Aziz, Muhammad Usman

Abstract Rationale Acute exacerbations (AEs) of chronic obstructive pulmonary disease (COPD) are associated with significant morbidity and mortality. Whether mucus plugs are associated with prospective exacerbations has not been examined extensively. Objectives To examine associations between mucus plugs on chest computed tomography (CT) and future moderate-to-severe AEs in two independent cohorts with spirometrically-confirmed COPD. Methods Mucus plugs were visually identified on baseline chest computed tomography scans from smokers with Global Initiative for Chronic Obstructive Lung Disease grade 2–4 COPD enrolled in two multicenter cohort studies: ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) and COPDGene (Genetic Epidemiology of COPD). Associations between ordinal mucus plug score categories (0, 1–2, and ≥3) and prospectively ascertained AEs, defined as worsening respiratory symptoms requiring systemic steroids and/or antibiotics (moderate to severe) and/or emergency room visit or hospitalization (severe), were assessed using multivariable-adjusted zero-inflated Poisson regression; subjects were exacerbation-free at enrollment. Measurements and Main Results Among 3,250 participants in COPDGene (mean age ± SD, 63.7 ± 8.4 yr; FEV1, 50.6 ± 17.8% predicted; 45.1% female) and 1,716 participants in ECLIPSE (age, 63.3 ± 7.1 yr; FEV1, 48.3 ± 15.8% predicted; 36.2% female), 44.4% and 46.0% had mucus plugs, respectively. The incidence rates of AEs were 61.0 (COPDGene) and 125.7 (ECLIPSE) per 100 person-years. Relative to those without mucus plugs, the presence of 1–2 and ≥3 mucus plugs was associated with increased risk (adjusted rate ratio [aRR], 1.07 [95% CI, 1.05–1.09] and 1.15 [1.1–1.2] in COPDGene; aRR, 1.06 [95% CI, 1.02–1.09] and 1.12 [1.04–1.2] in ECLIPSE, respectively) for prospective moderate to severe AEs. The presence of 1–2 and ≥3 mucus plugs was also associated with increased risk for severe AEs during follow-up (aRR, 1.05 [95% CI, 1.01–1.08] and 1.09 [1.02–1.18] in COPDGene; aRR, 1.17 [95% CI, 1.07–1.27] and 1.37 [1.15–1.62] in ECLIPSE, respectively). Conclusions Computed tomography–detected mucus plugs are associated with an increased risk for future COPD AEs.

Importance Airway mucus plugs are common in patients with chronic obstructive pulmonary disease (COPD); however, the association of airway mucus plugging and mortality in patients with COPD is unknown. Objective To determine whether airway mucus plugs identified on chest computed tomography (CT) were associated with increased all-cause mortality. Design, Setting, and Participants Observational retrospective analysis of prospectively collected data of patients with a diagnosis of COPD in the Genetic Epidemiology of COPD cohort. Participants were non-Hispanic Black or White individuals, aged 45 to 80 years, who smoked at least 10 pack-years. Participants were enrolled at 21 centers across the US between November 2007 and April 2011 and were followed up through August 31, 2022. Exposures Mucus plugs that completely occluded airways on chest CT scans, identified in medium- to large-sized airways (ie, approximately 2- to 10-mm lumen diameter) and categorized as affecting 0, 1 to 2, or 3 or more lung segments. Main Outcomes and Measures The primary outcome was all-cause mortality, assessed with proportional hazard regression analysis. Models were adjusted for age, sex, race and ethnicity, body mass index, pack-years smoked, current smoking status, forced expiratory volume in the first second of expiration, and CT measures of emphysema and airway disease. Results Among the 4483 participants with COPD, 4363 were included in the primary analysis (median age, 63 years [IQR, 57-70 years]; 44% were women). A total of 2585 (59.3%), 953 (21.8%), and 825 (18.9%) participants had mucus plugs in 0, 1 to 2, and 3 or more lung segments, respectively. During a median 9.5-year follow-up, 1769 participants (40.6%) died. The mortality rates were 34.0% (95% CI, 32.2%-35.8%), 46.7% (95% CI, 43.5%-49.9%), and 54.1% (95% CI, 50.7%-57.4%) in participants who had mucus plugs in 0, 1 to 2, and 3 or more lung segments, respectively. The presence of mucus plugs in 1 to 2 vs 0 and 3 or more vs 0 lung segments was associated with an adjusted hazard ratio of death of 1.15 (95% CI, 1.02-1.29) and 1.24 (95% CI, 1.10-1.41), respectively. Conclusions and Relevance In participants with COPD, the presence of mucus plugs that obstructed medium- to large-sized airways was associated with higher all-cause mortality compared with patients without mucus plugging on chest CT scans.