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Background: Airway mucus plugs are frequently identified on CT scans of patients with COPD with a smoking history without mucus-related symptoms (ie, cough, phlegm [silent mucus plugs])., Research Question: In patients with COPD, what are the risk and protective factors associated with silent airway mucus plugs? Are silent mucus plugs associated with functional, structural, and clinical measures of disease?, Study Design and Methods: We identified mucus plugs on chest CT scans of participants with COPD from the COPDGene study. The mucus plug score was defined as the number of pulmonary segments with mucus plugs, ranging from 0 to 18, and categorized into three groups (0, 1-2, and ≥ 3). We determined risk and protective factors for silent mucus plugs and the associations of silent mucus plugs with measures of disease severity using multivariable linear and logistic regression models., Results: Of 4,363 participants with COPD, 1,739 had no cough or phlegm. Among the 1,739 participants, 627 (36%) had airway mucus plugs identified on CT scan. Risk factors of silent mucus plugs (compared with symptomatic mucus plugs) were older age (OR, 1.02), female sex (OR, 1.40), and Black race (OR, 1.93) (all P values < .01). Among those without cough or phlegm, silent mucus plugs (vs absence of mucus plugs) were associated with worse 6-min walk distance, worse resting arterial oxygen saturation, worse FEV 1 % predicted, greater emphysema, thicker airway walls, and higher odds of severe exacerbation in the past year in adjusted models., Interpretation: Mucus plugs are common in patients with COPD without mucus-related symptoms. Silent mucus plugs are associated with worse functional, structural, and clinical measures of disease. CT scan-identified mucus plugs can complement the evaluation of patients with COPD., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: M. H. C. reported receiving grants from Bayer. A. A. D. reported receiving personal fees from Boehringer-Ingelheim and having a patent for Methods and Compositions Relating to Airway Dysfunction pending (701586-190200USPT). N. L. T. reported that she and/or her husband are general stockholders with no controlling interest in the following: Johnson & Johnson, Kimberly-Clark Corp, Microsoft Corp, Amgen Inc, Bristol Myers Squibb, Cisco Systems Inc, Medtronic, Merck & Co Inc, Procter & Gamble, Crisper Therapeutics, Nvidia, Texas Instruments, Hewlett-Packard, United Health, Abbott Labs, Eli Lilly and Co, AbbVie Inc, and LyondellBasell Industries. Ruben S. J. Estépar reported receiving grants from the National Institutes of Health (NIH) during the conduct of the study. Raúl S. J. Estépar reported being a founder and equity holder of Quantitative Imaging Solutions; receiving grants from Boehringer-Ingelheim; contracts to serve as image core from Insmed and Lung Biotechnology; and personal fees from LeukoLab and Chiesi. A. C. Y. is supported by the NIH [Grants R01HL149861, R01HL164824, U01HL089897]. None declared (S. K. M., H. P. N., S. G., J. L. O., W. R. D., P. N., S. J. K., K. J., P. P. M., M. A., M. U. A., M. Z., A. N. A., R. E., S. S., E. B., W. W., J. B. R.)., (Copyright © 2023 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Rationale/Objective: 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., Methods: Mucus plugs were visually-identified on baseline chest computed tomography (CT) scans from smokers with Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 2-4 COPD enrolled in two multicenter cohort studies: Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) and COPDGene. Associations between ordinal mucus plug score categories (0/1-2/≥3) and prospectively-ascertained AEs, defined as worsening respiratory symptoms requiring systemic steroids and/or antibiotics (moderate-to-severe) and/or ER/hospitalization (severe), were assessed using multivariable-adjusted zero-inflated Poisson regression; subjects were exacerbation-free at enrollment., Results: Among 3,250 participants in COPDGene (mean±SD age 63.7±8.4 years, FEV1 50.6%±17.8% predicted, 45.1% female) and 1,716 participants in ECLIPSE (age 63.3±7.1 years, 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 [95%CI]=1.07[1.05-1.09] and 1.15[1.1-1.2] in COPDGene; aRR=1.06[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[1.01-1.08] and 1.09[1.02-1.18] in COPDGene; aRR=1.17[1.07-1.27] and 1.37[1.15-1.62] in ECLIPSE, respectively)., Conclusion: CT-based mucus plugs are associated with an increased risk for future COPD AEs.

Background: Bronchiectasis in adults with chronic obstructive pulmonary disease (COPD) is associated with greater mortality. However, whether suspected bronchiectasis-defined as incidental bronchiectasis on computed tomography (CT) images plus clinical manifestation-is associated with increased mortality in adults with a history of smoking with normal spirometry and preserved ratio impaired spirometry (PRISm) is unknown., Objective: To determine the association between suspected bronchiectasis and mortality in adults with normal spirometry, PRISm, and obstructive spirometry., Design: Prospective, observational cohort., Setting: The COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) study., Participants: 7662 non-Hispanic Black or White adults, aged 45 to 80 years, with 10 or more pack-years of smoking history. Participants who were former and current smokers were stratified into normal spirometry ( n  = 3277), PRISm ( n  = 986), and obstructive spirometry ( n  = 3399)., Measurements: Bronchiectasis identified by CT was ascertained using artificial intelligence-based measurements of an airway-to-artery ratio (AAR) greater than 1 (AAR >1), a measure of bronchial dilatation. The primary outcome of "suspected bronchiectasis" was defined as an AAR >1 of greater than 1% plus 2 of the following: cough, phlegm, dyspnea, and history of 2 or more exacerbations., Results: Among the 7662 participants (mean age, 60 years; 52% women), 1352 (17.6%) had suspected bronchiectasis. During a median follow-up of 11 years, 2095 (27.3%) died. Ten-year mortality risk was higher in participants with suspected bronchiectasis, compared with those without suspected bronchiectasis (normal spirometry: difference in mortality probability [Pr], 0.15 [95% CI, 0.09 to 0.21]; PRISm: Pr, 0.07 [CI, -0.003 to 0.15]; obstructive spirometry: Pr, 0.06 [CI, 0.03 to 0.09]). When only CT was used to identify bronchiectasis, the differences were attenuated in the normal spirometry (Pr, 0.04 [CI, -0.001 to 0.08])., Limitations: Only 2 racial groups were studied. Only 1 measurement was used to define bronchiectasis on CT. Symptoms of suspected bronchiectasis were nonspecific., Conclusion: Suspected bronchiectasis was associated with a heightened risk for mortality in adults with normal and obstructive spirometry., Primary Funding Source: National Heart, Lung, and Blood Institute., Competing Interests: Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M23-1125.

In order to assess the impact of crustacean zooplankton on phytoplankton and protozoan ciliates in the Sahela reservoir under semi-arid climate, we conducted experiments during the period from July to December 1999 at the deepest point in the lake (15 m). Samplings and measurements were carried out in diffusion chambers submerged in situ over a period of 7 h without (control chambers) and with (experimental chambers) crustacean zooplankton. During these experiments, counts were conducted on phytoplankton and ciliates to determine the abundance and the mortality of these organisms due to zooplankton in each diffusion chambers at t = 0 and t = 7 h of incubation. The study showed that the growth rates of phytoplankton and ciliates populations varied between 0.02 and 0.05 h-1 and from 0.01 to 0.07 h-1, respectively. The mortality caused by zooplankton grazing fluctuated from 0.07 to 0.2 h-1 of phytoplankton and from 0.01 to 0.2 h-1 of ciliates. These mortalities were significantly and positively correlated with the growth rates (r = 0.8; p < 0.02; n = 9). Moreover, the heavy predation by the crustacean zooplankton was exerted on small-sized phytoplankton and ciliates and we demonstrated the relationships between protozoans and zooplankton for the transfer of matter and energy in aquatic food webs. Furthermore, the crustacean zooplankton metabolism was different, whether zooplankton was present in diffusion chambers or in the lake.