Longitudinal lung function decline in subjects with respiratory symptoms

Exposure to ambient air pollution and chronic bronchitis: Findings from over 6.6 million adults in northwestern China

BACKGROUND

Ambient air pollution increases the risk of respiratory mortality and morbidity, but evidence concerning effects of air pollution on chronic bronchitis (CB) is scarce. This study aimed to evaluate the associations of a set of air pollutants with the burden of CB, and to explore potential modifiers on the associations.

METHODS

In 2020, a total of 6,556,440 adults living in the Northwestern region of China were recruited. The Space-Time Extra-Trees model was employed to assess the annual average concentrations of six air pollutants for the three years (2017-2019) before 2020 , and subsequently allocated to the participants based on the latitude and longitude of their home addresses. We investigated the associations between the levels of various air pollutants and the odds of CB using generalized linear mixed models, and conducted multiple sensitivity analyses and subgroup analyses.

RESULTS

The odds of CB displays an approximately linear association with particulate matter with aerodynamic diameter ≤2.5 μm (PM2.5), particulate matter with aerodynamic diameter ≤10 μm (PM10), while it shows a non-linear relationship with gaseous pollutants. In the adjusted model, the odds ratios and 95% confidence intervals for CB per 10 μg/m3 increase in PM2.5, PM10, and sulfur dioxide (SO2) were 1.297 (1.262-1.332), 1.072 (1.064-1.080), and 2.587 (2.186-3.063), respectively. Furthermore, several additional sensitivity analyses demonstrated the stability of these associations. Subgroup analyses found that the aforementioned associations were greater among participants aged below 50 years old and those who smoked and had no leisure time exercise.

CONCLUSION

Long-term exposure to ambient air pollutants may increase the odds of CB, especially among younger people and those with unhealthy lifestyles.

Icenticaftor, a CFTR Potentiator, in COPD: A Multicenter, Parallel-Group, Double-Blind Clinical Trial

Rationale: CFTR (cystic fibrosis transmembrane conductance regulator) dysfunction is associated with mucus accumulation and worsening chronic obstructive pulmonary disease (COPD) symptoms. Objectives: The aim of this phase IIb dose-finding study was to compare a CFTR potentiator, icenticaftor (QBW251), with placebo in patients with COPD and chronic bronchitis. Methods: Patients with COPD on triple therapy for at least three months were randomized to six treatment arms (icenticaftor 450, 300, 150, 75, or 25 mg or placebo twice daily [b.i.d.]) in a 24-week, multicenter, parallel-group, double-blind study. The primary endpoint was change from baseline in trough FEV1 after 12 weeks. Secondary endpoints included change from baseline in trough FEV1 and Evaluating Respiratory Symptoms in COPD (E-RS) total and cough and sputum scores after 24 weeks. Multiple comparison procedure-modeling was conducted to characterize dose-response relationship. Rescue medication use, exacerbations, and change in serum fibrinogen concentration after 24 weeks were assessed in exploratory and post hoc analyses, respectively. Measurements and Main Results: Nine hundred seventy-four patients were randomized. After 12 weeks of icenticaftor treatment, no dose-response relationship for change from baseline in trough FEV1 was observed; however, it was observed for E-RS cough and sputum score. A dose-response relationship was observed after 24 weeks for trough FEV1, E-RS cough and sputum and total scores, rescue medication use, and fibrinogen. A dose of 300 mg b.i.d. was consistently the most effective. Improvements for 300 mg b.i.d. versus placebo were also seen in pairwise comparisons of these endpoints. All treatments were well tolerated. Conclusions: The primary endpoint was negative, as icenticaftor did not improve trough FEV1 over 12 weeks. Although the findings must be interpreted with caution, icenticaftor improved trough FEV1; reduced cough, sputum, and rescue medication use; and lowered fibrinogen concentrations at 24 weeks. Clinical trial registered with www.clinicaltrials.gov (NCT04072887).

CT airway remodelling and chronic cough

RATIONALE

Structural airway changes related to chronic cough (CC) are described in the literature, but so far reported data are rare and non-conclusive. Furthermore, they derive mainly from cohorts with small sample sizes. Advanced CT imaging not only allows airway abnormalities to be quantified, but also to count the number of visible airways. The current study evaluates these airway abnormalities in CC and assesses the contribution of CC in addition to CT findings on the progression of airflow limitation, defined as a decline in forced expiratory volume in 1 s (FEV1) over time.

METHODS

A total of 1183 males and females aged ≥40 years with thoracic CT scans and valid spirometry from Canadian Obstructive Lung Disease, a Canadian multicentre, population-based study has been included in this analysis. Participants were stratified into 286 never-smokers, 297 ever-smokers with normal lung function and 600 with chronic obstructive pulmonary disease (COPD) of different severity grades. Imaging parameters analyses included total airway count (TAC), airway wall thickness, emphysema as well as parameters for functional small airway disease quantification.

RESULTS

Irrespective of COPD presence, CC was not related to specific airway and lung structure features. Independent of TAC and emphysema score, CC was highly associated with FEV1 decline over time in the entire study population, particularly in ever-smokers (p<0.0001).

CONCLUSION

The absence of specific structural CT features independently from COPD presence indicate that other underlying mechanisms are contributing to the symptomatology of CC. On top of derived CT parameters, CC seems to be independently associated with FEV1 decline.

TRIAL REGISTRATION NUMBER

NCT00920348.

The long-term health effects of initiating smoking in adolescence: Evidence from a national longitudinal survey

We estimate the long-term effect of initiating smoking in adolescence on a range of health outcomes later in life. We use the second wave (1996) and the fifth wave (2016-2018) of the National Longitudinal Study of Adolescent to Adult Health (Add Health) and estimate instrumental variables models with school-level fixed effects, where the instruments are the average rate of smoking among friends and the respondents' perceptions about their friends' smoking. We find that smoking in adolescence has a negative impact on 15 of the 28 self-reported, diagnosed, and self-identified health outcomes approximately 20 years later.

Epidemiology of respiratory diseases and associated factors among female textile workers in Pakistan

Objective. The study aimed to estimate the prevalence of byssinosis and other respiratory symptoms among women textile workers and the associated risk factors in 18 spinning mills of Faisalabad and Lahore districts of Punjab, Pakistan. Method. In this case-control study of 1054 female workers, we used the dose-response function to measure the association between dust level and respiratory disorders in cotton textile workers. Results. Working overtime and long working hours per week are significantly associated with self-reported symptoms of byssinosis. Women's age, marital status and wages were significantly associated with mitigating actions (seeing the doctor), while the education of the women was significantly associated with averting action (use of a mask). Conclusion. Regulating working hours and ensuring employees' compliance with the safety standards are expected to mitigate the health problems of female workers.

Clinical Impact of the Bronchiectasis with Chronic Bronchitis Symptoms in COPD: Analysis of a Longitudinal Cohort

Purpose

Bronchiectasis (BE) is a poor prognostic factor in COPD. However, it is not clear whether the poor prognosis is a result of BE alone or accompanying chronic bronchitis symptoms. Therefore, we investigated the effect of chronic bronchitis symptoms on clinical outcomes in COPD patients with BE.

Patients and Methods

We analyzed data of COPD patients from the Korean Obstructive Lung Disease (KOLD) cohort. The presence of BE was verified by chest computed tomography. Chronic bronchitis symptoms were determined using items in the symptomatic domain of the SGRQ, which is also used as an alternative definition of chronic bronchitis (CB). Patients were divided into four groups according to the presence of BE and CB symptoms: BE/CB, BE-only, CB-only, and no BE/CB. Demographic features and clinical outcomes were compared among these groups.

Results

In total, 389 COPD patients were included in the analysis. BE was present in 148 (38%) patients and CB symptoms were found in 123 patients (33.2%). The patients were divided according to BE and CB symptoms, and the numbers and percentages of each group were as follows: BE/CB, 52 (13.4%); BE-only, 96 (24.7%); CB-only, 77 (19.8%); no BE/CB, 164 (42.2%). No significant differences were observed in baseline characteristics of lung function, radiological findings, and inflammatory markers among the four groups. The proportion of annual exacerbators was higher in the BE/CB and CB-only groups than the other two groups. After adjusting other parameters, the BE/CB group was significantly associated with acute exacerbation of COPD (AE-COPD) (OR = 2.110, p = 0.045).

Conclusion

BE accompanying CB symptoms is associated with AE-COPD, while BE alone was not significantly associated. This finding suggests that it is more important to examine chronic bronchitis symptoms of BE to predict acute exacerbation than simply to identify BE in COPD patients.

Pathophysiology of COPD

This article provides an overview of the pathophysiology of chronic obstructive pulmonary disease including the physiological mechanisms that are known precursors. The roles of environmental and genetic causes are considered. α1-Antitrypsin deficiency is also discussed as it relates to the development of airflow obstruction.

Sputum Protein Biomarkers in Airway Diseases: A Pilot Study

Background

Chronic mucous hypersecretion (CMH or chronic bronchitis) per se or when associated with chronic inflammatory airway diseases such as asthma or chronic obstructive pulmonary disease (COPD) has several adverse clinical consequences. The sputum fluid phase has several candidate proteins including mucins which have the potential of being therapeutic targets, but has not yet been explored in-depth. This study aimed at exploring the profile of sputum proteins in various airway diseases.

Methods

Sputum from thirty-one patients with various airway diseases was collected and the fluid phase analyzed by LC-MS/MS and subsequently by sequential window acquisition of all theoretical fragments ion spectra (SWATH) (n = 15) for protein quantitation. Hierarchical clustering and functional grouping were performed.

Results

A total of 185 proteins were quantitated by SWATH of which 21 proteins were identified which could distinguish between the clinical phenotypes by hierarchical clustering. Functional protein clustering revealed 4 groups: those that are inflammation related, oxidative stress related, mucin related and a cytoskeletal and calcium related group. The levels of eight proteins (Azurocidin1, Neutrophil defensin 3, Lactotransferrin, Calmodulin 3, Coronin1A, Mucin 5B, Mucin 5AC and BPI fold containing family B1) were significantly altered (relative to mean) in exacerbator prone subjects compared to nonexacerbators. Another simple but useful metric which emerged from this study was total protein concentration in sputum which was significantly higher in frequent exacerbators.

Conclusion

Sputum proteins can detect the various airway disease clinical phenotypes. Total protein concentration and eight other proteins are biomarkers for frequent exacerbators. The clinical and therapeutic implications of the functional groups of proteins need further evaluation.

A prospective safety and feasibility study of metered cryospray for patients with chronic bronchitis in COPD

Background

No currently approved intervention counteracts airway metaplasia and mucus hypersecretion of chronic bronchitis in COPD. However, metered cryospray (MCS) delivering liquid nitrogen to the tracheobronchial airways ablates abnormal epithelium and facilitates healthy mucosal regeneration. The objective of this study was to evaluate the feasibility, efficacy and safety of MCS in chronic bronchitis.

Methods

Patients with a forced expiratory volume in 1 s of 30–80% predicted who were taking optimal medication were recruited. Primary outcomes were feasibility (completion of treatments), efficacy (3-month change in St George's Respiratory Questionnaire (SGRQ)) and safety (incidence of adverse events). Secondary outcomes were lung function, exercise capacity and additional patient-reported outcomes.

Results

35 patients, 19 male/16 female, aged 47–76 years, Global Initiative for Chronic Obstructive Lung Disease grade I (n=3), II (n=10) and III (n=22), underwent staggered liquid nitrogen treatments to the tracheobronchial tree. 34 patients completed three treatments, each lasting 34.3±12.1 min, separated by 4–6 weeks; one withdrew after the first treatment. ∼1800 doses of MCS were delivered. Clinically meaningful improvements in patient-reported outcomes were observed at 3 months: change in SGRQ −6.4 (95% CI −11.4 to −1.3; p=0.01), COPD Assessment Test (CAT) −3.8 (95% CI −6.4 to −1.3; p<0.01) and Leicester Cough Questionnaire (LCQ) 21.6 (95% CI 7.3 to 35.9; p<0.01). Changes in CAT were durable to 6 months (−3.4, 95% CI −5.9 to −0.9; p=0.01); changes in SGRQ and LCQ were durable to 9 months (−6.9, 95% CI −13.0 to −0.9; p=0.03 and 13.4, 95% CI 2.1 to 24.6; p=0.02, respectively. At 12 months, 14 serious adverse events were recorded in 11 (31.4%) subjects; six (43%) moderate and eight (57%) severe. Nine were respiratory-related: six exacerbations of COPD, two pneumonias and one case of increased coughing; all recovered without sequelae. None were serious device- or procedure-related adverse events.

Conclusion

MCS is safe, feasible and associated with clinically meaningful improvements in multidimensional patient-reported outcomes.

RejuvenAir system treatment for individuals with chronic bronchitis in COPD is safe, feasible, well tolerated, and resulted in clinically meaningful improvements in multidimensional measures of cough, sputum production, breathlessness and quality of lifehttps://bit.ly/30KBfPs

Association of Nonobstructive Chronic Bronchitis With Respiratory Health Outcomes in Adults

IMPORTANCE

Chronic bronchitis has been associated with cigarette smoking as well as with e-cigarette use among young adults, but the association of chronic bronchitis in persons without airflow obstruction or clinical asthma, described as nonobstructive chronic bronchitis, with respiratory health outcomes remains uncertain.

OBJECTIVE

To assess whether nonobstructive chronic bronchitis is associated with adverse respiratory health outcomes in adult ever smokers and never smokers.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study included 22 325 adults without initial airflow obstruction (defined as the ratio of forced expiratory volume in the first second [FEV1] to forced vital capacity [FVC] of <0.70) or clinical asthma at baseline. The National Heart, Lung, and Blood Institute (NHLBI) Pooled Cohorts Study harmonized and pooled data from 9 US general population-based cohorts. Thus present study is based on data from 5 of these cohorts. Participants were enrolled from August 1971 through May 2007 and were followed up through December 2018.

EXPOSURES

Nonobstructive chronic bronchitis was defined by questionnaire at baseline as both cough and phlegm for at least 3 months for at least 2 consecutive years.

MAIN OUTCOMES AND MEASURES

Lung function was measured by prebronchodilator spirometry. Hospitalizations and deaths due to chronic lower respiratory disease and respiratory disease-related mortality were defined by events adjudication and administrative criteria. Models were stratified by smoking status and adjusted for anthropometric, sociodemographic, and smoking-related factors. The comparison group was participants without nonobstructive chronic bronchitis.

RESULTS

Among 22 325 adults included in the analysis, mean (SD) age was 53.0 (16.3) years (range, 18.0-95.0 years), 58.2% were female, 65.9% were non-Hispanic white, and 49.6% were ever smokers. Among 11 082 ever smokers with 99 869 person-years of follow-up, participants with nonobstructive chronic bronchitis (300 [2.7%]) had accelerated decreases in FEV1 (4.1 mL/y; 95% CI, 2.1-6.1 mL/y) and FVC (4.7 mL/y; 95% CI, 2.2-7.2 mL/y), increased risks of chronic lower respiratory disease-related hospitalization or mortality (hazard ratio [HR], 2.2; 95% CI, 1.7-2.7), and greater respiratory disease-related (HR, 2.0; 95% CI, 1.1-3.8) and all-cause mortality (HR, 1.5; 95% CI, 1.3-1.8) compared with ever smokers without nonobstructive chronic bronchitis. Among 11 243 never smokers with 120 004 person-years of follow-up, participants with nonobstructive chronic bronchitis (151 [1.3%]) had greater rates of chronic lower respiratory disease-related hospitalization or mortality (HR, 3.1; 95% CI, 2.1-4.5) compared with never smokers without nonobstructive chronic bronchitis. Nonobstructive chronic bronchitis was not associated with FEV1:FVC decline or incident airflow obstruction. The presence of at least 1 of the component symptoms of nonobstructive chronic bronchitis (ie, chronic cough or phlegm), which was common in both ever smokers (11.0%) and never smokers (6.7%), was associated with adverse respiratory health outcomes.

CONCLUSIONS AND RELEVANCE

The findings suggest that nonobstructive chronic bronchitis is associated with adverse respiratory health outcomes, particularly in ever smokers, and may be a high-risk phenotype suitable for risk stratification and targeted therapies.

Diffuse smoking-related lung diseases: insights from a radiologic-pathologic correlation

Cigarettes are well-recognized risk factors responsible for the emergence of a variety of pathologic conditions affecting both the airways and the lungs. Smoking-related lung diseases can be classified as chronic obstructive pulmonary disease (COPD) and several types of interstitial diseases, such as pulmonary Langerhans cell histiocytosis, bronchiolitis, desquamative interstitial pneumonitis, acute eosinophilic pneumonia, and interstitial fibrosing lung diseases. The evidence of combined lower lung fibrosis and predominant upper lung emphysema is renowned as a distinct clinical entity, named combined pulmonary fibrosis and emphysema. Although computerized tomography permits an adequate classification and distinction of these diseases, the clinical, imaging, and histological features often overlap and coexist in a single patient. Therefore, a combined radiologic and pathologic approach, in the appropriate clinical setting, is useful for best comprehension and distinction of these entities. Our goals are to describe the imaging features in smoking-related lung diseases and how the pathological manifestations translate on high-resolution computerized tomography.

Rate of normal lung function decline in ageing adults: a systematic review of prospective cohort studies

OBJECTIVE

To conduct a systematic review investigating the normal age-related changes in lung function in adults without known lung disease.

DESIGN

Systematic review.

DATA SOURCES

MEDLINE, Embase and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched for eligible studies from inception to February 12, 2019, supplemented by manual searches of reference lists and clinical trial registries.

ELIGIBILITY CRITERIA

We planned to include prospective cohort studies and randomised controlled trials (control arms) that measured changes in lung function over time in asymptomatic adults without known respiratory disease.

DATA EXTRACTION AND SYNTHESIS

Two authors independently determined the eligibility of studies, extracted data and assessed the risk of bias of included studies using the modified Newcastle-Ottawa Scale.

RESULTS

From 4385 records screened, we identified 16 cohort studies with 31 099 participants. All included studies demonstrated decline in lung function-forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) with age. In studies with longer follow-up (>10 years), rates of FEV1 decline ranged from 17.7 to 46.4 mL/year (median 22.4 mL/year). Overall, men had faster absolute rates of decline (median 43.5 mL/year) compared with women (median 30.5 mL/year). Differences in relative FEV1 change, however, were not observed between men and women. FEV1/FVC change was reported in only one study, declining by 0.29% per year. An age-specific analysis suggested the rate of FEV1 function decline may accelerate with each decade of age.

CONCLUSIONS

Lung function-FEV1, FVC and PEFR-decline with age in individuals without known lung disease. The definition of chronic airway disease may need to be reconsidered to allow for normal ageing and ensure that people likely to benefit from interventions are identified rather than healthy people who may be harmed by potential overdiagnosis and overtreatment. The first step would be to apply age, sex and ethnicity-adjusted FEV1/FVC thresholds to the disease definition of chronic obstructive pulmonary disease.

PROSPERO REGISTRATION NUMBER

CRD42018087066.

Fibroblast-specific integrin-alpha V differentially regulates type 17 and type 2 driven inflammation and fibrosis

Fibroproliferative diseases affect a significant proportion of the world's population. Despite this, core mechanisms driving organ fibrosis of diverse etiologies remain ill defined. Recent studies suggest that integrin-alpha V serves as a master driver of fibrosis in multiple organs. Although diverse mechanisms contribute to the progression of fibrosis, TGF-β and IL-13 have emerged as central mediators of fibrosis during type 1/type 17, and type 2 polarized inflammatory responses, respectively. To investigate if integrin-alpha V interactions or signaling is critical to the development of type 2 fibrosis, we analyzed fibroblast-specific integrin-alpha V knockout mice in three type 2-driven inflammatory disease models. While we confirmed a role for integrin-alpha V in type 17-associated fibrosis, integrin-alpha V was not critical to the development of type 2-driven fibrosis. Additionally, our studies support a novel mechanism through which fibroblasts, via integrin-alpha V expression, are capable of regulating immune polarization. We show that when integrin-alpha V is deleted on fibroblasts, initiation of type 17 inflammation is inhibited leading to a deregulation of type 2 inflammation. This mechanism is most evident in a model of severe asthma, which is characterized by a mixed type 2/type 17 inflammatory response. Together, these findings suggest dual targeting of integrin-alpha V and type 2 pathways may be needed to ameliorate fibrosis and prevent rebound of opposing pro-fibrotic and inflammatory mechanisms. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Review of biomarkers to assess the effects of switching from cigarettes to modified risk tobacco products

Context: One approach to reducing the harm caused by cigarette smoking, at both individual and population level, is to develop, assess and commercialize modified risk alternatives that adult smokers can switch to. Studies to demonstrate the exposure and risk reduction potential of such products generally involve the measuring of biomarkers, of both exposure and effect, sampled in various biological matrices.Objective: In this review, we detail the pros and cons for using several biomarkers as indicators of effects of changing from conventional cigarettes to modified risk products.Materials and methods: English language publications between 2008 and 2017 were retrieved from PubMed using the same search criteria for each of the 25 assessed biomarkers. Nine exclusion criteria were applied to exclude non-relevant publications.Results: A total of 8876 articles were retrieved (of which 7476 were excluded according to the exclusion criteria). The literature indicates that not all assessed biomarkers return to baseline levels following smoking cessation during the study periods but that nine had potential for use in medium to long-term studies.Discussion and conclusion: In clinical studies, it is important to choose biomarkers that show the biological effect of cessation within the duration of the study.

Persistent and Newly Developed Chronic Bronchitis Are Associated with Worse Outcomes in Chronic Obstructive Pulmonary Disease

RATIONALE

Chronic bronchitis is, by definition, a chronic condition, but the development and remission of this condition in cigarette smokers with or without chronic obstructive pulmonary disease (COPD) are poorly understood. Also, it is unclear how the persistence or new development of chronic bronchitis affects symptoms and outcomes.

OBJECTIVES

To ascertain the relationship between smoking status and the presence or absence of chronic bronchitis and the subsequent effects on symptoms and outcomes.

METHODS

We analyzed 1,775 current or ex-smokers with GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage 0-IV COPD in phase 2 of the Genetic Epidemiology of COPD (COPDGene) Study, which included subjects after 5 years of follow-up from phase 1. We asked subjects at enrollment and at 5 years of follow-up about symptoms consistent with chronic bronchitis. We divided subjects into four groups: persistent chronic bronchitis- (negative at phase 1/negative at phase 2), resolved chronic bronchitis (positive/negative), new chronic bronchitis (negative/positive), and persistent chronic bronchitis+ (positive/positive). We analyzed respiratory symptoms, health-related quality of life, lung function, exacerbation frequency, and 6-minute walk distance.

MEASUREMENTS AND MAIN RESULTS

Compared with the persistent chronic bronchitis- group, members of the persistent chronic bronchitis+ group were more likely to have continued smoking (53.4%). Subjects with new chronic bronchitis were more likely to have resumed (6.6%) or continued smoking (45.6%), whereas subjects with resolved chronic bronchitis were more likely to have quit smoking (23.5%). Compared with the persistent chronic bronchitis- group, the other groups had a shorter 6-minute walk distance, worse lung function, greater exacerbation frequency, and worse respiratory symptoms. Modified Medical Research Council dyspnea and St. George's Respiratory Questionnaire scores worsened between phase 1 and phase 2 in subjects with new chronic bronchitis but improved in the resolved chronic bronchitis group. On multinomial logistic regression, quitting smoking conferred an odds ratio (OR) of 4.289 (95% confidence interval [CI], 2.689-6.842) for resolved chronic bronchitis, whereas resuming smoking had an OR of 4.585 (95% CI, 2.008-10.471) for new chronic bronchitis. Persistent smoking had an OR of 2.621 (95% CI, 1.677-4.096) and 5.767 (95% CI, 3.702-8.983) for subjects with new chronic bronchitis and subjects with persistent chronic bronchitis, respectively.

CONCLUSIONS

Persistent and newly developed chronic bronchitis are associated with continued or resumed smoking, greater respiratory symptoms, worse health-related quality of life, worse lung function, and greater exacerbation frequency. These findings stress the importance of repeatedly assessing chronic cough and sputum production in smokers to identify those at risk for poor outcomes.

Chronic bronchitis is associated with severe exacerbation and prolonged recovery period in Chinese patients with COPD: a multicenter cross-sectional study

BACKGROUND

Chronic bronchitis (CB) is closely associated with the frequency and severity of chronic obstructive pulmonary disease (COPD) exacerbation. However, little is known about the impact of CB on COPD exacerbations, severe and non-severe, and on recovery from an exacerbation.

METHODS

We conducted a nation-wide multicenter cross-sectional survey in China between September 2007 and December 2008. Eleven hospitals participated in this study. Patients' demographic information, presence of CB, overall numbers of COPD exacerbation and severe exacerbation leading to emergency visit, hospitalization and intensive care unit (ICU) stay in the past year, recovery period following the last exacerbation, and well- or poor-recovery were recorded.

RESULTS

A total of 1,101 patients with COPD were enrolled and 890 (80.8%) had CB. Patients with CB reported more history of frequent exacerbations (≥2/patient/year) (59.6% vs. 50.7%, P=0.019) and severe exacerbation (% emergency visit ≥1: 28.0% vs. 16.6%, P=0.001; % hospitalization ≥1: 51.2% vs. 28.0%, P<0.001; %ICU stay ≥1: 6.5% vs. 1.9%, P=0.009). Recovery period following the last exacerbation was longer in patients with CB (19.0±16.2 vs. 15.2±14.7 days, P=0.003) and more patients with CB reported poor recovery (85.8% vs. 78.4%, P=0.003). Multivariate analyses showed that CB was independently associated with severe exacerbation requiring emergency visit (adjusted OR, 1.512, P=0.048) and hospitalization (adjusted OR, 2.031, P<0.001) and prolonged recovery period (adjusted regression coefficient 2.861, P=0.030).

CONCLUSIONS

CB is associated with frequent exacerbations of COPD in Chinese population, especially severe exacerbations requiring emergency visit and hospitalization admission. Additionally, CB significantly prolongs recovery period following COPD exacerbation.

Changes in definition lead to changes in the clinical characteristics across COPD categories according to GOLD 2017: a national cross-sectional survey in China

Purpose

To investigate how the changes of definition in assessment of Global Initiative for Chronic Obstructive Lung Disease (GOLD) stratification 2017 lead to changes of chronic obstructive pulmonary disease (COPD) patient clinical characteristics across categories in China.

Patients and methods

COPD patients from 11 medical centers in China were stratified into old and new groups A–D twice according to the GOLD 2011 and 2017 comprehensive assessment. Demography and clinical characteristics were compared between old and new groups A–D.

Results

In 1,532 COPD patients, the distribution from group A to D was 330 (21.5%), 132 (8.6%), 411 (26.8%), 659 (43.0%) and 557 (36.4%), 405 (26.4%), 184 (12.0%), 386 (25.2%), respectively according to GOLD 2011 and 2017. 46.7% (500/1,070) patients in high-risk groups were regrouped to low-risk groups. Compared to the old groups A and B, the new groups A and B had a higher proportion of males, lower body mass index, higher modified Medical Research Council (mMRC) grade, poor pulmonary function, more patients with chronic bronchitis, and fewer patients with coronary heart disease and hypertension disease. Compared to the old groups C and D, the new groups C and D had older patients, fewer men, better pulmonary functions, frequent acute exacerbations in the previous year, and more patients with chronic bronchitis, coronary heart disease, or diabetes mellitus. The new group D had more patients with stroke than the old group D.

Conclusion

In China, GOLD 2017 shifted the overall COPD comprehensive assessments distribution to more low-risk groups. The new high-risk groups had more characteristics associated with high risk of acute exacerbation and mortality. Some of the changes in demography and clinical characteristics of the new low-risk groups were associated with high risk of acute exacerbation and/or mortality.

No convincing association between genetic markers and respiratory symptoms: results of a GWA study

BACKGROUND

Respiratory symptoms are associated with accelerated lung function decline, and increased hospitalization and mortality rates in the general population. Although several environmental risk factors for respiratory symptoms are known, knowledge on genetic risk factors is lacking. We aim to identify genetic variants associated with respiratory symptoms by genome-wide association (GWA) analyses.

METHODS

We conducted the first GWA study on cough, dyspnea and phlegm among 7,976 participants in the LifeLines I cohort and used the LifeLines II cohort (n = 5,260) and the Vlagtwedde-Vlaardingen cohort (n = 1,529) for replication.

RESULTS

We identified 50 SNPs that were assessed for replication. Rs16918212, located in the alpha-2-macroglobulin pseudogene 1 (A2MP1), was associated with cough in both the identification (odds ratio (OR) = 0.72, p = 5.41 × 10^-5) and the meta-analyzed replication cohorts (OR = 0.83, p = 0.033). No other significant replicated associations were found.

CONCLUSIONS

Given that only 1 out of 50 SNPs showed significant replication (i.e. 2%) we conclude that we did not find a convincing association between genetic markers and respiratory symptoms. Since, environmental exposures are important risk factors for respiratory symptoms, the next step is to perform a genome-wide interaction (GWI) study to identify genetic susceptibility loci for respiratory symptoms in interaction with known harmful environmental exposures.

Evaluation of Individuals at Risk for COPD: Beyond the Scope of the Global Initiative for Chronic Obstructive Lung Disease

The Global initiative for chronic Obstructive Lung Disease (GOLD) Strategy is a valuable tool for clinicians in the diagnosis and management of patients with established chronic obstructive pulmonary disease (COPD). However, there are no recommendations for the evaluation of individuals, exposed to risk factors, who are most likely to develop COPD. Consequently, it is necessary to consider all of the factors that may play a role in the pathogenesis of COPD: genetic factors, gender, socioeconomic status, disadvantageous factors in childhood, lung diseases and exposure to risk factors such as smoking, biomass fuel smoke, occupational hazards and air pollution. Along with the clinical assessment, periodic spirometry should be performed to evaluate lung function and make possible early detection of individuals who will develop the disease through the rate of forced expiratory volume in 1 second (FEV₁) decline. The first spirometry, periodicity, and clinically significant decline in FEV₁ will encompass the cornerstones of clinical follow up. This approach allows the implementation of important interventions in order to help individuals to cease contact with risk factors and prevent progressive respiratory impairment with the consequent deterioration of quality of life and increased morbidity and mortality.

Alpha-1 antitrypsin deficiency in Canada: regional disparities in diagnosis and management

BACKGROUND

Since 1999, as part of the Alpha1 International Registry (AIR), the Canadian Alpha-1 Antitrypsin Deficiency (AATD) Registry has maintained demographic and medical information volunteered by AATD individuals.

METHODS

We undertook a retrospective chart review to describe the characteristics of registry participants. Inclusion criteria were ZZ phenotype or other severe deficiency and written consent. We reviewed baseline medical records and annual follow-ups, conducted by mail.

RESULTS

The number of registrants ranged from 8.7 per million in British Columbia and Ontario to 1.3 per million in Quebec. Similarly, the rate of augmentation therapy use ranged from 7.7 per million in British Columbia to 0.1 per million in Quebec. 290 patients (146 males), most PiZZ, were enrolled by 2013. Patients with lung disease reported symptoms onset at (mean ± SD) 40 ± 11 years but were diagnosed as AATD at 47 ± 10 years. Typical patients were ex-smokers with respiratory symptoms, severely reduced FEV1, an accelerated rate of FEV1 decline, and minimal bronchodilator response. A subgroup diagnosed by liver disease or familial screening was younger and had better preserved lung function but a similar rate of FEV1 decline. There were 63 deaths, of which 29 were lung-related and 6 were liver-related. Average age at death was 60.5 ± 11.2 years.

DISCUSSION

Most patients experience a diagnostic delay of seven years after symptom onset, a period during which lung health may deteriorate further. There is marked regional variation in the rate of diagnosis and specific therapy usage for AAT in Canada.

The chronic bronchitis phenotype in chronic obstructive pulmonary disease: features and implications

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease (COPD) is a major public health problem that is projected to rank fifth worldwide in terms of disease burden and third in terms of mortality. Chronic bronchitis is associated with multiple clinical consequences, including hastening lung function decline, increasing risk of exacerbations, reducing health-related quality of life, and possibly raising all-cause mortality. Recent data suggest greater elucidation on the risk factors, radiologic characteristics, and treatment regimens. Our goal was to review the literature on chronic bronchitis that has been published in the past few years.

RECENT FINDINGS

A growing body of literature that more carefully describes environmental risk factors, epidemiology, and genetics associated with chronic bronchitis. In addition, as computed tomography technology continues to improve, the radiologic phenotype associated with chronic bronchitis is better understood.

SUMMARY

With these new data, the clinician can recognize the newly described risk factors and the associated phenotype for chronic bronchitis and entertain new treatment options for this high-risk population.

Clinical significance of airway mucus hypersecretion in chronic obstructive pulmonary disease

Airway mucus hypersecretion is one of the most important features of chronic obstructive pulmonary disease (COPD). Airway mucus hypersecretion in COPD patients results in outcomes such as rapid decline of lung function, poor quality of life, and high rate of acute exacerbation, hospitalization and mortality. Nonpharmacologic treatments for airway mucus hypersecretion in COPD include smoking cessation and physical rehabilitation. Pharmacologic therapies include expectorants, mucolytics, methylxanthines, beta-adrenergic receptor agonists, anticholinergics, glucocorticoids, phosphodiesterase-4 inhibitors, antioxidants, and antibiotics. Novel drugs with promising prospects are currently under clinical trials.

Natural history of COPD: Focusing on change in FEV1

The natural history of chronic obstructive pulmonary disease (COPD) is usually described with a focus on change in forced expiratory volume in 1 s (FEV1 ) over time as this allows for exploration of risk factors for an accelerated decline-and thus of developing COPD. From epidemiological studies we have recognized important risk factors such as smoking, exposure to biomass and occupational exposures, but we have also learnt about features such as chronic bronchitis, airway hyper-responsiveness and asthma that seem to accelerate decline in FEV1 independent of exposures. In addition we are gradually beginning to better link early life events to subsequent risk of disease in adulthood. Although more complicated, our current understanding of COPD has come a long way from being a simple image of smoking leading to poor lungs.

Factors associated with the annual change in forced expiratory volume in 1 second of officially acknowledged victims of pollution-related illness in improved environments: a longitudinal study

[Purpose] We examined factors affecting annual change in pulmonary function in residents previously exposed to air pollution in an area where pollution has been reduced and a long time period has elapsed. [Subjects and Methods] Data of 730 officially acknowledged victims of pollution-related illness from an annual survey during 2000 to 2009 were analyzed. The primary outcome was forced expiratory volume in 1 second (FEV₁), along with factors such as age, body composition, smoking habits, respiratory symptoms, and classification of medical management (an index of the need for treatment). Multiple regression analyses were used to identify factors associated with the annual change in FEV₁. [Results] Three significant factors were identified: smoking habit, classification of medical management, and gender. Smoking habits and classification of medical management had stronger effects on the annual change in FEV₁ than gender. [Conclusion] With an improved environment, continuation of smoking accelerates the decline in FEV₁.

Presentation of respiratory symptoms prior to diagnosis in general practice: a case-control study examining free text and morbidity codes

OBJECTIVE

General practitioners can record patients' presenting symptoms by using a code or free text. We compared breathlessness and wheeze symptom codes and free text recorded prior to diagnosis of ischaemic heart disease (IHD), chronic obstructive pulmonary disease (COPD) and asthma.

DESIGN

A case-control study.

SETTING

11 general practices in North Staffordshire, UK, contributing to the Consultations in Primary Care Archive consultation database.

PARTICIPANTS

Cases with an incident diagnosis of IHD, COPD or asthma in 2010 were matched to controls (four per case) with no such diagnosis. All prior consultations with codes for breathlessness or wheeze symptoms between 2004 and 2010 were identified. Free text of cases and controls were also searched for mention of these symptoms.

RESULTS

592 cases were identified, 194 (33%) with IHD, 182 (31%) with COPD and 216 (37%) with asthma. 148 (25%) cases and 125 (5%) controls had a prior coded consultation for breathlessness. Prevalence of a prior coded symptom of breathlessness or wheeze was 30% in cases, 6% in controls. Median time from first coded symptom to diagnosis among cases was 57 weeks. After adding symptoms recorded in text, prevalence rose to 62% in cases and 25% in controls. Median time from first recorded symptom increased to 144 weeks. The associations between diagnosis of cases and prior symptom codes was strong IHD relative risk ratio (RRR) 3.21 (2.15 to 4.79); COPD RRR 9.56 (6.74 to 13.60); asthma RRR 10.30 (7.17 to 14.90).

CONCLUSIONS

There is an association between IHD, COPD and asthma diagnosis and earlier consultation for respiratory symptoms. Symptoms are often noted in free text by GPs long before they are coded. Free text searching may aid investigation of early presentation of long-term conditions using GP databases, and may be an important direction for future research.

Diagnosis and early detection of COPD using spirometry

The standard respiratory function test for case detection of chronic obstructive pulmonary disease (COPD) is spirometry. The criterion for diagnosis defined in guidelines is based on the FEV1/FVC ratio forced expiratory ratio (FER) and its severity is based on forced expiratory volume in one second (FEV1) from measurements obtained during maximal forced expiratory manoeuvres. Spirometry is a safe and practical procedure, and when conducted by a trained operator using a spirometer that provides quality feedback, the majority of patients can be coached to provide acceptable and repeatable results. This allows potentially wide application of testing to improve recognition and diagnosis of COPD, such as for case finding in primary care. However, COPD remains substantially under diagnosed in primary care and a major reason for this is underuse of spirometry. The presence of symptoms is not a reliable indicator of disease and diagnosis is often delayed until more severe airflow obstruction is present. Early diagnosis is worthwhile, as it allows risk factors for COPD such as smoking to be addressed promptly and treatment optimised. Paradoxically, investigation of the patho-physiology in COPD has shown that extensive small airway disease exists before it is detectable with conventional spirometric indices, and methods to detect airway disease earlier using the flow-volume curve are discussed.

Changes in lung function in older people from the English Longitudinal Study of Ageing

BACKGROUND

Decline in lung function with increasing age is common in older people. However, the rate of decline using the forced expiratory volume in 1 s (FEV1) in a longitudinal study in the elderly community dwellers is unknown.

METHODS

We analyzed data from the English Longitudinal Study of Ageing on people 50 years and older who had FEV1 measurement at Wave 2 and Wave 4 of 4 years of follow-up, respectively. A random coefficient model was employed to examine the changes in FEV1 and predict differences in the levels of FEV1 in older people.

RESULTS

A total of 4224 participants were included in the study. The mean (± standard deviation [SD]) rate of change in FEV1 was a decline of 32.92 ± 0.96 ml/year. The absolute difference in mean FEV1 level between female and male participants was 767.07 ± 16.6 ml. It was 253.91 ± 22.7 ml lower in current smokers than in nonsmokers, 73.67 ± 18.67 ml lower in participants with a history of sputum in winter months than in participants without sputum, 63.32 ± 7.07 ml lower in participants with a higher dyspnea score than in participants with a lower dyspnea score and 67.77 ± 15.87 ml higher in participants with good health compared to participants with fair/poor health status. One microgram increase in C-reactive protein level lowered FEV1 by 4.66 ± 0.86 ml and one Hb of hemoglobin increased the FEV1 level by 4.78 ± 0.77 ml. All were statistically significant at p < 0.001.

CONCLUSIONS

The average rate of FEV1 decline in older people without respiratory diseases was found to be high. Lower level of FEV1 was also observed in current smokers, females, those with a history of sputum in winter months and in participants with higher dyspnea score or in those with poorer health status.

Clinical and computed tomographic predictors of chronic bronchitis in COPD: a cross sectional analysis of the COPDGene study

BACKGROUND

Chronic bronchitis (CB) has been related to poor outcomes in Chronic Obstructive Pulmonary Disease (COPD). From a clinical standpoint, we have shown that subjects with CB in a group with moderate to severe airflow obstruction were younger, more likely to be current smokers, male, Caucasian, had worse health related quality of life, more dyspnea, and increased exacerbation history compared to those without CB. We sought to further refine our clinical characterization of chronic bronchitics in a larger cohort and analyze the CT correlates of CB in COPD subjects. We hypothesized that COPD patients with CB would have thicker airways and a greater history of smoking, acute bronchitis, allergic rhinitis, and occupational exposures compared to those without CB.

METHODS

We divided 2703 GOLD 1-4 subjects in the Genetic Epidemiology of COPD (COPDGene®) Study into two groups based on symptoms: chronic bronchitis (CB+, n = 663, 24.5%) and no chronic bronchitis (CB-, n = 2040, 75.5%). Subjects underwent extensive clinical characterization, and quantitative CT analysis to calculate mean wall area percent (WA%) of 6 segmental airways was performed using VIDA PW2 (http://www.vidadiagnostics.com). Square roots of the wall areas of bronchi with internal perimeters 10 mm and 15 mm (Pi10 and Pi15, respectively), % emphysema, %gas trapping, were calculated using 3D Slicer (http://www.slicer.org).

RESULTS

There were no differences in % emphysema (11.4 ± 12.0 vs. 12.0 ± 12.6%, p = 0.347) or % gas trapping (35.3 ± 21.2 vs. 36.3 ± 20.6%, p = 0.272) between groups. Mean segmental WA% (63.0 ± 3.2 vs. 62.0 ± 3.1%, p < 0.0001), Pi10 (3.72 ± 0.15 vs. 3.69 ± 0.14 mm, p < 0.0001), and Pi15 (5.24 ± 0.22 vs. 5.17 ± 0.20, p < 0.0001) were greater in the CB + group. Greater percentages of gastroesophageal reflux, allergic rhinitis, histories of asthma and acute bronchitis, exposures to dusts and occupational exposures, and current smokers were seen in the CB + group. In multivariate binomial logistic regression, male gender, Caucasian race, a lower FEV1%, allergic rhinitis, history of acute bronchitis, current smoking, and increased airway wall thickness increased odds for having CB.

CONCLUSIONS

Histories of asthma, allergic rhinitis, acute bronchitis, current smoking, a lower FEV1%, Caucasian race, male gender, and increased airway wall thickness are associated with CB. These data provide clinical and radiologic correlations to the clinical phenotype of CB.

Clinical issues of mucus accumulation in COPD

Airway mucus is part of the lung's native immune function that traps particulates and microorganisms, enabling their clearance from the lung by ciliary transport and cough. Mucus hypersecretion and chronic productive cough are the features of the chronic bronchitis and chronic obstructive pulmonary disease (COPD). Overproduction and hypersecretion by goblet cells and the decreased elimination of mucus are the primary mechanisms responsible for excessive mucus in chronic bronchitis. Mucus accumulation in COPD patients affects several important outcomes such as lung function, health-related quality of life, COPD exacerbations, hospitalizations, and mortality. Nonpharmacologic options for the treatment of mucus accumulation in COPD are smoking cessation and physical measures used to promote mucus clearance. Pharmacologic therapies include expectorants, mucolytics, methylxanthines, beta-adrenergic receptor agonists, anticholinergics, glucocorticoids, phosphodiesterase-4 inhibitors, antioxidants, and antibiotics.

Chronic productive cough is associated with death in smokers with early COPD

Cough and phlegm are common in COPD. Previous studies have shown conflicting evidence regarding their association with mortality and lung function. We sought to better understand how cough and phlegm impact mortality and lung function in COPD. We analyzed data from the Lung Health Study, consisting of 5,887 smokers with mild to moderate airflow obstruction followed longitudinally. We assessed the association between baseline symptoms of cough alone, phlegm alone, and cough and phlegm with 12.5-year mortality and annual lung function decline. Average age at entry was 48.5 years (± 6.8) with 63% males and 4% African Americans. Cough alone was present in 17%, phlegm alone in 12%, while 31% had both. Neither symptom alone was associated with death, but the combination was associated with increased risk of death after adjustment for age, gender, race, smoking status at year 5, pack-years smoked, randomization group, baseline FEV1 percent predicted (HR 1.27, 95% CI 1.02-1.59). Individuals with cough and phlegm together more commonly died of respiratory causes than those without. Cough with phlegm was associated with 48 mL lower baseline FEV1 (95% CI -90, -6), while neither symptom alone was associated with baseline FEV1. No symptom was associated with FEV1 longitudinally. Cough and phlegm together are associated with mortality and lung function decrement in mild-to-moderate COPD, independent of lung function and smoking status. Respiratory causes of death are common among those with cough and phlegm. Such information can help to identify subsets of individuals with COPD having higher risk for adverse outcomes.

Severe chronic bronchitis in advanced emphysema increases mortality and hospitalizations

BACKGROUND

Chronic bronchitis in COPD has been associated with an increased exacerbation rate, more hospitalizations, and an accelerated decline in lung function. The clinical characteristics of patients with advanced emphysema and chronic bronchitis have not been well described.

METHODS

Patients randomized to medical therapy in the National Emphysema Treatment Trial were grouped based on their reports of cough and phlegm on the St. George's Respiratory Questionnaire(SGRQ) at baseline: chronic bronchitis(CB+) and no chronic bronchitis(CB-). The patients were similarly categorized into severe chronic bronchitis(SCB+) or no severe chronic bronchitis (SCB-) based on the above definition plus report of chest trouble. Kaplan-Meier survival analysis was used to determine the relationships between chronic bronchitis and severe chronic bronchitis and survival and time to hospitalization. Lung function and SGRQ scores over time were compared between groups.

RESULTS

The CB+(N = 234; 38%) and CB- groups(N = 376; 62%) had similar survival (median 60.8 versus 65.7 months, p = 0.19) and time to hospitalization (median 26.9 versus 24.9 months, p = 0.84). The SCB+ group(N = 74; 12%) had worse survival (median 47.7 versus 65.7 months, p = 0.02) and shorter time to hospitalization (median 18.5 versus 26.7 months, p = 0.02) than the SCB- group (N = 536; 88%). Mortality and hospitalization rates were not increased when chest trouble was analyzed by itself. The CB+ and CB-groups had similar lung function and SGRQ scores over time. The SCB+ and SCB-groups had similar lung function over time, but the SCB+ group had significantly worse SGRQ scores.

CONCLUSIONS

Severe chronic bronchitis is associated with worse survival, shorter time to hospitalization, and worse health-related quality of life.

Variations in FEV₁ decline over time in chronic obstructive pulmonary disease and its implications

PURPOSE OF REVIEW

This article reviews findings from longitudinal observational studies in both general and chronic obstructive pulmonary disease (COPD) populations, as well as from intervention trials in COPD, in which the annual rate of decline in forced expired volume in 1  s (FEV₁) has been measured. The purpose of the review is to describe the individual variability in rates of decline in FEV₁ within these populations, explore the factors contributing to this variability and discuss its implications.

RECENT FINDINGS

Individual rates of decline in FEV₁ have been found to vary considerably across participants with COPD in both observational cohorts and intervention trials from decreases as rapid as 150-200  ml per year to increases of up to approximately 150  ml per year, with mean rates of decline ranging from 33 to 69  ml per year. Aside from technical and biologic (e.g., time of day, season, weather, fatigue) sources of variation, other influential factors have included smoking status (most notably current versus former smoking), baseline smoking intensity, baseline lung function, airway hyperresponsiveness, exacerbation frequency, and, variably, age and sex. The presence of emphysema may also be a determinant, as well as certain biomarkers and gene variants.

SUMMARY

The wide distribution of individual rates of decline in FEV₁ includes especially rapid and slow declines. Future research is needed to identify biomarkers that both are predictive of a rapid decline within individuals who might then be targeted for special intervention and might also serve as surrogate endpoints in interventional trials.

Factors associated with lung function decline in patients with non-tuberculous mycobacterial pulmonary disease

Background

There is paucity of risk factors on lung function decline among patients with non-tuberculous mycobacteria (NTM) pulmonary disease in literature.

Methods

Patients with NTM pulmonary disease between January 2000 and April 2011 were retrospectively selected. Sixty-eight patients had at least two pulmonary function tests within a mean follow-up period of 47 months.

Results

Sixty-eight patients were included. They had a median age of 65 years and 65% had impaired lung function (Forced expiratory volume in 1 second [FEV₁] <80% of predicted value). The mean FEV₁ decline was 48 ml/year. By linear regression, younger age (beta: 0.472, p<0.001), initial FEV₁>50% of predicted value (beta: 0.349, p = 0.002), male sex (beta: 0.295, p = 0.018), bronchiectasis pattern (beta: 0.232, p = 0.035), and radiographic score >3 (beta: 0.217, p = 0.049) were associated with greater FEV₁ decline. Initial FEV₁>50% of predicted value (beta: 0.263, p = 0.032) was also associated with greater FVC annual decline, whereas M. kansasii pulmonary disease was marginally associated with greater annual FVC decline (beta: 0.227, p = 0.062).

Conclusions

NTM pulmonary disease is associated with greater decline in lung function in patients who are young, male, with bronchiectasis, and with a high radiographic score. Special attention should be given to patients with these risk factors.

Chronic bronchitis and chronic obstructive pulmonary disease

Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD). It has numerous clinical consequences, including an accelerated decline in lung function, greater risk of the development of airflow obstruction in smokers, a predisposition to lower respiratory tract infection, higher exacerbation frequency, and worse overall mortality. CB is caused by overproduction and hypersecretion of mucus by goblet cells, which leads to worsening airflow obstruction by luminal obstruction of small airways, epithelial remodeling, and alteration of airway surface tension predisposing to collapse. Despite its clinical sequelae, little is known about the pathophysiology of CB and goblet cell hyperplasia in COPD, and treatment options are limited. In addition, it is becoming increasingly apparent that in the classic COPD spectrum, with emphysema on one end and CB on the other, most patients lie somewhere in the middle. It is known now that many patients with severe emphysema can develop CB, and small airway pathology has been linked to worse clinical outcomes, such as increased mortality and lesser improvement in lung function after lung volume reduction surgery. However, in recent years, a greater understanding of the importance of CB as a phenotype to identify patients with a beneficial response to therapy has been described. Herein we review the epidemiology of CB, the evidence behind its clinical consequences, the current understanding of the pathophysiology of goblet cell hyperplasia in COPD, and current therapies for CB.

Role of Epithelial Cells in Chronic Inflammatory Lung Disease

Airborne pathogens entering the lungs first encounter the mucus layer overlaying epithelial cells as a first line of host defense [1, 2]. In addition to serving as the physical barrier to these toxic agents, intact epithelia also are major sources of various macromolecules including antimicrobial agents, antioxidants and antiproteases [3, 4] as well as proinflammatory cytokines and chemokines that initiate and amplify host defensive responses to these toxic agents [5]. Airway epithelial cells can be categorized as either ciliated or secretory [6]. Secretory cells, such as goblet cells and Clara cells, are responsible for the production and secretion of mucus along the apical epithelial surface and, in conjunction with ciliated cells, for the regulation of airway surface liquid viscosity. In addition, submucosal mucus glands connect to the airway lumen through a ciliated duct that propels mucins outward. These glands are present in the larger airways between bands of smooth muscle and cartilage. See Fig. 1.

Respiratory symptoms and peripheral airways disease in a cross-sectional study on a random population sample

OBJECTIVES

Respiratory symptoms are associated with spirometry results but more strongly with smoking history, suggesting that alterations in the lung other than those revealed by spirometry contribute to cause symptoms. Smoking may cause obstruction of peripheral airways that is poorly detected by spirometry. The slope of phase III of the single-breath nitrogen (N(2)) test detects smoking-induced alterations in smokers before spirometry is impaired. The aim of the present investigation was to study the association between respiratory symptoms and the slope of phase III adjusting for spirometry results and smoking history.

DESIGN

Single-centre retrospective cross-sectional study.

SETTING

University hospital in Gothenburg, Sweden.

PARTICIPANTS

A random population sample of 430 elderly men.

METHODS

The presence of seven different respiratory symptoms were analysed by a multiple logistic regression model in relation to spirometry results, smoking history (pack-years) and the slope of phase III in a population sample of 430 elderly men, age span 50-67 years. Furthermore, smoking normalised values of the slope of phase III were calculated and differences between subjects reporting/not reporting symptoms were tested.

RESULTS

The presence of some cough symptoms was significantly associated with a steep slope of phase III also when adjusting for spirometry results and smoking history. Furthermore, smoking normalised slope of phase III was significantly steeper among subjects with cough symptoms compared to those without cough symptoms.

CONCLUSIONS

Cough symptoms may be an effect of abnormalities in peripheral airways at least among elderly men.

The effect of chronic sputum production on respiratory symptoms in severe COPD

BACKGROUND

Chronic sputum production is a significant but variable complaint in COPD; its effect on symptom burden has not been comprehensively described. We sought to characterize the daily burden of chronic sputum production in severe COPD and the phenotype of those with chronic sputum symptoms.

METHODS

We studied 50 outpatients with severe COPD who used an electronic diary to document peak expiratory flow (PEF) and respiratory symptoms daily for up to 2 years. A sputum index was derived based on complaints of sputum quantity, color, and consistency, and patients were divided into groups based on average daily sputum index (Low, Medium, High). The presence and severity of respiratory symptoms were scored by a novel method using daily changes in symptoms and PEF from baseline and were categorized into mild, moderate, and severe. Percent emphysema was measured using quantitative CT.

RESULTS

In the 14,500 observation days, severe symptom days were greater in the Medium and High groups (379/6089, 1609/4091, and 2624/4317 observation days in Low, Medium, and High, p < 0.0001). The same trend was found even when sputum complaints were removed from the symptom severity score. Observed/predicted PEF ratio was lower in the High group (0.56 ± 0.24, 0.55 ± 0.19, and 0.42 ± 0.12 in each group, p < 0.05 for High compared to Medium and Low). Percent emphysema inversely correlated with average sputum index and quantity (r = -0.449 and r = -0.584, respectively, p < 0.05).

CONCLUSIONS

Increased sputum production in severe COPD is frequently encountered daily and is associated with more respiratory symptoms, worse airflow obstruction, and less emphysema.

Interpreting screening questionnaires: specific respiratory symptoms and their relationship to objective test results

OBJECTIVE

To better delineate the relationship between responses to screening respiratory symptom questionnaires and various pulmonary function test results.

METHODS

Spirometry, methacholine challenge, standardized questionnaires, smoking, medical, and work histories were recorded at initial and 5-year follow-up surveys among 411 participants. Percent-predicted forced expiratory volume in 1 second (ppFEV1), 5-year FEV1 decline, and proportion of methacholine responders (% hyper-responders) were compared with questionnaire responses utilizing generalized estimating equations modeling and analysis of variance.

RESULTS

Significant associations were found between ppFEV1 and cough, phlegm, dyspnea, or ever wheezing; between greater percentage of hyper-responders and dyspnea with wheezing, ever/persistent wheezing, or history of asthma/hay fever; and between accelerated FEV1 decline and new onset dyspnea with wheezing, phlegm, or persistent wheeze.

CONCLUSIONS

Particular respiratory symptoms reported on screening questionnaires are associated with specific physiologic abnormalities, enhancing questionnaire utility in workplace health surveillance.

Cough and sputum production as risk factors for poor outcomes in patients with COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality in developed countries, and its prevalence is projected to increase over the coming decades. According to the World Health Organization, COPD will become the third leading cause of death worldwide by 2020. COPD has a chronic and progressive course, and is often aggravated by exacerbations, which typically arise as a result of bronchial infection. Exacerbations are characterised by periods of increasing acute symptoms, particularly cough, dyspnoea and production of sputum, which worsen airflow obstruction, further impair quality of life and generally require a change in regular medication. Exacerbations are the most common cause of medical visits, hospital admissions and death in patients with COPD, and frequent exacerbations worsen health status and may cause a permanent decline in lung function. Chronic cough and sputum production are common in the general population, but significantly more prevalent in patients with respiratory disorders; these symptoms have been suggested as a risk factor for exacerbations of COPD. This article will review the consequences of chronic cough and sputum production in patients with COPD and analyse whether these risk factors may be useful for identifying a specific phenotype of patient that requires different management to reduce the occurrence of exacerbations.

Systematic review of the evidence relating FEV1 decline to giving up smoking

BACKGROUND

The rate of forced expiratory volume in 1 second (FEV1) decline ("beta") is a marker of chronic obstructive pulmonary disease risk. The reduction in beta after quitting smoking is an upper limit for the reduction achievable from switching to novel nicotine delivery products. We review available evidence to estimate this reduction and quantify the relationship of smoking to beta.

METHODS

Studies were identified, in healthy individuals or patients with respiratory disease, that provided data on beta over at least 2 years of follow-up, separately for those who gave up smoking and other smoking groups. Publications to June 2010 were considered. Independent beta estimates were derived for four main smoking groups: never smokers, ex-smokers (before baseline), quitters (during follow-up) and continuing smokers. Unweighted and inverse variance-weighted regression analyses compared betas in the smoking groups, and in continuing smokers by amount smoked, and estimated whether beta or beta differences between smoking groups varied by age, sex and other factors.

RESULTS

Forty-seven studies had relevant data, 28 for both sexes and 19 for males. Sixteen studies started before 1970. Mean follow-up was 11 years. On the basis of weighted analysis of 303 betas for the four smoking groups, never smokers had a beta 10.8 mL/yr (95% confidence interval (CI), 8.9 to 12.8) less than continuing smokers. Betas for ex-smokers were 12.4 mL/yr (95% CI, 10.1 to 14.7) less than for continuing smokers, and for quitters, 8.5 mL/yr (95% CI, 5.6 to 11.4) less. These betas were similar to that for never smokers. In continuing smokers, beta increased 0.33 mL/yr per cigarette/day. Beta differences between continuing smokers and those who gave up were greater in patients with respiratory disease or with reduced baseline lung function, but were not clearly related to age or sex.

CONCLUSION

The available data have numerous limitations, but clearly show that continuing smokers have a beta that is dose-related and over 10 mL/yr greater than in never smokers, ex-smokers or quitters. The greater decline in those with respiratory disease or reduced lung function is consistent with some smokers having a more rapid rate of FEV1 decline. These results help in designing studies comparing continuing smokers of conventional cigarettes and switchers to novel products.

Long-term effects of work cessation on respiratory health of textile workers: a 25-year follow-up study

RATIONALE

The degree to which chronic respiratory health effects caused by exposures to cotton dust and endotoxin is reversible after cessation of textile work is unknown.

OBJECTIVES

To investigate changes in lung function and respiratory symptoms after cessation of textile work and to determine whether past exposure to cotton dust and endotoxin or smoking history modify the associations.

METHODS

We performed a prospective cohort study consisting of 447 cotton textile workers exposed to cotton dust and 472 unexposed silk textile workers, with a 25-year follow-up. Spirometry testing and respiratory questionnaires were conducted at 5-year intervals. Generalized estimated equations were used to model the average 5-year change in FEV(1) and odds ratios of respiratory symptom prevalence.

MEASUREMENTS AND MAIN RESULTS

Years since cessation of textile work was positively associated with 11.3 ml/yr and 5.6 ml/yr gains in 5-year FEV(1) change for cotton and silk workers, respectively. Among male cotton workers, smokers gained more FEV(1) per year after cessation of exposure than did nonsmokers, and the risk of symptoms of chronic bronchitis and byssinosis was larger for smoking than for nonsmoking male cotton workers.

CONCLUSIONS

Cessation of textile work was significantly associated with improvement in lung function and respiratory symptoms. The positive effect of work cessation was greater for cotton workers than for silk workers. For cotton workers, the improvement in lung function loss after cessation of textile work was greater among smokers, but no differences were observed for silk workers.

Effect of smoking on lung function, respiratory symptoms and respiratory diseases amongst HIV-positive subjects: a cross-sectional study

Background

Smoking prevalence in human immunodeficiency virus (HIV) positive subjects is about three times of that in the general population. However, whether the extremely high smoking prevalence in HIV-positive subjects affects their lung function is unclear, particularly whether smoking decreases lung function more in HIV-positive subjects, compared to the general population. We conducted this study to determine the association between smoking and lung function, respiratory symptoms and diseases amongst HIV-positive subjects.

Results

Of 120 enrolled HIV-positive subjects, 119 had an acceptable spirogram. Ninety-four (79%) subjects were men, and 96 (81%) were white. Mean (standard deviation [SD]) age was 43.4 (8.4) years. Mean (SD) of forced expiratory volume in one second (FEV₁) percent of age, gender, race and height predicted value (%FEV₁) was 93.1% (15.7%). Seventy-five (63%) subjects had smoked 24.0 (18.0) pack-years. For every ten pack-years of smoking increment, %FEV₁ decreased by 2.1% (95% confidence interval [CI]: -3.6%, -0.6%), after controlling for gender, race and restrictive lung function (R² = 0.210). The loss of %FEV₁ in our subjects was comparable to the general population. Compared to non-smokers, current smokers had higher odds of cough, sputum or breathlessness, after adjusting for highly active anti-retroviral therapy (HAART) use, odds ratio OR = 4.9 (95% CI: 2.0, 11.8). However respiratory symptom presence was similar between non-smokers and former smokers, OR = 1.0 (95% CI: 0.3, 2.8). All four cases of COPD (chronic obstructive pulmonary disease) had smoked. Four of ten cases of restrictive lung disease had smoked (p = 0.170), and three of five asthmatic subjects had smoked (p = 1.000).

Conclusions

Cumulative cigarette consumption was associated with worse lung function; however the loss of %FEV₁ did not accelerate in HIV-positive population compared to the general population. Current smokers had higher odds of respiratory symptoms than non-smokers, while former smokers had the same odds of respiratory symptoms as non-smokers. Cigarette consumption was likely associated with more COPD cases in HIV-positive population; however more participants and longer follow up would be needed to estimate the effect of smoking on COPD development. Effective smoking cessation strategies are required for HIV-positive subjects.

Excessive longitudinal FEV1 decline and risks to future health: a case-control study

BACKGROUND

Accelerated loss of forced expiratory volume in 1 s (FEV(1)) in an individual is considered an indicator of developing lung disease.

METHODS

We investigated longitudinal FEV(1) slopes, calculated by simple linear regression, and adverse health outcomes after 10-30 years, among 1,428 chemical plant workers. Cases were defined by FEV(1) slopes below 5th percentile values for the cohort. Cases were matched with controls (107 pairs) for race, gender, smoking status, year of birth, age, height, and calendar year at first test. Matched pair statistics were used for comparisons.

RESULTS

Cases had a higher proportion, compared to controls, of diagnosis of COPD or emphysema (17.8% vs. 1.9%, P = 0.0002), medication use for respiratory diseases (24.3% vs. 4.7%, P < 0.0001), dyspnea (15% vs. 3.7%, P = 0.0042), and wheezing or rhonchi on examination (10.3% vs. 1.9%, P = 0.0225).

CONCLUSIONS

Chemical plant workers who experienced accelerated FEV(1) declines experienced four to nine times as many adverse health conditions over 10-30 years.

Decline in FEV1in Relation to Incident Chronic Obstructive Pulmonary Disease in a Cohort with Respiratory Symptoms

Data on the relationship between decline in lung function and development of COPD are sparse. We assessed the decline in FEV1 during 10 years among subjects with respiratory symptoms by two different methods and evaluated risk factors for decline and its relation to incident Chronic Obstructive Pulmonary Disease, COPD. A cross-sectional postal questionnaire was in 1986 sent to 6610 subjects of three age strata. All subjects reporting respiratory symptoms were invited to a structured interview and spirometry. A follow-up survey was performed 10 years later, and totally 1109 subjects performed spirometry in both 1986 and 1996. COPD was defined according to the ATS/ERS standards (FEV1/FVC < or =0.70). The decline in FEV1 was 39 ml/year in men vs. 28 ml/year in women, p = < 0.001 (-1.53 vs. -0.12 change in percent of predicted normal value over 10 years (pp), p = 0.023), among smokers 39 vs. non-smokers 28 ml/year, p < 0.001 (-3.30 vs. 0.69 pp, p < 0.001), in subjects with chronic productive cough 36 vs. not 32 ml/year, p = 0.044 (-2.00 vs. -0.02 pp, p = 0.002). Incident cases of moderate COPD (n = 83) had a decline of 62 ml/year (-12.6 pp) and 22.9% of them had a decline > 90 ml/year (-27.8 pp over 10 years). Gender-specific analysis revealed that smoking was a stronger risk factor in women than in men, while higher age was a significant risk factor in men only. In conclusion, decline in FEV1 was associated with age, smoking, and chronic productive cough, but the risk factor pattern was gender-dependent. Among incident cases of COPD the decline was steeper and close to a quarter had a rapid decline.

Gender and respiratory findings in workers occupationally exposed to organic aerosols: a meta analysis of 12 cross-sectional studies

BACKGROUND

Gender related differences in respiratory disease have been documented. The aim of this study was to investigate gender related differences in respiratory findings by occupation. We analyzed data from 12 of our previously published studies.

METHODS

Three thousand and eleven (3011) workers employed in "organic dust" industries (1379 female and 1632 male) were studied. A control group of 806 workers not exposed to any kind of dust were also investigated (male = 419, female = 387). Acute and chronic respiratory symptoms and lung function were measured. The weighted average method and the Mantel-Haentszel method were used to calculate the odds ratios of symptoms. Hedge's unbiased estimations were used to measure lung function differences between men and women.

RESULTS

There were high prevalences of acute and chronic respiratory symptoms in all the "dusty" studied groups compared to controls. Significantly less chronic cough, chronic phlegm as well as chronic bronchitis were found among women than among men after the adjustments for smoking, age and duration of employment. Upper respiratory tract symptoms by contrast were more frequent in women than in men in these groups. Significant gender related lung function differences occurred in the textile industry but not in the food processing industry or among farmers.

CONCLUSION

The results of this study suggest that in industries processing organic compounds there are gender differences in respiratory symptoms and lung function in exposed workers. Whether these findings represent true physiologic gender differences, gender specific workplace exposures or other undefined gender variables not defined in this study cannot be determined. These data do not suggest that special limitations for women are warranted for respiratory health reasons in these industries, but the issue of upper respiratory irritation and disease warrants further study.