Late Breaking Abstract - Mucus Plugs and Chronic Bronchitis: Two Distinct COPD Phenotypes

<bold>Background:</bold> Mucus plugs (MP) have emerged as a key feature of COPD pathology and prognosis, being associated with declining lung function, more frequent exacerbations and increased mortality. MPs detected in subjects without chronic bronchitis (CB) symptoms have been termed “silent mucus plugs,” based on symptom‐driven definitions from the SGRQ and ATS‐DLD questionnaire. In addition to the clinical definition (productive cough ≥3 months in the previous year), CB can be defined using responses to the CAT test. <bold>Aim:</bold> To assess the association between CT‐detected MPs and CB using three established definitions. <bold>Methods:</bold> COPD patients (FEV₁/FVC < 0.7) from the EXCEL Cohort underwent inspiratory CT at clinical stability to identify MPs. Patients were classified as MPS+ (≥1 segment with plugs) or MPS– (no plugs). CB was defined by 1) clinical, 2) SGRQ, 3) CAT criteria. <bold>Results:</bold> 98 COPD patients (mean age 74 years; 58% male) were included. Overall, 54 (55.1%) met at least one CB definition: clinical 47.9%, SGRQ 33.6%, CAT 27.5%. Only 18.4% met all three (Fig.1A–B). Among MPS+ patients, CB prevalence was 50.6%, 35.1%, and 27.3% by the three definitions, with 18.2% meeting all three (Fig.1C–D). No significant differences in CB prevalence were observed between MPS+ and MPS–. <bold>Conclusions:</bold> CT‐detected mucus plugs do not correlate with chronic bronchitis, regardless of CB definition, suggesting that MPs and CB represent distinct components of COPD pathobiology. <fig><object-id>erj;66/suppl_69/OA5477/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>