CI: 0.769-0.991), 0.872-fold (95% CI: 0.771-0.986), and 0.813-fold (95% CI: 0.709-0.932) decrease in the OR for asthma exacerbations in the winter, spring and summer seasons.

Conclusions

HBE/LBN phenotype had a higher risk of asthma exacerbations among hospitalized pediatric asthma patients in the winter and autumn, while LBE/LBN phenotype had a lower risk in the winter, spring, and summer.

Impact

Blood eosinophils and neutrophils have been indicated to have a potential influence on pediatric asthma development and severity. HBE/LBN phenotype was associated with increased asthma exacerbations among hospitalized pediatric asthma patients during winter and autumn. Eosinophil and neutrophil predominance exhibited a higher influence on pediatric asthma exacerbations.

COI Statement

Competing interests: The authors declare no competing interests. Ethics approval: The study procedures followed an approved protocol authorized by the Taipei Medical University Joint Institutional Review Board (TMU-JIRB No N202307036).

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