Prevalence and incidence of COPD in smokers and non-smokers: the Rotterdam Study

Imbalanced and Unchecked: The Role of Metal Dyshomeostasis in Driving COPD Progression

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory condition characterized by persistent inflammation and oxidative stress, which ultimately leads to progressive restriction of airflow. Extensive research findings have cogently suggested that the dysregulation of essential transition metal ions, notably iron, copper, and zinc, stands as a critical nexus in the perpetuation of inflammatory processes and oxidative damage within the lungs of COPD patients. Unraveling the intricate interplay between metal homeostasis, oxidative stress, and inflammatory signaling is of paramount importance in unraveling the intricacies of COPD pathogenesis. This comprehensive review aims to examine the current literature on the sources, regulation, and mechanisms by which metal dyshomeostasis contributes to COPD progression. We specifically focus on iron, copper, and zinc, given their well-characterized roles in orchestrating cytokine production, immune cell function, antioxidant depletion, and matrix remodeling. Despite the limited number of clinical trials investigating metal modulation in COPD, the advent of emerging methodologies tailored to monitor metal fluxes and gauge responses to chelation and supplementation hold great promise in unlocking the potential of metal-based interventions. We conclude that targeted restoration of metal homeostasis represents a promising frontier for ameliorating pathological processes driving COPD progression.

Impact of electronic cigarettes (e-cigs) and heat-not-burn/heated tobacco products (HnB/HTP) on asthma and chronic obstructive pulmonary disease: a viewpoint of the Italian Society of Internal Medicine

The association of cigarette smoking with several severe and very severe diseases (oncological, cardiovascular, respiratory) which have dramatic epidemiological, medical, and financial impact, is a well-known public threat. Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent diseases in Italy, posing significant public health challenges. Tobacco smoking, a primary risk factor for COPD and a common asthma trigger, remains a critical preventable public health issue. While universally acknowledged that quitting smoking drastically reduces the risk of smoking-related health issues, a significant portion of smokers and patients find quitting challenging or undesirable, hence a need for new ways to deal with it. A worth considering alternative might be the switch to electronic cigarettes (e-cig), and heat-not-burn/heated tobacco products (HnB/HTP). Emerging evidence suggests potential benefits in asthma and COPD management when transitioning from traditional smoking to e-cigs or HnB devices. However, the effectiveness of these products in facilitating smoking cessation is still debated, alongside concerns about their role in promoting smoking initiation among non-smokers. Internists are among the physicians who most frequently assist patients with smoking-related diseases, and in this perspective they cannot avoid paying attention to the progressive diffusion of smoking products alternative to the traditional cigarette, and to the controversies with respect to their use. In this context, the Italian Society of Internal Medicine, also recognizing a growing need for clarity for healthcare providers, has undertaken a comprehensive analysis of existing literature to offer an informed perspective on the health impact of e-cigs and HnB/HTP on asthma and COPD.

The impact of airborne particulate matter-based pollution on the cellular and molecular mechanisms in chronic obstructive pulmonary disease (COPD)

Inhalation of particulate matter (PM), one of the many components of air pollution, is associated with the development and exacerbation of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD). COPD is one of the leading causes of global mortality and morbidity, with a paucity of therapeutic options and a significant contributor to global health expenditure. This review aims to provide a mechanistic understanding of the cellular and molecular pathways that lead to the development of COPD following chronic PM exposure. Our review describes how the inhalation of PM can lead to lung parenchymal destruction and cellular senescence due to chronic pulmonary inflammation and oxidative stress. Following inhalation of PM, significant increases in a range of pro-inflammatory cytokines, mediated by the nuclear factor kappa B pathway are reported. This review also highlights how the inhalation of PM can lead to deleterious chronic oxidative stress persisting in the lung post-exposure. Furthermore, our work summarises how PM inhalation can lead to airway remodelling, with increases in pro-fibrotic cytokines and collagen deposition, typical of COPD. This paper also accentuates the interconnection and possible synergism between the pathophysiological mechanisms leading to COPD. Our work emphasises the serious health consequences of PM exposure on respiratory health. Elucidation of the cellular and molecular mechanisms can provide insight into possible therapeutic options. Finally, this review should serve as a stark reminder of the need for genuine action on air pollution to decrease the associated health burden on our growing global population.

Prevalence, mortality and risk factors for self-reported COPD among smokers and never smokers, NHANES 1999-2018

INTRODUCTION

Cigarette smoke is the main risk factor for chronic obstructive pulmonary disease (COPD), but 25% to 50% of cases occur in non-smokers. In the US, limited recent national data compare COPD prevalence between smokers and never smokers. Furthermore, our study seeks to explore the prevalence and mortality of self-reported COPD among smokers (including current smokers and ex-smokers) and never smokers in the US from 1999 to 2018, and to identify the risk factors and differences.

METHODS

This cross-sectional analysis used data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. Age-standardized prevalence of self-reported COPD among current smokers, ex-smokers, and never smokers was calculated using sample weights and 2010 US Census estimates. Risk factors were evaluated through weighted logistic regression models. Subsequently, participants who enrolled in the study cohort were followed until 31 December 2019, to determine all-cause mortality rates.

RESULTS

Between 1999 and 2018, the weighted prevalence of COPD among current smokers, ex-smokers, and never smokers in the U.S. was 12.6%, 9.6%, and 4.1%, respectively. The mortality rates observed were 21.1% among current smokers with COPD, 29% among ex-smokers with COPD, and 12% among never smokers with COPD. Over this period, among the general population in the U.S., the proportion of current smokers has declined, the proportion of never smokers has increased, and the proportion of ex-smokers has remained relatively stable. From 1999 to 2018, COPD prevalence rose from 13.7% to 21.9% among current smokers, stayed at 10.1% among ex-smokers, and dropped from 4.9% to 3.3% among never smokers. Independent risk factors for COPD across all groups included being female, older, and lower income. In particular, US citizens and non-Hispanic Whites (among ex-smokers and never smokers) were at higher risk compared to their counterparts.

CONCLUSIONS

The prevalence and all-cause mortality of COPD among current smokers and ex-smokers remain elevated. Although the prevalence of COPD among never smokers is gradually declining, it continues to be significant, thereby maintaining a substantial burden of disease. Furthermore, common independent risk factors for COPD across current smokers, ex-smokers, and never smokers include female gender, advanced age, lower income, and deviations from normal body weight whether overweight or underweight.

Revisiting the Clinical Interpretation of CT-Measured Pulmonary Artery-to-Aorta Ratio-The Rotterdam Study

RATIONALE

The pulmonary artery (PA) diameter-to-aorta ratio (PA:A) ratio is a novel marker in cardiovascular imaging for detecting pulmonary hypertension. However, we question the effect of the varying aorta diameter on the ratio, which complicates the interpretation of the PA:A ratio.

OBJECTIVE

Investigate the variability of the PA:A ratio by examining the correlation between PA:A ratio and aorta diameter and by comparing the associations of the PA diameter, aorta diameters, and PA:A ratio.

METHODS

We included 2197 participants from the Rotterdam Study who underwent non-contrast multidetector computed tomography to measure the PA and aorta diameters. Pearson correlation coefficient was calculated between the PA:A ratio and aorta diameter. Multiple linear regression analyses were performed to compare the determinants of the individual diameters and PA:A ratio.

RESULTS

We found a statistically significant correlation between the PA:A ratio and aorta diameter (r = -0.38, p < 0.001). The PA diameter was statistically significantly associated with, height, weight, diastolic blood pressure, blood pressure medication, prevalence of atrial fibrillation, prevalence of heart failure, and prevalence of stroke (p < 0.05). Except for blood pressure medication, the PA:A ratio had similar determinants compared to the PA diameter but was also statistically significantly associated with sex, and systolic blood pressure (p < 0.05), which were statistically significantly associated with the aorta diameter (p < 0.05).

CONCLUSION

The PA:A ratio should not be interpreted without taking into account the variability of the individual components (PA and aorta diameter) according to the anthropomorphic and clinical characteristics.

Obtaining the Most Accurate, Explainable Model for Predicting Chronic Obstructive Pulmonary Disease: Triangulation of Multiple Linear Regression and Machine Learning Methods

BACKGROUND

Lung disease is a severe problem in the United States. Despite the decreasing rates of cigarette smoking, chronic obstructive pulmonary disease (COPD) continues to be a health burden in the United States. In this paper, we focus on COPD in the United States from 2016 to 2019.

OBJECTIVE

We gathered a diverse set of non-personally identifiable information from public data sources to better understand and predict COPD rates at the core-based statistical area (CBSA) level in the United States. Our objective was to compare linear models with machine learning models to obtain the most accurate and interpretable model of COPD.

METHODS

We integrated non-personally identifiable information from multiple Centers for Disease Control and Prevention sources and used them to analyze COPD with different types of methods. We included cigarette smoking, a well-known contributing factor, and race/ethnicity because health disparities among different races and ethnicities in the United States are also well known. The models also included the air quality index, education, employment, and economic variables. We fitted models with both multiple linear regression and machine learning methods.

RESULTS

The most accurate multiple linear regression model has variance explained of 81.1%, mean absolute error of 0.591, and symmetric mean absolute percentage error of 9.666. The most accurate machine learning model has variance explained of 85.7%, mean absolute error of 0.456, and symmetric mean absolute percentage error of 6.956. Overall, cigarette smoking and household income are the strongest predictor variables. Moderately strong predictors include education level and unemployment level, as well as American Indian or Alaska Native, Black, and Hispanic population percentages, all measured at the CBSA level.

CONCLUSIONS

This research highlights the importance of using diverse data sources as well as multiple methods to understand and predict COPD. The most accurate model was a gradient boosted tree, which captured nonlinearities in a model whose accuracy is superior to the best multiple linear regression. Our interpretable models suggest ways that individual predictor variables can be used in tailored interventions aimed at decreasing COPD rates in specific demographic and ethnographic communities. Gaps in understanding the health impacts of poor air quality, particularly in relation to climate change, suggest a need for further research to design interventions and improve public health.

Lung function measurements in the Greenlandic Inuit population: results from the Greenlandic health survey 2017-2019

Background

Little is known about lung function in Inuit. The aim of this study was to describe lung function and the prevalence of obstructive and restrictive lung disease among Inuit in Greenland.

Methods

During the 2017-2019 Health Survey, spirometry, with forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio in liters (L), and percent of predicted value (pred%) were recorded according to Global Lung function Initiative standard reference values (GLI). Smoking history was obtained. Obstructive spirometry was defined as FEV1/FVC <70%. Restrictive spirometry was proposed by FVC < 80% and FEV1/FVC >90%.

Results

Based on validated spirometries, 795/2084 persons were included in this cross-sectional, descriptive study. Of those, 54.6% were current- and 27.7% former smokers. In Inuit, normal lung function was higher than predicted GLI (FEV1 107.2 pred%/FVC 113.5 pred%). In total, 106 (13.3%) were found to have an obstructive lung function measurement and 11 (1.4%) had a restrictive pattern. Among current smokers, the prevalence of obstructive lung function was 16.4%. An accelerated decline in lung function was observed > 50 years old (y.o), compared to <50 y.o.

Conclusion

This study indicates that Inuit has higher absolute lung function values than standard GLI, despite the large proportion of smokers, which indicate a need for Inuit reference values in the daily clinical praxis. The high prevalence of obstructive lung function and rapid decline in lung function indicates the need for fucus on health issues that may affect lung health in Greenland.

Care pathways versus usual care for chronic obstructive pulmonary disease (COPD)

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the effects of care pathways (CPs) compared to usual care/no CPs for people with chronic obstructive pulmonary disease (COPD).

The challenges of recruiting never-smokers with chronic obstructive pulmonary disease from the large population-based Swedish CArdiopulmonary bioImage study (SCAPIS) cohort

Background

A substantial proportion of individuals with COPD have never smoked, and it is implied to be more common than previously anticipated but poorly studied.

Aim

To describe the process of recruitment of never-smokers with COPD from a population-based cohort (n = 30 154).

Methods

We recruited never-smokers with COPD, aged 50-75 years, from six University Hospitals, based on: 1) post broncho-dilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) < 0.70 and 2) FEV1 50-100% of predicted value and 3) being never-smokers (self-reported). In total 862 SCAPIS participants were identified, of which 652 were reachable and agreed to a first screening by telephone. Altogether 128 (20%) were excluded due to previous smoking or declined participation. We also applied a lower limit of normal (LLN) of FEV1/FVC (z-score<-1.64) according to the Global Lung Initiative to ensure a stricter definition of airflow obstruction.

Results

Data on respiratory symptoms, health status, and medical history were collected from 492 individuals, since 32 were excluded at a second data review (declined or previous smoking), prior to the first visit. Due to not matching the required lung function criteria at a second spirometry, an additional 334 (68%) were excluded. These exclusions were by reason of: FEV1/FVC ≥0.7 (49%), FEV1 > 100% of predicted (26%) or z-score ≥ -1,64 (24%). Finally, 154 never-smokers with COPD were included: 56 (36%) women, (mean) age 60 years, FEV1 84% of predicted, FEV1/FVC: 0.6, z-score: -2.2, Oxygen saturation: 97% and BMI: 26.8 kg/m2.

Conclusions

The challenges of a recruitment process of never-smokers with COPD were shown, including the importance of correct spirometry testing and strict inclusion criteria. Our findings highlight the importance of repeated spirometry assessments for improved accuracy in diagnosing COPD.

New markers in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a global healthcare and socioeconomic burden, is a multifaceted respiratory disorder that results in substantial decline in health status and life quality. Acute exacerbations of the disease contribute significantly to increased morbidity and mortality. Consequently, the identification of reliable and effective biomarkers for rapid diagnosis, prediction, and prognosis of exacerbations is imperative. In addition, biomarkers play a crucial role in monitoring responses to therapeutic interventions and exploring innovative treatment strategies. Although established markers such as CRP, fibrinogen and neutrophil count are routinely used, a universal marker is lacking. Fortunately, an increasing number of studies based on next generation analytics have explored potential biomarkers in COPD. Here we review those advances and the need for standardized validation studies in the appropriate clinical setting.

Prevalence of Chronic Obstructive Pulmonary Disease and Its Associated Risk Factors in Yunnan Province, China: A Population Based Cross-Sectional Study

Purpose

Chronic obstructive pulmonary disease (COPD) is a significant disease impacting health and quality of life. Yunnan Province, a major tobacco producer, lacks comprehensive COPD studies. The purpose of this study is to describe the epidemic situation of COPD in Yunnan province and explore its influencing factors.

Methods

This study is a cross-sectional research conducted in a representative sample of adults aged 20 and older from 13 prefectures and cities in Yunnan Province, China. COPD was diagnosed using post-bronchodilator pulmonary function tests. Demographics were analyzed with descriptive statistics. The influencing factors of COPD were examined by using the multivariate logistic regression models.

Results

Our study found that high-risk individuals for COPD accounted for 20.30% of the screened population aged 20 and above, with a COPD prevalence of 27.18% among this high-risk group. Male had a higher prevalence (33.01%) than did female (16.35%; p<0.001 for sex difference). Additionally, the proportion of severe and extremely severe COPD cases in Yunnan Province was higher than the national average and other provinces. After considering the potential confounding variables, male (OR=2.291, 95% CI: 1.584-3.313), age (OR=1.501, 95% CI: 1.338-1.685), underweight (OR=1.747, 95% CI: 1.225-2.491), previous smoking (OR=1.712, 95% CI: 1.182-2.478), passive smoking (OR=1.444, 95% CI: 1.159-1.800), and a history of respiratory system diseases in childhood (OR=2.010, 95% CI: 1.346-3.001) were significantly associated with an increased risk of COPD. Conversely, being overweight (OR=0.636, 95% CI: 0.489-0.828), and residing in high-altitude counties (OR=0.445, 95% CI: 0.263-0.754) were negatively correlated with the risk of COPD.

Conclusion

There is significant prevalence of COPD (27.18%) among high-risk population aged 20 and above in Yunnan Province, China. Apart from male, smoking, BMI and other known risk factors for COPD. We found that high-altitude residence had a lower prevalence of COPD. There is no significant difference in COPD prevalence between Han and ethnic minority populations.

Proposed Etiotypes for Chronic Obstructive Pulmonary Disease: Controversial Issues

The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) revised the definition of chronic obstructive pulmonary disease (COPD) to broadly include a variety of etiologies. A new taxonomy, composed of etiotypes, aims to highlight the heterogeneity in causes and pathogenesis of COPD, allowing more personalized management strategies and emphasizing the need for targeted research to understand and manage COPD better. However, controversy arises with including some diseases under the umbrella term of COPD, as their clinical presentations and treatments differ from classical COPD, which is smoking-related. COPD due to infection (COPD-I) and COPD due to environmental exposure (COPD-P) are classifications within the new taxonomy. Some disease entities in these categories show distinct clinical features and may not benefit from conventional COPD treatments, raising questions about their classification as COPD subtypes. There is also controversy regarding whether bronchiectasis with airflow limitations should be classified as an etiotype of COPD. This article discusses controversial issues associated with the proposed etiotypes for COPD in terms of COPD-I, COPD-P, and bronchiectasis. While the updated COPD definition by GOLD 2023 is a major step towards recognizing the disease's complexity, it also raises questions about the classification of related respiratory conditions. This highlights the need for further research to improve our understanding and approach to COPD management.

Mitochondrial network dynamics in pulmonary disease: Bridging the gap between inflammation, oxidative stress, and bioenergetics

Once thought of in terms of bioenergetics, mitochondria are now widely accepted as both the orchestrator of cellular health and the gatekeeper of cell death. The pulmonary disease field has performed extensive efforts to explore the role of mitochondria in regulating inflammation, cellular metabolism, apoptosis, and oxidative stress. However, a critical component of these processes needs to be more studied: mitochondrial network dynamics. Mitochondria morphologically change in response to their environment to regulate these processes through fusion, fission, and mitophagy. This allows mitochondria to adapt their function to respond to cellular requirements, a critical component in maintaining cellular homeostasis. For that reason, mitochondrial network dynamics can be considered a bridge that brings multiple cellular processes together, revealing a potential pathway for therapeutic intervention. In this review, we discuss the critical modulators of mitochondrial dynamics and how they are affected in pulmonary diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), acute lung injury (ALI), and pulmonary arterial hypertension (PAH). A dysregulated mitochondrial network plays a crucial role in lung disease pathobiology, and aberrant fission/fusion/mitophagy pathways are druggable processes that warrant further exploration. Thus, we also discuss the candidates for lung disease therapeutics that regulate mitochondrial network dynamics.

Haemodynamic compensations for exercise tissue oxygenation in early stages of COPD: an integrated cardiorespiratory assessment study

BACKGROUND

Cardiovascular comorbidities are increasingly being recognised in early stages of chronic obstructive pulmonary disease (COPD) yet complete cardiorespiratory functional assessments of individuals with mild COPD or presenting with COPD risk factors are lacking. This paper reports on the effectiveness of the cardiocirculatory-limb muscles oxygen delivery and utilisation axis in smokers exhibiting no, or mild to moderate degrees of airflow obstruction using standardised cardiopulmonary exercise testing (CPET).

METHODS

Post-bronchodilator spirometry was used to classify participants as 'ever smokers without' (n=88), with 'mild' (n=63) or 'mild-moderate' COPD (n=56). All underwent CPET with continuous concurrent monitoring of oxygen uptake (V'O2) and of bioimpedance cardiac output (Qc) enabling computation of arteriovenous differences (a-vO2). Mean values of Qc and a-vO2 were mapped across set ranges of V'O2 and Qc isolines to allow for meaningful group comparisons, at same metabolic and circulatory requirements.

RESULTS

Peak exercise capacity was significantly reduced in the 'mild-moderate COPD' as compared with the two other groups who showed similar pulmonary function and exercise capacity. Self-reported cardiovascular and skeletal muscle comorbidities were not different between groups, yet disease impact and exercise intolerance scores were three times higher in the 'mild-moderate COPD' compared with the other groups. Mapping of exercise Qc and a-vO2 also showed a leftward shift of values in this group, indicative of a deficit in peripheral O2 extraction even for submaximal exercise demands. Concurrent with lung hyperinflation, a distinctive blunting of exercise stroke volume expansion was also observed in this group.

CONCLUSION

Contrary to the traditional view that cardiovascular complications were the hallmark of advanced disease, this study of early COPD spectrum showed a reduced exercise O2 delivery and utilisation in individuals meeting spirometry criteria for stage II COPD. These findings reinforce the preventive clinical management approach to preserve peripheral muscle circulatory and oxidative capacities.

COPD in Never-Smokers: BOLD Australia Study

Purpose

Tobacco smoking is the major risk factor for COPD, and it is common for other risk factors in never-smokers to be overlooked. We examined the prevalence of COPD among never-smokers in Australia and identified associated risk factors.

Methods

We used data from the Australia Burden of Obstructive Lung Disease (BOLD) study, a cross-section of people aged ≥40 years from six sites. Participants completed interviews and post-bronchodilator spirometry. COPD was primarily defined as an FEV1/FVC ratio <0.70 and secondarily as the ratio less than the lower limit of normal (LLN).

Results

The prevalence of COPD in the 1656 never-smokers who completed the study was 10.5% (95% CI: 9.1-12.1%) [ratio

Conclusion

COPD was prevalent in this population of never-smokers aged 40 years and over. This finding highlights the significance of risk factors other than smoking in the development of COPD.

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Key Words

• BOLD
• LLN
• burden of obstructive lung disease
• lower limit of normal
• non-smokers
• prevalence
• spirometry

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MESH Headings

• Female
• Male
• Humans
• Adult
• Middle Aged
• Child
• Smokers
• Pulmonary Disease, Chronic Obstructive/diagnosis
• Pulmonary Disease, Chronic Obstructive/epidemiology
• Asthma
• Odds Ratio
• Australia/epidemiology

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Grants

• National Health and Medical Research Council (NHMRC) of Australia
• Thoracic Society of Australia and New Zealand
• Robert Pierce Grant-in-Aid for Indigenous Lung Health
• Air Liquide, AstraZeneca; GlaxoSmithKline; and Boehringer Ingelheim

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Affiliation(s)

Marsha A Ivey School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, 3004, Australia School of Medicine, Faculty of Medical Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago
Sheree M Smith School of Nursing and Midwifery, Campbelltown Campus, Western Sydney University, Penrith, NSW, 2751, Australia Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia
Geza Benke School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, 3004, Australia
Brett G Toelle Respiratory and Environmental Epidemiology Group, Woolcock Institute of Medical Research, Sydney, NSW, 2037, Australia Sydney Local Health District, Sydney, NSW, 2050, Australia
Michael L Hunter School of Population and Global Health, University of Western Australia, Perth, WA, 6009, Australia
Alan L James Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital and Medical School, University of Western Australia, Perth, WA, 6009, Australia
Graeme P Maguire Curtin Medical School, Curtin University, Perth, WA, 6102, Australia
Richard Wood-Baker School of Medicine, University of Tasmania, Hobart, TAS, 7000, Australia
David P Johns Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia
Guy B Marks Respiratory and Environmental Epidemiology Group, Woolcock Institute of Medical Research, Sydney, NSW, 2037, Australia School of Clinical Medicine, University of New South Wales, Sydney, NSW, 2052, Australia
Michael J Abramson School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, 3004, Australia

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CYP2A6 associates with respiratory disease risk and younger age of diagnosis: a phenome-wide association Mendelian Randomization study

CYP2A6, a genetically variable enzyme, inactivates nicotine, activates carcinogens, and metabolizes many pharmaceuticals. Variation in CYP2A6 influences smoking behaviors and tobacco-related disease risk. This phenome-wide association study examined associations between a reconstructed version of our weighted genetic risk score (wGRS) for CYP2A6 activity with diseases in the UK Biobank (N = 395 887). Causal effects of phenotypic CYP2A6 activity (measured as the nicotine metabolite ratio: 3'-hydroxycotinine/cotinine) on the phenome-wide significant (PWS) signals were then estimated in two-sample Mendelian Randomization using the wGRS as the instrument. Time-to-diagnosis age was compared between faster versus slower CYP2A6 metabolizers for the PWS signals in survival analyses. In the total sample, six PWS signals were identified: two lung cancers and four obstructive respiratory diseases PheCodes, where faster CYP2A6 activity was associated with greater disease risk (Ps < 1 × 10-6). A significant CYP2A6-by-smoking status interaction was found (Psinteraction < 0.05); in current smokers, the same six PWS signals were found as identified in the total group, whereas no PWS signals were found in former or never smokers. In the total sample and current smokers, CYP2A6 activity causal estimates on the six PWS signals were significant in Mendelian Randomization (Ps < 5 × 10-5). Additionally, faster CYP2A6 metabolizer status was associated with younger age of disease diagnosis for the six PWS signals (Ps < 5 × 10-4, in current smokers). These findings support a role for faster CYP2A6 activity as a causal risk factor for lung cancers and obstructive respiratory diseases among current smokers, and a younger onset of these diseases. This research utilized the UK Biobank Resource.

New Therapeutic Options in Pulmonal Diseases: Sphingolipids and Modulation of Sphingolipid Metabolism

Sphingolipids are crucial molecules in the respiratory airways. As in most other tissues and organs, in the lung sphingolipids play an essential role as structural constituents as they regulate barrier function and fluidity of cell membranes. A lung-specific feature is the occurrence of sphingolipids as minor structural components in the surfactant. However, sphingolipids are also key signaling molecules involved in airway cell signaling and their dynamical formation and metabolism are important for normal lung physiology. Dysregulation of sphingolipid metabolism and signaling is involved in altering lung tissue and initiates inflammatory processes promoting the pathogenesis of pulmonal diseases including cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), and asthma.In the present review, the important role of specific sphingolipid species in pulmonal diseases will be discussed. Only such an understanding opens up the possibility of developing new therapeutic strategies with the aim of correcting the imbalance in sphingolipid metabolism and signaling. Such delivery strategies have already been studied in animal models of these lung diseases, demonstrating that targeting the sphingolipid profile represents new therapeutic opportunities for lung disorders.

Systematic Review and Meta-Analysis of Psychological Distress and Acute Exacerbation of Chronic Obstructive Pulmonary Disease and Consequences

BACKGROUND

People with chronic obstructive pulmonary disease (COPD) occasionally develop acute exacerbation of COPD-a potentially fatal condition. Psychological distress was associated with acute exacerbation of COPD. However, the evidence on the effect of psychological distress on acute exacerbation of COPD remains unclear.

OBJECTIVE

The aim of this study was to explore the influence of psychological distress on acute exacerbation of COPD and its consequences.

METHODS

The current review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using three databases (PubMed, CINAHL, and PsyINFO) that were searched to identify relevant articles. Pooled risk ratios and 95% confidential interval were calculated from the included studies' data with random-effect methods to estimate the effect of psychological distress on acute exacerbation of COPD and its consequences.

RESULTS

Nineteen articles were included in the review. Most revealed that psychological distress was significantly associated with increased risk of acute exacerbation of COPD and its consequences. The meta-analyses showed that psychological distress increased risk of acute exacerbation of COPD, COPD-related hospitalization, and death.

CONCLUSION

Psychological distress had negative effects on acute exacerbation of COPD and its consequences. The results of the meta-analyses show that persons with COPD and psychological distress had a greater risk of acute exacerbation of COPD, hospitalization, and death.

A Macrophage-Related Gene Signature for Identifying COPD Based on Bioinformatics and ex vivo Experiments

Background

This study aims to investigate the association between immune cells and the development of COPD, while providing a new method for the diagnosis of COPD according to the changes in immune microenvironment.

Methods

In this study, the "CIBERSORT" algorithm was used to estimate the tissue infiltration of 22 types of immune cells in GSE20257 and GSE10006. The "limma" package was used for differentially expressed analysis. The key modules associated with vital immune cells were identified using WGCNA. GO and KEGG enrichment analysis revealed the biological functions of the candidate genes. Ultimately, a novel diagnostic prediction model was constructed via machine learning methods and multivariate logistic regression analysis based on GSE20257. Furthermore, we examined the stability of the model on one internal test set (GSE10006), three external test sets (GSE8545, GSE57148 and GSE76925), one single-cell transcriptome dataset (GSE167295), macrophages (THP-M cells) and lung tissue from COPD patients.

Results

M0 macrophages (AUC > 0.7 in GSE20257 and GSE10006) were considered as the most important immune cells through exploring the immune microenvironment landscapes in COPD patients and healthy controls. The differentially expressed genes from GSE20257 and GSE10006 were divided into six and five modules via WGCNA, respectively. The green module in GSE20257 (cor = 0.41, P < 0.001) and the brown module in GSE10006 (cor = 0.67, P < 0.001) were highly correlated with M0 macrophages and were selected as key modules. Forty-one intersected genes obtained from two modules were primarily involved in regulation of cytokine production, regulation of innate immune response, specific granule, phagosome, lysosome, ferroptosis, and other biological processes. On the basis of the candidate genetic markers further characterized via the "Boruta" and "LASSO" algorithm for COPD, a diagnostic model comprising CLEC5A, FTL and SLC2A3 was constructed, which could accurately distinguish COPD patients from healthy controls in multiple datasets. GSE20257 as the training set has an AUC of 0.916. The AUCs of the internal test set and three external test sets were 0.873, 0.932, 0.675 and 0.688, respectively. Single-cell sequencing analysis suggested that CLEC5A, FTL and SLC2A3 were expressed in macrophages from COPD patients. The expressions of CLEC5A, FTL and SLC2A3 were up-regulated in THP-M cells and lung tissue from COPD patients.

Conclusion

According to the variations of immune microenvironment in COPD patients, we constructed and validated a novel macrophage M0-associated diagnostic model with satisfactory predictive value. CLEC5A, FTL and SLC2A3 are expected to be promising targets of immunotherapy in COPD.

Prevalence of chronic obstructive pulmonary disease in Indian nonsmokers: a systematic review & meta-analysis

INTRODUCTION

Nonsmokers with chronic obstructive pulmonary disease (COPD) are neglected despite constituting half of all cases in studies from the developed world. Herein, we systematically reviewed the prevalence of COPD among nonsmokers in India.

CONTENT

We searched Embase, Scopus, and PubMed databases for studies examining the prevalence of COPD among nonsmokers in India. We used the Joanna Briggs Institute (JBI) checklist to assess included studies' quality. Meta-analysis was performed using random-effects model.

SUMMARY

Seven studies comprising 6,903 subjects were included. The quality of the studies ranged from 5/9 to 8/9. The prevalence of COPD varied between 1.6 and 26.6 %. Studies differed considerably in demographics and biomass exposure profiles of subjects. Among the four studies that enrolled both middle-aged and elderly Indian nonsmokers not screened based on biomass fuel exposure, the pooled prevalence of COPD was 3 % (95 % CI, 2-3 %; I2=50.52 %, p=0.11). The pooled prevalence of COPD among biomass fuel-exposed individuals was 10 % (95 % CI, 2-18 %; I2=98.8 %, p<0.001).

OUTLOOK

Limited evidence suggests a sizable burden of COPD among nonsmokers and biomass fuel-exposed individuals in India. More epidemiological studies of COPD in nonsmokers are needed from low and middle-income countries.

Advances in the investigation of the role of autophagy in the etiology of chronic obstructive pulmonary disease: A review

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory illness. It arises from emphysema and chronic bronchitis and is characterized by progressive and irreversible airflow limitation and chronic inflammation of the lungs, which eventually progresses to pulmonary hypertension, chronic pulmonary heart disease and respiratory failure. Autophagy is a highly conserved cellular homeostasis maintenance mechanism that involves the transport of damaged organelles and proteins to lysosomes for destruction. Dysregulation of autophagy is one of the pathogenic mechanisms of many diseases and is strongly associated with the development of COPD, although the precise mechanisms are unknown. In this paper, we focus on macroautophagy, a type of autophagy that has been thoroughly studied, and describe the characteristics, processes, regulatory pathways, and functions of autophagy, and discuss its relationship with COPD from the perspectives of inflammation, emphysema, mucus hypersecretion, cilia structure and function, airway remodeling, vascular remodeling, and bacterial infections, with a view to searching for the therapeutic targets of COPD from the perspective of autophagy, which is hoped to be helpful for the clinical treatment.

COPD Risk Factor Profiles in General Population and Referred Patients: Potential Etiotypes

Purpose

To identify the risk factors for chronic obstructive pulmonary disease (COPD) in view of potential etiotypes in a general population and referred COPD patients.

Patients and Methods

We performed a cross-sectional observational study utilizing two distinct datasets: a dataset of a general population including 2430 subjects with COPD from the Korea National Health and Nutrition Examination Survey (KNHANES) and another dataset of referral clinics including 579 patients with COPD from the Korean Obstructive Lung Disease (KOLD).

Results

The mean age of both groups was 67 years, and 71.2% and 93.8% were male in the COPD subjects from the KNHANES and the KOLD, respectively. The mean forced expiratory volume in 1 second of predicted value was 79.1% (KNHANES) and 55.4% (KOLD). The frequency of risk factors of cigarette smoking (C), infection (I), pollution (P), and asthma (A) was 54.6%, 9.4%, 10.7%, and 7.9%, respectively, in the KNHANES COPD subjects, and 88.4%, 26.6%, 41.6%, and 35.2%, respectively, in the KOLD COPD subjects. Risk factors were unidentified in 32.6% (KNHANES) and 3.1% (KOLD) of COPD subjects. Additionally, 14.1% and 66.2% of subjects with COPD had two or more risk factors in the KNHANES and KOLD, respectively.

Conclusion

The profiles of risk factors C, I, P, and A were identified and appeared to be different among the two COPD groups from a general population or referral clinics. In some of the COPD subjects, risk factors were not identified, so we should endeavour to find out unidentified COPD risk factors, especially in the general population.

The Impact of Pulmonary Rehabilitation on Mental Health and Quality of Life in Patients With Chronic Obstructive Pulmonary Disease (COPD): A Narrative Review

Chronic obstructive pulmonary disease (COPD) is a complex, prevalent, debilitating, and degenerative disease that affects a large population, and the treatment options for the patients are limited. Although progress has been made in COPD pathogenesis, etiology, and management, there is still an unmet need to develop novel therapies. COPD management has recently seen a focus on a multidisciplinary pulmonary rehabilitation approach to help patients manage the disease better. This review primarily focuses on the role of pulmonary rehabilitation as a novel therapeutic strategy for treating and managing COPD, which is known to decrease patients' quality of life. Disease management and the beneficial effects of pulmonary rehabilitation in COPD are discussed. Subsequently, different methods that are employed in pulmonary rehabilitation are examined, including oxygen therapy, exercise, meditation, and education, emphasizing how they can help patients better manage COPD. Pathophysiology and the effect of pulmonary rehabilitation on the cellular level, such as the release of perforins and Th1 and Th17 cytokines, are also explored. The link between exercise and meditation during pulmonary rehabilitation therapy, which promotes repairing affected organs, is emphasized. Future perspectives on personalized medicine and its use in conjunction with pulmonary rehabilitation are also outlined. In conclusion, pulmonary rehabilitation holds significant promise for the management of COPD by addressing the present limitations of treatment. However, further research is essential to overcome and optimize treatment strategies for COPD patients.

Cardiovascular Outcomes of α-Blockers vs 5-α Reductase Inhibitors for Benign Prostatic Hyperplasia

Importance

The most prescribed class of medications for benign prostatic hyperplasia (BPH) is α-blockers (ABs). However, the cardiovascular safety profile of these medications among patients with BPH is not well understood.

Objective

To compare the safety of ABs vs 5-α reductase inhibitors (5-ARIs) for risk of adverse cardiovascular outcomes.

Design, Setting, and Participants

This active comparator, new-user cohort study was conducted using insurance claims data from a 20% random sample of Medicare beneficiaries from 2007 to 2019 to evaluate the 1-year risk of adverse cardiovascular outcomes. Males aged 66 to 90 years were indexed into the cohort at new use of an AB or 5-ARI. Twelve months of continuous enrollment and at least 1 diagnosis code for BPH within 12 months prior to initiation were required. Data were analyzed from January 2007 through December 2019.

Exposures

Exposure was defined by a qualifying prescription fill for an AB or 5-ARI after at least 12 months without a prescription for these drug classes.

Main Outcomes and Measures

Follow-up began at a qualified refill for the study drug. Primary study outcomes were hospitalization for heart failure (HF), composite major adverse cardiovascular events (MACE; hospitalization for stroke, myocardial infarction, or death), composite MACE or hospitalization for HF, and death. Inverse probability of treatment and censoring-weighted 1-year risks, risk ratios (RRs), and risk differences (RDs) were estimated for each outcome.

Results

Among 189 868 older adult males, there were 163 829 patients initiating ABs (mean [SD] age, 74.6 [6.2] years; 579 American Indian or Alaska Native [0.4%], 5890 Asian or Pacific Islander [3.6%], 9179 Black [5.6%], 10 610 Hispanic [6.5%], and 133 510 non-Hispanic White [81.5%]) and 26 039 patients initiating 5-ARIs (mean [SD] age, 75.3 [6.4] years; 76 American Indian or Alaska Native [0.3%], 827 Asian or Pacific Islander [3.2%], 1339 Black [5.1%], 1656 Hispanic [6.4%], and 21 605 non-Hispanic White [83.0%]). ABs compared with 5-ARIs were associated with an increased 1-year risk of MACE (8.95% [95% CI, 8.81%-9.09%] vs 8.32% [95% CI, 7.92%-8.72%]; RR = 1.08 [95% CI, 1.02-1.13]; RD per 1000 individuals = 6.26 [95% CI, 2.15-10.37]), composite MACE and HF (RR = 1.07; [95% CI, 1.03-1.12]; RD per 1000 individuals = 7.40 [95% CI, 2.88-11.93 ]), and death (RR = 1.07; [95% CI, 1.01-1.14]; RD per 1000 individuals = 3.85 [95% CI, 0.40-7.29]). There was no difference in risk for HF hospitalization alone.

Conclusions and Relevance

These results suggest that ABs may be associated with an increased risk of adverse cardiovascular outcomes compared with 5-ARIs. If replicated with more detailed confounder data, these results may have important public health implications given these medications' widespread use.

A nested case-control study of the effects of dust exposure, smoking on COPD in coal workers

BACKGROUND

Chronic obstructive pulmonary disease (COPD) represents a prevalent ailment, progressively surging within the ranks of coal mine laborers. The current study endeavors to elucidate the effects of dust exposure and smoking on COPD incidence amongst coal mine workers, while concurrently devising preventive strategies for this affliction.

METHOD

A nested case-control study was conducted encompassing 1,416 participants aged ≥ 18 years, spanning the duration from (2017-2018) until 2020. A meticulous matching process yielded a cohort of 708 COPD patients, each paired with a control subject, forming a harmonious 1:1 ratio. Multiple logistic regression analysis was employed to scrutinize the associations between smoking, dust exposure with COPD among coal workers.

RESULTS

The COPD prevalence within the cohort of coal workers under investigation amounted to 22.66%, with an accompanying incidence density of 0.09/person-year. Following meticulous adjustment for confounding variables, it was discerned that cumulative dust exposure within the range of 47.19 ~ (OR: 1.90, 95% CI: 1.05, 3.44), 101.27 ~ (OR: 1.99, 95% CI: 1.17, 3.39), as well as smoking indices of 72 ~ (OR: 1.85, 95% CI: 1.19, 2.88), 145 ~ (OR: 1.74, 95% CI: 1.17, 2.61), 310 ~ (OR: 1.85, 95% CI: 1.23, 2.77) engender an escalated vulnerability to COPD among coal workers. Furthermore, interaction analysis discerned an absence of both multiplicative and additive interactions between dust exposure, smoking, and COPD occurrence amidst coal workers.

CONCLUSION

Dust exposure and smoking were unequivocally identified as precipitating risk factors for COPD incidence within the population of coal workers, albeit devoid of any discernible interaction between these two causal agents.

Extracellular vesicles from subjects with COPD modulate cancer initiating cells phenotype through HIF-1α shuttling

Chronic obstructive pulmonary disease (COPD) is a risk factor for lung cancer development. COPD induces activation of hypoxia-induced signaling, causing remodeling of surrounding microenvironmental cells also modulating the release and cargo of their extracellular vesicles (EVs). We aimed to evaluate the potential role of circulating EVs from COPD subjects in lung cancer onset. Plasma-EVs were isolated by ultracentrifugation from heavy smoker volunteers with (COPD-EVs) or without (heavy smoker-EVs, HS-EV) COPD and characterized following MISEV guidelines. Immortalized human bronchial epithelial cells (CDK4, hTERT-HBEC3-KT), genetically modified with different oncogenic alterations commonly found in lung cancer (sh-p53, KRASV12), were used to test plasma-EVs pro-tumorigenic activity in vitro. COPD-EVs mainly derived from immune and endothelial cells. COPD-EVs selectively increased the subset of CD133+CXCR4+ metastasis initiating cells (MICs) in HBEC-sh-p53-KRASV12high cells and stimulated 3D growth, migration/invasion, and acquisition of mesenchymal traits. These effects were not observed in HBEC cells bearing single oncogenic mutation (sh-p53 or KRASV12). Mechanistically, hypoxia-inducible factor 1-alpha (HIF-1α) transferred from COPD-EVs triggers CXCR4 pathway activation that in turn mediates MICs expansion and acquisition of pro-tumorigenic effects. Indeed, HIF-1α inhibition or CXCR4 silencing prevented the acquisition of malignant traits induced by COPD-EVs alone. Hypoxia recapitulates the effects observed with COPD-EVs in HBEC-sh-p53-KRASV12high cells. Notably, higher levels of HIF-1α were observed in EVs from COPD subjects who subsequently developed cancer compared to those who remained cancer-free. Our findings support a role of COPD-EVs to promote the expansion of MICs in premalignant epithelial cells through HIF-1α-CXCR4 axis activation thereby potentially sustaining lung cancer progression.

Perceptions of the effectiveness of non-pharmacological management of respiratory disorders among CRD patients

Chronic respiratory diseases (CRDs) are among the leading cause of mortality worldwide. While pharmacological approaches are commonly used to manage symptoms, non-pharmacological management of CRDs is considered crucial in preventing disease progression and improving patient self-efficacy. To describe the perceived effectiveness of non-pharmacological management of CRDs among CRD patients and determine whether the CRD patients perceptions of the effectiveness of non-pharmacological management are associated with their demographic characteristics. An analytic cross-sectional study design was utilized. The non-pharmacological management practices of CRD patients and their perception of the effectiveness of these therapeutic measures were assessed using a researcher-developed questionnaire. Data collection took place in primary healthcare centers in Al Ahsa, Saudi Arabia from October 2021 to March 2022. The proportion of CRD patients who perceived that non-pharmacological interventions were effective was computed. Binary logistic regression was performed to determine the association between the demographic characteristics of the respondents and their perception of the effectiveness of non-pharmacological management. Among the 390 respondents, 42% perceived that non-pharmacological measures were effective. Half of the respondents believed that smoking cessation, influenza vaccination, improving physical activity, and nutrition support helped alleviate CRD symptoms, while less than half of the respondents considered pulmonary rehabilitation, educational programs, and oxygen therapy effective measures to control symptoms. Women were found to be 3.24 times more likely to perceive non-pharmacological interventions as effective (P < .0000) compared to men. Those with university-level education were 66.6% less likely to consider non-pharmacological interventions to be effective (P < .0000) than those who completed preuniversity-level education. Age and marital status did not significantly influence perceptions of effectiveness. Differences in the perceptions of the effectiveness of various non-pharmacological measures to alleviate CRD symptoms existed among the CRD patients of Al Ahsa. The perception of effectiveness was significantly associated with the patient's gender and educational attainment.

Association of Exposure to Biomass Fuels with Occurrence of Chronic Obstructive Pulmonary Disease in Rural Western China: A Real-World Nested Case-Control Study

Background

This study investigated the potential contribution of biomass fuels exposure to the occurrence of chronic obstructive pulmonary disease (COPD) in rural areas of western China.

Methods

We analyzed data collected between October 2017 and October 2018 from a nested case-control study of individuals at least 40 years old in the general population in Mianyang City, Sichuan Province, China. Demographic information was collected using a custom-designed questionnaire, and lung function was measured using spirometry. We used multivariate logistic regression to explore the possible relationship between biomass fuels exposure and COPD, as well as between other potential risk factors and COPD. Bayes' theorem was used to estimate weights for different COPD risk factors.

Results

COPD was newly diagnosed in 500 of the 11398 adults surveyed, corresponding to an incidence of 4.39%. Individuals who were exposed to biomass fuels were at a significantly greater risk of developing COPD than those not exposed (OR 2.58, 95% CI 2.23-3.05). In subgroup analysis, exposure to biomass fuels increased the risk of COPD in men by 1.71 times (95% CI 1.09-2.68) and in women by 2.88 times (95% CI 2.01-3.48), in never-smokers by 2.18 times. Bayesian weights for COPD risk factors were highest for poor kitchen ventilation (W=31.13%) and biomass fuels exposure (W=18.08%).

Conclusion

Our data indicate that rural Chinese who are exposed to biomass fuels during cooking or heating are at greater risk of developing COPD. Efforts should be made to strengthen the construction of clean energy infrastructure, so as to reduce the use of biomass fuels and thereby help prevent COPD.

Immunology in COPD and the use of combustible cigarettes and heated tobacco products

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic respiratory diseases, characterised by high morbidity and mortality. COPD is characterised by a progressive decline of lung function caused by chronic inflammatory reactions in the lung tissue due to continual exposure to harmful molecules by inhalation. As prevention plays a very important role in COPD, quitting smoking is the most important factor in reducing the decline in lung function. Unfortunately, many people are unable to break their nicotine addiction. This paper summarises current knowledge about combustible cigarettes (CSs) and alternative tobacco products such as heated tobacco products (HTPs) in COPD. The paper focuses on the immunological aspects of COPD and the influence of tobacco products on lung tissue immunology. There are differences in research results between HTPs and CSs in favour of HTPs. More long-term studies are needed to look at the effects of HTPs, especially in COPD. However, there is no doubt that it would be best for patients to give up their nicotine addiction completely.

Levels of Urinary Mercapturic Acids of Acrolein, Methacrolein, Crotonaldehyde, and Methyl Vinyl Ketone in Relationship to Chronic Obstructive Pulmonary Disease in Cigarette Smokers of the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)

Cigarette smoking is an established cause of chronic obstructive pulmonary disease (COPD). Numerous studies implicate acrolein, which occurs in relatively high concentrations in cigarette smoke and reacts readily with proteins, as one causative factor for COPD in smokers. Far less is known about the possible roles in COPD of the related α,β-unsaturated carbonyl compounds of cigarette smoke crotonaldehyde, methacrolein, and methyl vinyl ketone. In the study reported here, we analyzed mercapturic acids of these α,β-unsaturated compounds in the urine of 413 confirmed cigarette smokers in the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)─202 with COPD and 211 without COPD. The mercapturic acids analyzed were 3-hydroxypropyl mercapturic acid (3-HPMA) from acrolein, 3-hydroxy-1-methylpropyl mercapturic acid (HMPMA-1) from crotonaldehyde, 3-hydroxy-2-methylpropyl mercapturic acid (HMPMA-2) from methacrolein, and 3-hydroxy-3-methylpropyl mercapturic acid (HMPMA-3) from methyl vinyl ketone. In models adjusting for age, sex, race, pack years of tobacco use, and BMI, all four mercapturic acids were increased in individuals with COPD but not significantly. Stratified by the GOLD status, there were increased levels of the metabolites associated with GOLD 3-4 compared to that with GOLD 0, with the methacrolein metabolite HMPMA-2 reaching statistical significance (adjusted odds ratio 1.23 [95% CI: 1.00-1.53]). These results highlight the possible role of methacrolein, which has previously received little attention in this regard, as a causative factor in COPD in cigarette smokers.

The Possible Role of Food and Diet in the Quality of Life in Patients with COPD-A State-of-the-Art Review

Diet has been described as a modifiable risk factor for the development and progression of chronic diseases, and emerging evidence increasingly points to its preventive and therapeutic role in chronic obstructive pulmonary disease (COPD). While the relationship between the underlying disease and diet is natural in conditions such as metabolic disorders, obesity, diabetes, etc., the direct effect is not so evident in chronic obstructive pulmonary disease. Poor diet quality and the development of nutrient deficiencies in respiratory diseases, including COPD, can be associated with disease-specific factors such as the exacerbation of respiratory symptoms. These symptoms can be improved by dietary interventions, leading to positive changes in the pathogenesis of the disease and the quality of life of patients. Therefore, our aim was to review the latest randomized controlled trials (RCTs) of dietary interventions in chronic respiratory patients and describe their effects on respiratory function, physical activity, systemic inflammatory parameters, and quality of life. We conducted a literature search on dietary interventions for COPD patients in the PubMed, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials (CENTRAL) databases, focusing on publications from 1 July 2018 to 1 July 2023. We used specific keywords and MESH terms, focusing on RCTs. A total of 26 articles and 1811 COPD patients were included in this review. On the basis of our findings, dietary interventions, in particular components of the Mediterranean diet such as protein, omega-3 polyunsaturated fatty acids, and vegetables, appear to have beneficial effects in patients with chronic respiratory diseases, and their application is beneficial. However, long-term follow-up studies are still needed to examine the effects of dietary interventions in this patient population.

Can the Big Five personality traits predict ever chance and 7-year risk of clinically diagnosed chronic bronchitis in middle-aged and older adults?

OBJECTIVE

Chronic bronchitis refers to a chronic condition that is characterized by long-term inflammation of the bronchi. It is of great importance to understand the contributing risk factors for chronic bronchitis because it is associated with adverse outcomes such as healthcare burden and mortality. We aimed to understand if the personality traits could predict ever and the 7-year risk of clinically diagnosed chronic bronchitis in a large cohort of participants from the UK.

METHODS

We analyzed data from Understanding Society: the UK Household Longitudinal Study, which consists of 15,387 middle-aged or older participants for the cross-sectional analysis and 8783 middle-aged or older adults for the longitudinal analysis using two binary logistic regressions.

RESULTS

We found that Neuroticism (OR = 1.36, p < 0.001, 95% C.I. [1.23, 1.51]), Conscientiousness (OR = 0.87, p = 0.014, 95% C.I. [0.78, 0.97]), and Extraversion (OR = 1.15, p = 0.009, 95% C.I. [1.04, 1.29]) are related to a higher chance of ever clinically diagnosed chronic bronchitis. However, Agreeableness and Openness were not related to the chance of ever clinically diagnosed chronic bronchitis. Moreover, Conscientiousness (OR = 0.72, p = 0.012, 95% C.I. [0.55, 0.93]) was related to a lower risk of future clinical diagnosis of chronic bronchitis whereas Extraversion (OR = 1.35, p = 0.024, 95% C.I. [1.04, 1.76]) was associated with a higher risk of future chronic bronchitis. However, Neuroticism, Agreeableness, and Openness were not related to change of ever clinically diagnosed chronic bronchitis.

CONCLUSION

We showed that personality can identify people who are at greater risk of chronic bronchitis, which has translational utility for healthcare of middle-aged and older adults.

Understanding COPD Etiology, Pathophysiology, and Definition

COPD, one of the leading worldwide health problems, currently lacks truly disease-modifying medical therapies applicable to most patients. Developing such novel therapies has been hampered by the marked heterogeneity of phenotypes between individuals with COPD. Such heterogeneity suggests that, rather than a single cause (particularly just direct inhalation of tobacco products), development and progression of COPD likely involve both complex gene-by-environment interactions to multiple inhalational exposures and a variety of molecular pathways. However, there has been considerable recent progress toward understanding how specific pathological processes can lead to discrete COPD phenotypes, particularly that of small airways disease. Advances in imaging techniques that correlate to specific types of histological damage, and in the immunological mechanisms of lung damage in COPD, hold promise for development of personalized therapies. At the same time, there is growing recognition that the current diagnostic criteria for COPD, based solely on spirometry, exclude large numbers of individuals with very similar disease manifestations. This concise review summarizes current understanding of the etiology and pathophysiology of COPD and provides background explaining the increasing calls to expand the diagnostic criteria used to diagnose COPD and some challenges in doing so.

Cigarette smoke prevents M1 polarization of alveolar macrophages by suppressing NLRP3

Chronic obstructive pulmonary disease (COPD) is an inflammatory condition mainly caused by cigarette smoke (CS). Alveolar macrophages (AMs) contribute to its development, although the polarization of AMs is controversial. This study explored the polarization of AMs and mechanisms underlying their involvement in COPD. AM gene expression data from non-smokers, smokers, and COPD patients were downloaded from the GSE13896 and GSE130928 datasets. Macrophage polarization was evaluated by CIBERSORT and gene set enrichment analysis (GSEA). Polarization-related differentially expressed genes (DEGs) were identified in GSE46903. KEGG enrichment analysis and single sample GSEA were performed. M1 polarization levels were decreased in smokers and COPD patients, whereas M2 polarization did not change. In the GSE13896 and GSE130928 datasets, 27 and 19 M1-related DEGs, respectively, showed expression changes opposite to those in M1 macrophages in smokers and COPD patients compared with the control group. These M1-related DEGs were enriched in NOD-like receptor signaling pathway. Next, C57BL/6 mice were divided into control, lipopolysaccharide (LPS), CS, and LPS + CS groups, and cytokine levels in bronchoalveolar lavage fluid (BALF) and AM polarization were determined. The expression of macrophage polarization markers and NLRP3 was determined in AMs treated with CS extract (CSE), LPS, and an NLRP3 inhibitor. Cytokines levels and the percentage of M1 AMs in BALF were lower in the LPS + CS group than in the LPS group. Exposure to CSE downregulated the expression of M1 polarization markers and NLRP3 induced by LPS in AMs. The present results indicate that M1 polarization of AMs is repressed in smokers and COPD patients, and CS may inhibit LPS-induced M1 polarization of AMs by suppressing NLRP3.

Incidence of Interstitial Lung Abnormalities: The MESA Lung Study

The incidence of newly developed interstitial lung abnormalities (ILA) and fibrotic ILA have not been previously reported.Trained thoracic radiologists evaluated 13 944 cardiac CT scans for the presence of ILA in 6197 Multi-Ethnic Study of Atherosclerosis longitudinal cohort study participants >45 years of age from 2000 to 2012. 5% of the scans were re-read by the same or a different observer in a blinded fashion. After exclusion of participants with ILA at baseline, incidence rates and incidence rate ratios for ILA and fibrotic ILA were calculated.The intra-reader agreement of ILA was 92.0% (Gwet AC1=0.912, ICC=0.982) and the inter-reader agreement of ILA was 83.5% (Gwet AC1=0.814; ICC=0.969). Incidence of ILA and fibrotic ILA was estimated to be 13.1 cases/1000 person-years and 3.5/1000 person-years, respectively. In multivariable analyses, age (HR 1.06 (1.05, 1.08), p <0.001; HR 1.08 (1.06, 1.11), p <0.001), high attenuation area (HAA) at baseline (HR 1.05 (1.03, 1.07), p <0.001; HR 1.06 (1.02, 1.10), p=0.002), and the MUC5B promoter SNP (HR 1.73 (1.17, 2.56) p=0.01; HR 4.96 (2.68, 9.15), p <0.001) were associated with incident ILA and fibrotic ILA, respectively. Ever smoking (HR 2.31 (1.34, 3.96), p= 0.002) and an IPF polygenic risk score (HR 2.09 (1.61-2.71), p<0.001) were associated only with incident fibrotic ILA.Incident ILA and fibrotic ILA were estimated by review of cardiac imaging studies. These findings may lead to wider application of a screening tool for atherosclerosis to identify preclinical lung disease.

Investigation of time profile of FEV1 across the onset of potential COPD: a retrospective cohort study using medical checkup data in Japan

This study compared the time profile of FEV₁ after COPD diagnosis among rapid decliners, slow decliners, and sustainers in the year of COPD diagnosis. COPD subjects were identified from the annual medical checkup records of Hitachi, Ltd., employees in Japan (April 1998-March 2019). Subjects were categorized into 3 groups (rapid decliner [decrease of FEV₁ ≥ 63 mL/year], slow decliner [< 63 and ≥ 31 mL/year], and sustainer [< 31 mL/year]) for 5 years. The time profile of FEV₁ was compared using mixed-effects model for 5 years after diagnosis; risk factors of rapid decliner were detected using logistic model/gradient boosting decision tree. Of 1294 eligible subjects, 18.6%, 25.7%, and 55.7% were classified as rapid decliners, slow decliners, and sustainers, respectively. The annual rates of FEV₁ decline were similar 3 years before and until COPD diagnosis. The mean FEV₁ in rapid decliners was 2.82 ± 0.04 L in year 0 and 2.41 ± 0.05 L in year 5, and in sustainers, it was 2.67 ± 0.02 L and 2.72 ± 0.02 L (year 0, p = 0.0004). In conclusion, FEV₁ declined yearly before diagnosis and the time profiles of FEV₁ were different in the 3 groups after COPD diagnosis. Therefore, appropriate treatment of the 3 groups with regular lung function tests is necessary to follow FEV₁ decline after COPD onset.

The adjusted impact of different severities of acute exacerbations and medications on the risk of developing dementia in COPD patients

BACKGROUND

Although a relationship between chronic obstructive pulmonary disease (COPD) and dementia has been reported, the initial severity upon emergency department (ED) visits and the medications used have not been well evaluated as risk factors for increased dementia occurrence. We aimed to analyze the risks of dementia development over 5 years among patients with COPD compared to matched controls (primary) and the impact of different severities of acute exacerbations (AEs) of COPD and medications on the risk of dementia development among COPD patients (secondary).

METHOD

This study used the Taiwanese government deidentified health care database. We enrolled patients during the 10-year study period (January 1, 2000, to December 31, 2010), and each patient was followed up for 5 years. Once these patients received a diagnosis of dementia or died, they were no longer followed up. The study group included 51,318 patients who were diagnosed with COPD and 51,318 matched (in terms of age, sex, and the number of hospital visits) non-COPD patients from the remaining patients as the control group. Each patient was followed up for 5 years to analyze the risk of dementia with Cox regression analysis. Data on medications (antibiotics, bronchodilators, corticosteroids) and severity at the initial ED visit (ED treatment only, hospital admission, or ICU admission) were collected for both groups, as well as demographics and baseline comorbidities, which were considered confounding factors.

RESULTS

In the study and control groups, 1,025 (2.0%) and 423 (0.8%) patients suffered from dementia, respectively. The unadjusted HR for dementia was 2.51 (95% CI: 2.24-2.81) in the study group. Bronchodilator treatment was associated with the HRs, especially among those who received long-term (> 1 month) treatment (HR = 2.10, 95% CI: 1.91-2.45). Furthermore, among 3,451 AE of COPD patients who initially visited the ED, patients who required ICU admission (n = 164, 4.7%) had a higher risk of dementia occurrence (HR = 11.05, 95% CI: 7.77-15.71).

CONCLUSION

Bronchodilator administration might be associated with a decreased risk of dementia development. More importantly, patients who suffered AEs of COPD and initially visited the ED and required ICU admission had a higher risk of developing dementia.

Revealing EXPH5 as a potential diagnostic gene biomarker of the late stage of COPD based on machine learning analysis

Chronic obstructive pulmonary disease is a kind of chronic lung disease characterized by persistent air flow obstruction, which was the third leading cause of death in China. The incidence of COPD is steadily and increasing and has been a globally sever disease. Accordingly, it is urgently needed to explore how to diagnose and treat COPD timely. This study aims to find key genes to diagnose COPD as soon as possible to avoid COPD processing and analyze immune cell infiltration between COPD early stage and late stage. Two GEO datasets were merged as the merge data for analyses. 157 DEGs were used for GSEA analysis to find the pathway between COPD early stage and late stage. Above all, gene EXPH5 stood out from the screen as the most likely candidate diagnosis biomarker of COPD indicating the late-stage by least LASSO and SVM-RFE. ROC curves of EXPH5 were applied to represent the discriminatory ability through the area under the curve which is the gold standard to evaluate the accuracy of diagnosis and survival rate. The CIBERSORT algorithm was used to assess the distribution of tissue-infiltrating immune cells between two COPD stages. The diagnosis biomarker, gene EXPH5 had a positive correlation with NK cells resting; mast cell resting, eosinophils, and negative correlation with T cell gamma delta, macrophages M1, which underscore the role of gene and immune cell infiltration. To make results more reliable, we further analyzed the gene EXPH5 expression in single-cell transcriptome data and showed again that EXPH5 genes significantly downregulated in the late stage of COPD especially in the main lung cell types AT1 and AT2. In a word, our study identified genes EXPH5 as a marker gene, which adds to the knowledge for clinical diagnosis and pharmaceutical design of COPD.

Sputum-Rheology-Based Strategy for Guiding Azithromycin Prescription in COPD Patients with Frequent Exacerbations: A Randomized, Controlled Study (“COPD CARhE”)

(1) Background: We have previously shown that sputum rheology can discriminate between patients with COPD and other muco-obstructive lung diseases, and that it is correlated with mucin content and sputum eosinophilia. We now hypothesize that it could be a more-accurate guide than clinical evaluation for the prescription of azithromycin to prevent exacerbations of COPD and to reduce exposure to antibiotics; (2) Methods: “COPD CaRhe” is a multicentric, randomized, controlled trial comparing outcomes in two parallel arms (36 vs. 36 patients). Patients will be recruited in the university hospitals of Montpellier, Bordeaux, and Toulouse, in France, and they should have a diagnosis of COPD with frequent exacerbations (≥3/year). Enrollment will occur during a routine visit to a respiratory department, and follow-up visits will occur every 3 months for a period of 1 year. At each visit, a 3-month prescription of azithromycin will be provided to those patients who obtain a score of <70 on the Cough and Sputum Assessment Questionnaire (CASA-Q) or a critical stress score of σc > 39 on a rheological assessment of sputum, depending upon their randomization group. The primary outcome will be the number of exacerbations of COPD; (3) Discussion: By using sputum rheology, the COPD CaRhe study may provide clinicians with an objective biomarker to guide the prescription of azithromycin while reducing the cumulative exposure to macrolides.

Iron and mitochondria in the susceptibility, pathogenesis and progression of COPD

Chronic obstructive pulmonary disease (COPD) is a debilitating lung disease characterised by airflow limitation, chronic bronchitis, emphysema and airway remodelling. Cigarette smoke is considered the primary risk factor for the development of COPD; however, genetic factors, host responses and infection also play an important role. Accumulating evidence highlights a role for iron dyshomeostasis and cellular iron accumulation in the lung as a key contributing factor in the development and pathogenesis of COPD. Recent studies have also shown that mitochondria, the central players in cellular iron utilisation, are dysfunctional in respiratory cells in individuals with COPD, with alterations in mitochondrial bioenergetics and dynamics driving disease progression. Understanding the molecular mechanisms underlying the dysfunction of mitochondria and cellular iron metabolism in the lung may unveil potential novel investigational avenues and therapeutic targets to aid in the treatment of COPD.

The Effects and Pathogenesis of PM2.5 and Its Components on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), a heterogeneous disease, is the leading cause of death worldwide. In recent years, air pollution, especially particulate matter (PM), has been widely studied as a contributing factor to COPD. As an essential component of PM, PM2.5 is associated with COPD prevalence, morbidity, and acute exacerbations. However, the specific pathogenic mechanisms were still unclear and deserve further research. The diversity and complexity of PM2.5 components make it challenging to get its accurate effects and mechanisms for COPD. It has been determined that the most toxic PM2.5 components are metals, polycyclic aromatic hydrocarbons (PAHs), carbonaceous particles (CPs), and other organic compounds. PM2.5-induced cytokine release and oxidative stress are the main mechanisms reported leading to COPD. Nonnegligibly, the microorganism in PM 2.5 may directly cause mononuclear inflammation or break the microorganism balance contributing to the development and exacerbation of COPD. This review focuses on the pathophysiology and consequences of PM2.5 and its components on COPD.

Mechanisms of Lung Damage and Development of COPD Due to Household Biomass-Smoke Exposure: Inflammation, Oxidative Stress, MicroRNAs, and Gene Polymorphisms

Chronic exposure to indoor biomass smoke from the combustion of solid organic fuels is a major cause of disease burden worldwide. Almost 3 billion people use solid fuels such as wood, charcoal, and crop residues for indoor cooking and heating, accounting for approximately 50% of all households and 90% of rural households globally. Biomass smoke contains many hazardous pollutants, resulting in household air pollution (HAP) exposure that often exceeds international standards. Long-term biomass-smoke exposure is associated with Chronic Obstructive Pulmonary Disease (COPD) in adults, a leading cause of morbidity and mortality worldwide, chronic bronchitis, and other lung conditions. Biomass smoke-associated COPD differs from the best-known cigarette smoke-induced COPD in several aspects, such as a slower decline in lung function, greater airway involvement, and less emphysema, which suggests a different phenotype and pathophysiology. Despite the high burden of biomass-associated COPD, the molecular, genetic, and epigenetic mechanisms underlying its pathogenesis are poorly understood. This review describes the pathogenic mechanisms potentially involved in lung damage, the development of COPD associated with wood-derived smoke exposure, and the influence of genetic and epigenetic factors on the development of this disease.

Validation of Clinical COPD Phenotypes for Prognosis of Long-Term Mortality in Swedish and Dutch Cohorts

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease with variable mortality risk. The aim of our investigation was to validate a simple clinical algorithm for long-term mortality previously proposed by Burgel et al. in 2017. Subjects with COPD from two cohorts, the Swedish PRAXIS study (n = 784, mean age (standard deviation (SD)) 64.0 years (7.5), 42% males) and the Rotterdam Study (n = 735, mean age (SD) 72 years (9.2), 57% males), were included. Five clinical clusters were derived from baseline data on age, body mass index, dyspnoea grade, pulmonary function and comorbidity (cardiovascular disease/diabetes). Cox models were used to study associations with 9-year mortality. The distribution of clinical clusters (1-5) was 29%/45%/8%/6%/12% in the PRAXIS study and 23%/26%/36%/0%/15% in the Rotterdam Study. The cumulative proportion of deaths at the 9-year follow-up was highest in clusters 1 (65%) and 4 (72%), and lowest in cluster 5 (10%) in the PRAXIS study. In the Rotterdam Study, cluster 1 (44%) had the highest cumulative mortality and cluster 5 (5%) the lowest. Compared with cluster 5, the meta-analysed age- and sex-adjusted hazard ratio (95% confidence interval) for cluster 1 was 6.37 (3.94-10.32) and those for clusters 2 and 3 were 2.61 (1.58-4.32) and 3.06 (1.82-5.13), respectively. Burgel's clinical clusters can be used to predict long-term mortality risk. Clusters 1 and 4 are associated with the poorest prognosis, cluster 5 with the best prognosis and clusters 2 and 3 with intermediate prognosis in two independent cohorts from Sweden and the Netherlands.

Piperine Attenuates Cigarette Smoke-Induced Oxidative Stress, Lung Inflammation, and Epithelial-Mesenchymal Transition by Modulating the SIRT1/Nrf2 Axis

Piperine (PIP) is a major phytoconstituent in black pepper which is responsible for various pharmacological actions such as anti-inflammatory, antioxidant, and antitumor activity. To investigate the effects and mechanisms of PIP on cigarette smoke (CS)-induced lung pathology using both in-vitro and in-vivo models. BEAS-2B and A549 cells were exposed to CS extract (CSE) for 48 h; BALB/c mice were exposed to CS (9 cigarettes/day, 4 days) to induce features of airway disease. PIP at doses of (0.25, 1.25, and 6.25 µM, in vitro; 1 and 10 mg/kg, in vivo, i.n) and DEX (1 µM, in vitro; 1 mg/kg, in vivo, i.n) were used to assess cytotoxicity, oxidative stress, epithelial−mesenchymal transition (EMT), Sirtuin1 (SIRT1), inflammation-related cellular signaling, and lung function. PIP treatment protects cells from CSE-induced lung epithelial cell death. PIP treatment restores the epithelial marker (p < 0.05) and decreases the mesenchymal, inflammatory markers (p < 0.05) in both in vitro and in vivo models. The PIP treatment improves the altered lung function (p < 0.05) in mice induced by CS exposure. Mechanistically, PIP treatment modulates SIRT1 thereby reducing the inflammatory markers such as IL-1β, IL-6 and TNF-α (p < 0.05) and enhancing the epigenetic marker HDAC2 (p < 0.05) and antioxidant marker Nrf2 (p < 0.05) expressions. Thus, PIP alleviates pulmonary inflammation by modulating the SIRT1-mediated inflammatory cascade, inhibits EMT, and activates Nrf2 signaling.

Association Between Medication Adherence and Risk of COPD in Adult Asthma Patients: A Retrospective Cohort Study in Canada

Background

Poor adherence to prescribed asthma medications and risk of severe asthma exacerbations have been well established. However, the effects of changes in asthma medication compliance levels and subsequent risk of COPD is unknown and yet to be investigated. This study investigated the independent effect of medication adherence (MA) and asthma severity levels on the risk of COPD.

Methods

We used four linked administrative health databases from the Population data BC to identify asthma patients aged 18 years and older between January 1, 1998 and December 31, 1999 without diagnosis of COPD. The primary event was time-to-COPD diagnosis during the follow-up period (January 1, 2000 to December 31, 2018). The proportion of days covered (PDC) – was used as a surrogate measure for medication adherence (MA) assessed at optimal-level (≥ 0.80), Intermediate-level (0.50–0.79), and low-level (< 0.5) of adherence. A propensity adjusted analysis with Marginal Structural Cox (MSC) model was employed to estimate the adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI) for the effect of medication adherence and asthma severity over time.

Results

At cohort entry, the sample included 68,211 asthma patients with an overall mean age of 48.2 years. The 18-year incidence of COPD in asthma patients was 9.8 per 1000-persons year. In an inverse weighted propensity adjusted analysis of the MSC model, higher MA levels were significantly associated with decreased risk of COPD as follows: optimal-level (aHR: 0.19, 95% CI: 0.17–0.24); Intermediate-level (aHR: 0.20, 95% CI: 0.18, 0.23) compared to the low-level adherence group. A significant increase in COPD risk was observed in severe asthma patients with low medication adherence (aHR: 1.72, 95% CI: 1.52–1.93), independent of other patient factors.

Conclusion

Optimal (≥ 0.80) and intermediate adherence (0.5 to 0.79) levels were associated with reduced risk of COPD incidence over time. Interventions aimed at improving adherence to prescribed medications in adult asthma patients should be intensified to reduce their risk of COPD.

Estimating the Health Effect of Cigarette Smoking Duration in South Africa

This paper deepens the empirical analysis of the health effects of smoking by using the average treatment effect on the treated (ATET) and regression discontinuity design (RDD) to estimate the impact of smoking duration on health. The paper estimates the effect of cigarette smoking on health, that is, the exogenous increase in the probability of smoking-related ill health when individuals smoke up to a certain number of years. Using the National Income Dynamic survey (NIDS), the study finds that the probability of reporting poor health and/or suffering smoking-related diseases increases with the years of smoking. The magnitude of the effect is higher when smoking-related diseases rather than self-assessed health is considered but varies across time, socioeconomic status, and with different health outcomes. The effects are robust under several different parametric and non-parametric models. Using RDD, the paper also finds evidence of a discrete jump in poor health when individuals smoke up to 30 years. The results suggest that policies that are designed to reduce current levels of cigarette smoking may have a desirable impact and can create both current and future public health benefits.

Risk factors for post sternotomy wound complications across the patient journey: A systematised review of the literature

BACKGROUND

Around 36,000 cardiac operations are undertaken in the United Kingdom annually, with most procedures undertaken via median sternotomy. Wound complications occur in up to 8% of operations, with an associated mortality rate of around 47% in late or undetected cases.

OBJECTIVE

To undertake a systematised literature review to identify pre-operative, peri-operative and post-operative risk factors associated with sternal wound complications.

METHODS

Healthcare databases were searched for articles written in the English language and published between 2013 and 2021. Inclusion criteria were quantitative studies involving patients undergoing median sternotomy for cardiac surgery; sternal complications and risk factors.

RESULTS

1360 papers were identified, with 25 included in this review. Patient-related factors included: high BMI; diabetes; comorbidities; gender; age; presenting for surgery in a critical state; predictive risk scores; vascular disease; severe anaemia; medication such as steroids or α-blockers; and previous sternotomy. Peri-operative risk increased with specific types and combinations of surgical procedures. Sternal reopening was also associated with increased risk of sternal wound infection. Post-operative risk factors included a complicated recovery; the need for blood transfusions; respiratory complications; renal failure; non-diabetic hyperglycaemia; sternal asymmetry and sepsis.

CONCLUSION

Pre, peri and post-operative risk factors increase the risk of sternal wound complications in cardiac surgery. Generic risk assessment tools are primarily designed to provide mortality risk scores, with their ability to predict risk of wound infection questionable. Tools that incorporate factors throughout the operative journey are required to identify patients at risk of surgical wound infection.