Clinical impact of mucus plugs in bronchiectasis

Mucus plugging is a common radiological finding in bronchiectasis, but its clinical relevance and its association with patient-reported outcomes remain uncertain. We aimed to determine whether the presence of mucus plugs (MP) is associated with worse respiratory symptoms and whether MP extent correlates with symptom severity. We conducted a cross-sectional study including 133 adults with clinically and radiologically confirmed bronchiectasis attending a specialist outpatient clinic. MP were assessed on chest CT using a segment-based scoring system. Respiratory symptoms were evaluated using the Quality of Life-Bronchiectasis Respiratory Symptoms Score (QoL-B RSS) and the Chronic Airways Assessment Test (CAAT). Associations were explored using non-parametric analyses and multivariable regression models adjusted for sex and Bronchiectasis Severity Index (BSI). MP were identified in 88 patients (66%). Compared with those without MP, patients with MP had significantly worse QoL-B RSS (median 77.8 vs. 83.3; p = 0.01) and higher CAAT scores (10.0 vs. 7.0; p = 0.04). MP extent correlated inversely with QoL-B RSS (ρ=-0.27, p = 0.002) and weakly with CAAT (ρ = 0.19, p = 0.03). Patients with high MP burden (> 5 segments) reported significantly worse QoL-B RSS than those without MP (p = 0.01). MP presence was independently associated with chronic Pseudomonas aeruginosa infection after adjustment for sex and disease severity (adjusted OR 5.6, 95% CI 1.31-39.9; p = 0.03). Mucus plugging is associated with worse respiratory symptoms and chronic Pseudomonas aeruginosa infection and may represent a clinically relevant imaging marker of disease activity in bronchiectasis.