Impaired Respiratory System Resistance and Reactance Are Associated With Bronchial Wall Thickening in Persistent Asthma.

BACKGROUND

A recent study demonstrated a significant correlation between bronchial biopsy airway remodeling and quantitative computed tomography looking at bronchial wall thickness.

OBJECTIVE

To identify clinical associations with bronchial wall thickness in moderate to severe asthma.

METHODS

Ninety-two respiratory physician-diagnosed Global Initiative for Asthma-defined patients with moderate to severe asthma were included in this retrospective cohort study. Blinded to all clinical data, 2 senior thoracic radiologists independently measured airway lumen and total airway area at 4 different bronchopulmonary segments using high-resolution computed tomography imaging. We calculated adjusted odds ratios with regard to the association of bronchial wall thickness with spirometry, oscillometry, exacerbations, and nasal polyps.

RESULTS

The pooled analysis for all 4 bronchopulmonary segments showed that an area under reactance curve greater than or equal to 1.0 kPa/L, an R5-R20 ratio (resistance heterogeneity between 5 and 20 Hz divided by total resistance [R5]) of 25% or more, having 2 or more exacerbations per year, and presence of nasal polyposis exhibited adjusted odds ratios of 3.54 (95% CI, 1.22-10.32), 2.89 (95% CI, 1.03-8.05), 4.17 (95% CI, 1.25-13.90), and 9.85 (95% CI, 2.33-41.74), respectively, in their association with a wall area thickness of 50% or more. These translated into a respective 72%, 65%, 76%, and 90% increased likelihood for a wall area thickness of 50% or more.

CONCLUSIONS

Bronchial wall thickness is associated with peripheral airways resistance and reactance, severe exacerbations, and nasal polyposis in persistent asthma.