Age-Related Clinical Characteristics, Inflammatory Features, Phenotypes, and Treatment Response in Asthma

Abstract

Emerging evidence suggests that aging affects asthma outcomes, but the mechanism remains largely unexplored. To explore age-related clinical, inflammatory characteristics, phenotypes and treatment response in asthma. This study was a prospective cohort study of asthmatic patients with a 12-month follow-up period in a real-word setting. Clinical, inflammatory and phenotypic characteristics, future risk of exacerbations, and treatment response were assessed across different ages (young: 18-39 years; middle-aged: 40-64 years; elderly: ≥ 65 years). In comparison with young (n = 106) and middle-aged (n = 179) asthmatics, elderly asthmatics (n = 55) had worse airway obstruction, more comorbidities including COPD and diabetes, less atopy, lower levels of IgE and FENO, and were more likely to have late onset and fixed airflow obstruction asthma, and reduced risk of having Type 2 profile asthma. Levels of IFN-γ, IL-17A and IL-8 in induced sputum were significantly increased in elderly asthmatic patients (all P < 0.05). Path analysis indicated that age directly and significantly led to future exacerbations in asthma, partially mediated by an upregulation of airway IFN-γ. Moreover, elderly patients with asthma had reduced treatment response (improvement in FEV1 ≥ 12% or 200 mL, and reduction in Borg sores ≥ 1) (adjusted OR [aOR] = 0.11, 95% CI = [0.02, 0.52], and aOR = 0.12, 95% CI = [0.03, 0.49], respectively). This study supports that asthma in the elderly represents a specific phenotype and indicates that aging can influence asthma in terms of clinical, inflammatory characteristics, exacerbations, and treatment response.