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 remodelling with quantitative computed tomography looking at bronchial wall thickness.

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

Methods: 92 respiratory physician diagnosed GINA-defined moderate-to-severe asthma patients were included in this retrospective cohort study. Blinded to all clinical data, two senior thoracic radiologists independently measured airway lumen and total airway area at four different bronchopulmonary segments using high resolution CT imaging. We calculated adjusted odds ratios (aORs) in regard to the association of bronchial wall thickness with spirometry, oscillometry, exacerbations and nasal polyps.

Results: The pooled analysis for all four bronchopulmonary segments showed that AX≥1.0kPa/L, R5-R20 ratio ≥25%, ≥2 exac/yr and nasal polyposis exhibited aOR (95%CI) of 3.54 (1.22,10.32); 2.89 (1.03,8.05); 4.17 (1.25,13.90); and 9.85 (2.33,41.74) respectively in their association with wall area thickness ≥50%. These translated into a respective 72%, 65%, 76% and 90% increased likelihood for wall area ≥50%.

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