Abstract
Background: Small airways disease (SAD) is a central pathological process in COPD but there is no single gold standard measure with a number of lung function, CT and biological indices commonly used to determine it.
Aims: To compare commonly used markers of SAD and demographics between frequent and infrequent COPD exacerbators and determine if any index differentiates these groups and provides insight into this phenotype.
Methods: Twenty-six GOLD Stage I and II COPD subjects defined as either frequent exacerbators ( ≥ 2 exacerbations per year, n=11) and infrequent exacerbators (≤1 exacerbation per year, n=15) underwent Forced Oscillation Technique (R5-R19, AX), multiple breath nitrogen washout (Sacin), plethysmography (RV/TLC), spirometry (FEV1%, MEF25-75%), paired CT scans (MLD E/I), and bronchoscopy (bronchoalveolar lavage neutrophil % and eosinophils %).
Results: Of the 12 indices compared, the only index that differentiated these groups was Sacin from multiple breath nitrogen washout which was higher in frequent exacerbators median (IQR), 0.42 (0.28) vs 0.25 (0.18), p=0.036. BAL neutrophil % was higher in frequent exacerbators median (IQR), 9.4 (25.40) vs 3.5 (7.75) with a trend towards significance (p=0.08).
Conclusion: Increased ventilation heterogeneity (Sacin) may be a consequence of previous exacerbations or highlight a group of patients prone to exacerbations. This finding maybe associated with neutrophilic inflammation in the distal airways. Results should be confirmed in a larger prospective study to determine if Sacin would be a useful clinical measure of SAD and predicting exacerbation frequency in COPD.
Footnotes
Cite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA1120.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2019