Lower Airway Disease in Asthmatics with and without Rhinitis

Abstract

Study Objectives The purpose of this study was to determine if asthma with rhinitis and asthma without rhinitis represent distinct forms of disease. Design We performed a prospective cross-sectional study. Participants The study included healthy controls, participants with asthma without rhinitis, and participants with both asthma and rhinitis. Interventions We compared lung function and airway inflammation between the three groups of participants. Results We recruited 32 participants: 12 normals, 8 asthmatics without rhinitis, and 12 with rhinitis. Compared to asthmatics with rhinitis, asthmatics without rhinitis had more severe airflow limitation (FEV₁/FVC = 60.6% [IQR = 22.8] vs. 74.8% [IQR = 7.8] and fewer induced sputum eosinophils (2.8 [IQR = 5.8] and 9.6 [IQR = 23.8], respectively). Sputum interleukin-6 correlated inversely with lung function measured by postbronchodilator FEV₁ in the study cohort (Spearman correlation coefficient = −0.55, p < 0.01). Conclusions Asthmatics without rhinitis tend to have lower lung function and less eosinophilic inflammation in the lung. This small study suggests that asthmatics without rhinitis represent a distinct phenotype of asthma in which low lung function is dissociated from eosinophilic cellular inflammation, and it suggests that larger studies addressing this phenotype are warrented.