This resource is in its pre-alpha development stage. Content is actively being curated and may be incomplete or subject to change.
0
Mappings
0
Definitions
0
Inheritance
8
Pathophysiology
0
Histopathology
11
Phenotypes
7
Genes
11
Treatments
2
Subtypes
0
Differentials
0
Datasets
0
Trials
🏷

Classifications

Harrison's Chapter
respiratory system disorder obstructive lung disease

Subtypes

2
Chronic Bronchitis
Inflammation of the bronchial tubes leading to increased mucus production and chronic cough.
Show evidence (3 references)
PMID:23204254 SUPPORT
"Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD)."
The article clearly states that Chronic Bronchitis (CB) is a subtype of COPD, characterized by inflammation of the bronchial tubes leading to increased mucus production and chronic cough.
PMID:27264777 SUPPORT
"Chronic obstructive pulmonary disease (COPD) is an umbrella term that covers many clinical subtypes with clearly different pulmonary and extra-pulmonary characteristics."
The article supports that COPD has multiple subtypes with differing characteristics, encompassing conditions like Chronic Bronchitis.
PMID:22753831 SUPPORT
"Chronic cough and sputum production: a clinical COPD phenotype?"
The article discusses the phenotype of COPD which includes chronic cough and sputum production, indicative of conditions like Chronic Bronchitis.
Emphysema
Damage to the alveoli resulting in shortness of breath and reduced surface area for gas exchange.
Show evidence (2 references)
PMID:33926668 SUPPORT
"Chronic obstructive pulmonary usually is subcategorized into 2 groups: chronic bronchitis and emphysema."
This reference reiterates the point that emphysema is a recognized subtype of COPD.
PMID:21178627 SUPPORT
"Latest studies further support the association of emphysema and COPD with coal dust exposure."
This confirms that emphysema is considered a subtype of COPD, further supporting the statement.

Pathophysiology

8
Airflow Limitation
Obstruction of airflow due to inflammation, mucus build-up, and remodeling of the airways.
Epithelial Cell link
inflammatory response link airway remodeling
bronchus link small airway
Show evidence (3 references)
PMID:23204254 SUPPORT
"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"
This study describes how mucus build-up and epithelial remodeling lead to airflow obstruction in COPD.
PMID:36108172 PARTIAL
"Phenotypic alterations in the lung epithelium have been widely implicated in chronic obstructive pulmonary disease (COPD) pathogenesis, but the precise mechanisms orchestrating this persistent inflammatory process remain unknown."
This study notes the involvement of epithelial cells in COPD but states that mechanisms remain unknown, partially supporting the role of epithelial cells in airflow obstruction.
PMID:38625125 SUPPORT
"Chronic exposure to environmental hazards causes airway epithelial dysfunction, primarily impaired physical barriers, immune dysfunction, and repair or regeneration. Impairment of airway epithelial function subsequently leads to exaggerated airway inflammation and remodeling, the main features..."
This study supports the statement by highlighting the role of epithelial dysfunction, inflammation, and remodeling in COPD pathophysiology.
Chronic Inflammation
Persistent irritation from inhaled substances like cigarette smoke leads to airway and alveolar inflammation.
Neutrophil link Macrophage link T-lymphocyte link
inflammatory response link neutrophil degranulation link
bronchus link alveolus of lung link
Show evidence (5 references)
PMID:17305517 SUPPORT
"Neutrophils and macrophages have been implicated in this process; they release proteolytic enzymes and generate oxidants, which cause tissue damage, as well as cytokines and chemokines, which can potentiate inflammation and trigger an immune response."
The literature describes the involvement of neutrophils, macrophages, and T-lymphocytes in the inflammatory process associated with COPD, supporting the notion of persistent irritation and chronic inflammation.
PMID:24507838 SUPPORT
"This inflammation is characterized by increased numbers of alveolar macrophages, neutrophils, and T lymphocytes, which are recruited from the circulation."
This article further substantiates the involvement of these cell types (neutrophils, macrophages, and T-lymphocytes) in the pathophysiology of COPD, linking them to chronic inflammation.
PMID:38035712 SUPPORT
"In this study, we found that neutrophilic phenotype (NP, 58.0%) was the most common airway inflammation phenotype in patients with COPD, followed by mixed granulocytic phenotype (MGP, 32.6%)."
The study indicates that neutrophils are predominant in COPD, supporting the statement about chronic inflammation.
+ 2 more references
Airway Remodeling
Structural changes in the airway due to chronic inflammation, including fibrosis and increased airway thickness.
Smooth Muscle Cell link
extracellular matrix organization link fibrosis
bronchus link small airway
Show evidence (3 references)
PMID:20500603 SUPPORT
"Moreover, airway remodelling occurs not only in asthma but also in several pulmonary disorders such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis and systemic sclerosis."
The statement aligns with the mentioned literature which notes airway remodeling as part of chronic obstructive pulmonary disease.
PMID:30257694 SUPPORT
"Multiple dysfunctions of ASM contribute to modulating airway responses to stimuli, remodeling, and fibrosis, as well as influence the compliance of lungs."
The statement is supported as this literature highlights the role of airway smooth muscle cells in airway remodeling and fibrosis in COPD.
PMID:15347849 SUPPORT
"Increases in airway smooth muscle mass occur in large airways of severe asthmatics and in small airways of patients with COPD."
The literature supports the statement by confirming the involvement of smooth muscle cells and structural changes in the airways in COPD.
Alveolar Destruction
Breakdown of alveolar walls, leading to reduced surface area for gas exchange and loss of lung elasticity.
Alveolar Macrophage link
proteolysis link extracellular matrix organization link
alveolus of lung link lung parenchyma link
Show evidence (4 references)
PMID:11993785 PARTIAL
"In the lung parenchyma, emphysema defined as alveolar destruction and airspace enlargement is present."
While the reference supports alveolar destruction as part of COPD's pathophysiology, it does not mention alveolar macrophages specifically.
PMID:29433833 PARTIAL
"In inflammatory lung diseases such as chronic obstructive pulmonary disease (COPD), despite their increased numbers, macrophages demonstrate significantly reduced phagocytic capacity of bacteria and apoptotic cells."
The macrophages' role in the pathophysiology of COPD is discussed, focusing on their reduced phagocytic capacity rather than direct alveolar destruction.
PMID:32493486 PARTIAL
"External insults like smoke and pollution can disturb surfactant homeostasis and result in either surfactant insufficiency or accumulation. But disruption of surfactant homeostasis is also observed in many chronic adult diseases, including chronic obstructive pulmonary disease (COPD)."
The role of alveolar macrophages (responsible for the degradation of surfactant) in the development of COPD is mentioned, but no direct link to alveolar destruction.
+ 1 more reference
Oxidative Stress and Mitochondrial Dysfunction
Cigarette smoke and pollutants trigger mitochondrial ROS production, impaired mitophagy, and reduced antioxidant defenses, amplifying inflammation.
airway epithelial cell link Alveolar Macrophage link
response to oxidative stress link mitochondrion organization link mitophagy link
bronchus link alveolus of lung link
Mucus Hypersecretion
Upregulation of MUC5AC and MUC5B, goblet cell hyperplasia, and impaired mucociliary clearance contribute to mucus plugging.
goblet cell link club cell link
mucus secretion link cilium movement link
bronchus link small airway
NLRP3 Inflammasome Activation
Mitochondrial ROS and particulate exposures activate NLRP3 inflammasome, leading to caspase-1 activation and IL-1β/IL-18 release.
Macrophage link airway epithelial cell link
NLRP3 inflammasome complex assembly link inflammatory response link
bronchus link alveolus of lung link
Cellular Senescence
Senescent epithelial, fibroblast, and immune cells exhibit senescence-associated secretory phenotype (SASP), promoting chronic inflammation and remodeling.
airway epithelial cell link fibroblast link
cellular senescence link inflammatory response link
lung link

Causal Graph

Referential integrity issues (1):
  • Target 'Progressive Respiratory Impairment' (from 'Airflow Limitation') not found in named elements
graph LR
    Respiratory_Failure["Respiratory Failure"]
    Exercise_Intolerance["Exercise Intolerance"]
    Hypoxemia["Hypoxemia"]
    Hypercapnia["Hypercapnia"]
    Progressive_Respiratory_Impairment["Progressive Respiratory Impairment"]
    Airflow_Limitation["Airflow Limitation"]
    Dyspnea["Dyspnea"]

    Airflow_Limitation -.-> Progressive_Respiratory_Impairment
    Dyspnea --> Exercise_Intolerance
    Respiratory_Failure --> Hypoxemia
    Respiratory_Failure --> Hypercapnia

    style Respiratory_Failure fill:#fef3c7
    style Exercise_Intolerance fill:#fef3c7
    style Hypoxemia fill:#fef3c7
    style Hypercapnia fill:#fef3c7
    style Progressive_Respiratory_Impairment fill:#fee2e2,stroke:#dc2626,stroke-dasharray: 5 5
    style Airflow_Limitation fill:#dbeafe
    style Dyspnea fill:#fef3c7

Phenotypes

11
Respiratory 7
Dyspnea VERY_FREQUENT Dyspnea (HP:0002094)
Sequelae: Exercise Intolerance
Show evidence (3 references)
PMID:28277858 SUPPORT
"Indeed, it is an important symptom in chronic obstructive pulmonary disease (COPD), where it is associated with limited physical activity, increased anxiety and depression, decreased health-related quality of life (HRQoL), and reduced survival."
The literature supports that dyspnea is a common symptom in COPD and is frequently observed in patients, confirming its categorization as a respiratory phenotype with diagnostic importance.
PMID:35698999 SUPPORT
"Dyspnoea and pain are symptoms of chronic obstructive pulmonary disease (COPD)... The pooled prevalence of pain and dyspnoea was 44% (95% confidence interval (CI) 35%-52%) and 91% (95% CI 87%-94%) respectively."
This study highlights the high prevalence of dyspnea in patients with COPD, further supporting its status as a very frequent respiratory phenotype.
PMID:34972922 SUPPORT
"Up to date research has shown a positive correlation between the elevated levels of some markers of EBC such as H2O2 and 8-isoprostane and dyspnea, while others present ambiguous results"
The correlation between dyspnea and COPD is reinforced by the positive association found with certain markers in exhaled breath condensate.
Chronic Cough VERY_FREQUENT Chronic cough (HP:0034315)
Often productive of mucus
Show evidence (2 references)
PMID:29881269 SUPPORT
"Compared with patients without chronic cough, those with chronic cough exhibited a lower forced expiratory volume in 1 second (% predicted) and diffusing capacity of the lungs for carbon monoxide (% predicted), more frequent AECOPD, more severe dyspnea, and worse QoL."
The study identifies chronic cough as a common and significant phenotype in COPD patients, indicating its very frequent occurrence and diagnostic importance.
PMID:31740261 SUPPORT
"COPD is now widely accepted as a heterogeneous condition with multiple phenotypes and endotypes. This review will discuss the old and new concepts for the different types of COPD phenotypes."
The statement mentions the heterogeneity of COPD with multiple phenotypes, which could include phenotypes like chronic cough.
Sputum Production VERY_FREQUENT Increased sputum production (HP:0033709)
Mucus is often difficult to expectorate
Show evidence (2 references)
PMID:22753831 SUPPORT
"Chronic cough and sputum production: a clinical COPD phenotype?"
The title of the article itself suggests that sputum production is recognized as a phenotype of COPD.
PMID:23204254 SUPPORT
"Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD)."
Chronic bronchitis, which involves overproduction and hypersecretion of mucus, is described as a common phenomenon in COPD, indicating sputum production is a frequent COPD phenotype.
Wheezing FREQUENT Wheezing (HP:0030828)
Due to airflow obstruction
Show evidence (3 references)
PMID:33302722 SUPPORT
"The clinical symptoms of this disease include progressive dyspnea, cough, expectoration, and wheezing, among others."
The abstract mentions wheezing as one of the clinical symptoms of Chronic Obstructive Pulmonary Disease (COPD).
PMID:11963614 SUPPORT
"Remember, all that wheezes is not asthma; therefore, providers in this case had to determine if the patient was suffering something such as anaphylaxis, asthma, bronchitis, pneumonia or even congestive heart failure (CHF)."
The abstract indicates that wheezing can be a symptom of various conditions, including COPD-related bronchospasm.
PMID:2404712 SUPPORT
"Increased airways reactivity is present in 15 to 70 percent of patients with chronic airflow obstruction."
The abstract discusses increased airway reactivity, which is related to wheezing, in patients with chronic airflow obstruction, including COPD.
Respiratory Failure OCCASIONAL Respiratory failure (HP:0002878)
Sequelae: Hypoxemia Hypercapnia
Show evidence (2 references)
PMID:14621114 REFUTE
"Respiratory failure is still an important complication of chronic obstructive pulmonary disease (COPD) and hospitalisation with an acute episode being a poor prognostic marker."
The reference indicates that respiratory failure is an important and common complication of COPD, not an occasional one.
PMID:38692758 REFUTE
"Hypoventilation is a complication that is not uncommon in chronic obstructive pulmonary disease and calls for both medical treatment of the underlying disease and, frequently, noninvasive ventilation either during exacerbations requiring hospitalization or in a chronic state in the patient at home."
The reference suggests that hypoventilation, which can lead to respiratory failure, is not uncommon in COPD.
Hypoxemia FREQUENT Hypoxemia (HP:0012418)
Hypercapnia FREQUENT Hypercapnia (HP:0012416)
Constitutional 2
Fatigue FREQUENT Fatigue (HP:0012378)
Show evidence (3 references)
PMID:33998496 SUPPORT
"Fatigue: A neglected symptom of COPD."
The title itself indicates that fatigue is a recognized symptom of COPD.
PMID:31729154 SUPPORT
"Fatigue is an important yet ignored symptom of chronic obstructive pulmonary disease (COPD)."
This reference acknowledges fatigue as an important symptom of COPD, supporting its frequent occurrence.
PMID:24874124 SUPPORT
"Symptoms in COPD do not solely arise from the degree of airflow obstruction as exercise limitation is compounded by the specific secondary manifestations of the disease including skeletal muscle impairment, osteoporosis, mood disturbance, anemia, and hormonal imbalance."
While this reference does not mention fatigue explicitly, it discusses systemic manifestations of COPD, implying the systemic nature of the disease.
Exercise Intolerance FREQUENT Exercise intolerance (HP:0003546)
Growth 1
Weight Loss OCCASIONAL Weight loss (HP:0001824)
More common in advanced disease
Show evidence (3 references)
PMID:12406664 SUPPORT
"Weight loss occurs frequently in patients with chronic obstructive pulmonary disease (COPD)."
The literature states that weight loss is a common phenomenon in COPD patients, which supports the statement that weight loss is a systemic issue in COPD, more common in advanced disease.
PMID:18415812 SUPPORT
"These include unintentional weight loss, skeletal muscle dysfunction, an increased risk of cardiovascular disease, osteoporosis, and depression, among others."
This reference mentions unintentional weight loss as one of the systemic effects of COPD, supporting the statement.
PMID:36922031 SUPPORT
"COPD patients with psychological (high anxiety and depression) and cachectic (underweight and osteoporotic) comorbidity have higher mortality and exacerbate more."
The mention of cachexia (underweight) as a comorbidity in COPD patients aligns with the statement about weight loss being more common in advanced disease.
Other 1
Barrel Chest OCCASIONAL
Due to hyperinflation of the lungs
Show evidence (3 references)
PMID:25159007 PARTIAL
"Lung hyperinflation is highly prevalent in patients with chronic obstructive pulmonary disease and occurs across the continuum of the disease."
The reference supports the association of lung hyperinflation with COPD but does not specifically mention 'Barrel Chest' or its frequency.
PMID:34972922 PARTIAL
"Attempts to connect the products of the analysis of the EBC with the clinical manifestations of COPD such as dyspnea are scarce."
The reference discusses the clinical manifestations of COPD but does not specifically mention 'Barrel Chest' or its frequency.
PMID:23204254 NO_EVIDENCE
"Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD)."
The reference discusses chronic bronchitis in COPD but does not mention 'Barrel Chest' or its frequency.
🧬

Genetic Associations

7
SERPINA1 (Alpha-1 antitrypsin deficiency is the most common genetic cause of COPD.)
Show evidence (3 references)
PMID:32800189 SUPPORT
"Alpha-1 antitrypsin deficiency (AATD) was the first genetic risk factor for chronic obstructive pulmonary disease (COPD) described."
The abstract clearly mentions that AATD is a genetic risk factor for COPD, supporting the statement.
PMID:35104244 SUPPORT
"Alpha-1 antitrypsin deficiency (AATD) is the most common genetic cause and risk factor for chronic obstructive pulmonary disease."
The text directly supports the statement by identifying AATD as a common genetic cause and risk factor for COPD.
PMID:36630963 SUPPORT
"Genetic variation in alpha-1 antitrypsin (AAT) causes AAT deficiency (AATD) through liver aggregation-associated gain-of-toxic pathology and/or insufficient AAT activity in the lung manifesting as chronic obstructive pulmonary disease (COPD)."
The abstract highlights that genetic variation in AAT leading to AATD manifests as COPD, thus supporting the statement.
MMP12 (Matrix metalloproteinase-12 contributes to emphysema development.)
NLRP3 (Inflammasome activation contributes to chronic inflammation.)
TNF (Tumor necrosis factor mediates systemic and airway inflammation.)
IL1B (Interleukin-1 beta drives inflammatory signaling.)
IL6 (Interleukin-6 contributes to systemic inflammation.)
NFE2L2 (Nrf2 transcription factor regulates antioxidant defense.)
💊

Treatments

11
Smoking Cessation MAXO:0000077
Stopping smoking to slow disease progression and improve outcomes.
Show evidence (4 references)
PMID:25496790 SUPPORT
"Stopping smoking reduces the risk of developing COPD and is an essential treatment for this inflammatory disease. Smoking cessation decreases the prevalence of respiratory symptoms, number of hospitalizations, and decline in FEV1, as well as exacerbation frequency and overall mortality."
The reference clearly states that smoking cessation is essential in reducing various harmful outcomes related to COPD.
PMID:19811377 SUPPORT
"Smoking cessation and lung volume reduction surgery would both qualify as disease-modifying interventions."
The reference identifies smoking cessation as a disease-modifying intervention, which indicates its importance in slowing disease progression and thus improving outcomes.
PMID:11935838 SUPPORT
"The most important intervention is smoking cessation."
The reference emphasizes that smoking cessation is the most important intervention to minimize the impact of COPD.
+ 1 more reference
Bronchodilators MAXO:0000058
Medications that relax muscles of the airways to improve airflow (e.g., beta-agonists, anticholinergics).
Show evidence (3 references)
PMID:29794201 SUPPORT
"Bronchodilator therapy can often decrease symptoms of air-flow obstruction by relaxing airway smooth muscle (bronchodilation), decreasing dyspnea, and improving quality of life."
The reference discusses how bronchodilator therapy relaxes airway smooth muscle, which improves airflow in obstructive lung diseases like COPD.
PMID:27576232 SUPPORT
"Long-acting beta2-agonists and long-acting muscarinic antagonists are first-line treatments for patients with persistently symptomatic COPD with an FEV1 of 80% or less of predicted."
This reference identifies bronchodilators, specifically long-acting beta2-agonists and muscarinic antagonists, as key treatments for COPD by improving airflow.
PMID:28757318 SUPPORT
"Combination long-acting inhaled bronchodilators are central to the management of patients with moderate to very severe chronic obstructive pulmonary disease."
This reference confirms that bronchodilators, such as long-acting beta2 agonists and long-acting muscarinic antagonists, are used to manage COPD symptoms by improving pulmonary function.
Inhaled Corticosteroids MAXO:0000312
Reduce airway inflammation and frequency of exacerbations.
Show evidence (4 references)
PMID:20102305 PARTIAL
"Short-term treatment with ICS improves lung function and quality of life; in addition, several studies with longer follow-up have shown less decline over time in quality of life, and fewer exacerbations. By contrast, long-term studies have been unable to show substantial improvement in the..."
While ICS do help reduce the frequency of exacerbations and improve quality of life, the evidence on their effectiveness in reducing airway inflammation specifically is more nuanced.
PMID:37348121 PARTIAL
"Current pharmacologic strategies, including first- and second-line therapies such as long-acting β2-agonists, long-acting muscarinic antagonists, inhaled corticosteroids, phosphodiesterase-4 inhibitors, and macrolides, provide relief to patients with COPD"
ICS are included in the treatment strategies, and while they help mitigate exacerbations, the snippet suggests that not all patients experience reduced airway inflammation.
PMID:29938633 SUPPORT
"The major alteration has been in the section concerning treatment with inhalation medication - now aiming at an easy stepwise up-titration of long-acting medicine as well as a guide of how to down-titrate inhaled corticosteroids."
The guideline update underscores the role of ICS in managing stable COPD, highlighting their long-term use for reducing symptoms and managing exacerbations.
+ 1 more reference
Phosphodiesterase-4 Inhibitors MAXO:0000058
Reduce inflammation and relax airways.
Show evidence (4 references)
PMID:15699784 SUPPORT
"Some of the selective PDE4 inhibitors have demonstrated in vitro and in vivo anti-inflammatory activity on cells commonly linked to airway inflammation in COPD, such as neutrophils."
The reference indicates that selective phosphodiesterase 4 inhibitors show anti-inflammatory activity, supporting the statement about reducing inflammation.
PMID:20649375 SUPPORT
"Roflumilast targets inflammatory processes in COPD, with beneficial effects on tobacco-induced lung inflammation, lung fibrosis and remodeling, mucociliary malfunction and oxidative stress."
Roflumilast, a PDE4 inhibitor, targets inflammatory processes, thus supporting the statement.
PMID:34731461 SUPPORT
"The orally administered PDE4 inhibitor roflumilast reduces exacerbation rates in the subgroup of chronic obstructive pulmonary disease patients with a history of exacerbations and the presence of chronic bronchitis, but can cause PDE4 related adverse effects due to systemic exposure."
This reference confirms the anti-inflammatory effect of PDE4 inhibitors which aligns with the statement.
+ 1 more reference
Oxygen Therapy MAXO:0000503
Long-term oxygen use for patients with severe chronic hypoxemia.
Show evidence (3 references)
PMID:24461631 SUPPORT
"This therapeutic intervention has been shown to increase survival in patients with chronic obstructive pulmonary disease (COPD) and respiratory failure."
The literature supports that long-term oxygen therapy (LTOT) is used to treat patients with COPD who have severe chronic hypoxemia.
PMID:37353334 SUPPORT
"Long-term oxygen therapy (LTOT) is a mainstay treatment for patients with severe resting hypoxemia secondary to chronic respiratory conditions including COPD."
This reference specifically mentions LTOT as a primary treatment for patients with severe chronic hypoxemia due to COPD.
PMID:19462352 SUPPORT
"Only smoking cessation and long term oxygen therapy (LTOT) improve survival in COPD."
This study confirms that LTOT is a treatment that improves survival in patients with severe COPD and chronic hypoxemia.
Pulmonary Rehabilitation MAXO:0000011
Exercise training, education, and support to improve quality of life and physical conditioning.
Show evidence (5 references)
PMID:29526182 SUPPORT
"PR is an effective and cost-effective therapeutic intervention that improves physical performance ability, shortness of breath, and the quality of life in patients with COPD."
The reference indicates that pulmonary rehabilitation (PR) improves physical performance, shortness of breath, and quality of life in COPD patients, aligning with the statement's description of treatments including exercise training, education, and support.
PMID:34338012 SUPPORT
"Exercise improves the physiological and psychological condition of people with chronic obstructive pulmonary disease and should be encouraged, with referral to a pulmonary rehabilitation service if available."
This reference supports the statement's claim by emphasizing the importance of exercise and recommending pulmonary rehabilitation to improve the quality of life and physical conditioning in COPD patients.
PMID:34955635 SUPPORT
"The combination of drug therapy with non-drug therapy such as pulmonary rehabilitation training has demonstrated a great potential in reducing the occurrence of complications and delaying the progression of COPD."
This reference supports the statement by highlighting the benefits of pulmonary rehabilitation training, specifically its potential to improve quality of life and physical conditioning in COPD patients.
+ 2 more references
Lung Volume Reduction Surgery MAXO:0000004
Surgical removal of damaged lung tissue for severe emphysema.
Show evidence (3 references)
PMID:22189668 SUPPORT
"Surgical approaches include lung transplantation and lung volume reduction and the latter has been shown to improve exercise tolerance, quality of life, and survival in highly selected patients with advanced emphysema."
The literature supports the use of lung volume reduction surgery as a treatment for severe emphysema in chronic obstructive pulmonary disease (COPD) patients.
PMID:33926668 SUPPORT
"As symptoms and lung function decline, treatment modalities, such as lung volume reduction surgery, have been used in individuals with chronic obstructive pulmonary disease and upper lobe predominant emphysema."
The literature indicates that lung volume reduction surgery is a treatment used for severe emphysema, a condition associated with COPD.
PMID:31145187 SUPPORT
"Mortality benefits to therapy have been demonstrated in only 2 therapeutic interventions to date: long-term use of daily supplemental oxygen and surgical lung volume reduction (LVRS) for upper-lobe-predominant disease in patients with a low baseline exercise capacity."
The statement is supported as the literature suggests that lung volume reduction surgery is an established treatment for upper-lobe-predominant, severe emphysema in COPD patients.
Lung Transplantation MAXO:0010039
Considered in end-stage COPD with severe impairment.
Show evidence (4 references)
PMID:17240617 SUPPORT
"Lung transplantation is a surgical option for patients who fail optimization of medical treatment for the severe symptoms that result from COPD."
This reference states that lung transplantation is a considered treatment option for patients with severe symptoms resulting from COPD.
PMID:31375190 SUPPORT
"End-stage congestive heart failure, chronic obstructive pulmonary disease...palliative principles can guide decision making and symptom management in these disease states."
The reference focuses on end-stage COPD and mentions lung transplantation as a consideration in managing the conditions of patients.
PMID:36050206 SUPPORT
"The International Thoracic Organ Transplant Registry...focus on lung transplant recipients with chronic obstructive pulmonary disease."
This source concentrates on lung transplantation for patients with COPD, in line with the statement's context of it being a treatment for end-stage COPD.
+ 1 more reference
Mucolytic Therapy MAXO:0000058
N-acetylcysteine and other mucolytics reduce mucus viscosity and may improve mucociliary clearance.
Macrolide Antibiotics MAXO:0000058
Long-term macrolide therapy reduces exacerbation frequency but raises antimicrobial resistance concerns.
Biologic Therapies MAXO:0000058
Precision biologics targeting Type 2 inflammation in eosinophilic COPD subsets.
🌍

Environmental Factors

3
Smoking
Primary risk factor for development and progression.
Show evidence (5 references)
PMID:30810540 SUPPORT
"Although cigarette smoking is the major risk factor, only 10-20% of smokers develop COPD."
This clearly identifies smoking as a major risk factor for COPD development.
PMID:31759959 SUPPORT
"The observation that COPD is an independent risk factor for cardiovascular disease (CVDs) comes from comparisons between smokers with COPD and smokers without COPD."
This snippet highlights the relationship between smoking, COPD, and other health issues, indirectly supporting smoking as a risk factor for COPD.
PMID:28933915 SUPPORT
"The epithelial lining of the airway forms the first barrier against environmental insults, such as inhaled cigarette smoke, which is the primary risk factor for the development of chronic obstructive pulmonary disease (COPD)."
Directly states that cigarette smoke is the primary risk factor for COPD development.
+ 2 more references
Air Pollution
Exposure to pollutants can exacerbate symptoms.
Show evidence (5 references)
PMID:33542053 SUPPORT
"Our findings suggest that, when considering total personal exposure to air pollutants, mainly the gaseous pollutants affect COPD patients' health."
This study found that exposure to various air pollutants adversely affects the health of COPD patients, supporting the idea that air pollution exacerbates COPD symptoms.
PMID:25673984 SUPPORT
"The major pathogenic factors causing disease include infection and inflammation, protease and antiprotease imbalance, and oxidative stress overwhelming antioxidant defenses."
This reference discusses environmental factors, including pollutants, that contribute to oxidative stress and inflammation in COPD, thus supporting the statement.
PMID:37068517 SUPPORT
"Harmful inhaled workplace exposures can contribute to the development of chronic obstructive pulmonary disease (COPD)."
This statement supports the environmental influence on COPD, including air pollutants, as a risk factor.
+ 2 more references
Occupational Dust and Chemicals
Long-term exposure increases risk.
Show evidence (5 references)
PMID:11964759 SUPPORT
"occupational exposure to dusts, chemicals and gases will be considered an established, or supported by good evidence, risk factor for chronic obstructive pulmonary disease"
The abstract confirms that occupational exposure to dusts, chemicals, and gases is a well-supported risk factor for chronic obstructive pulmonary disease.
PMID:20535848 SUPPORT
"Lung function loss associated with occupational dust exposure in metal smelting"
This study provides evidence of lung function loss due to occupational dust exposure, supporting the assertion that long-term exposure to such environmental factors increases the risk of chronic obstructive pulmonary disease.
PMID:23361196 SUPPORT
"Recent studies have recognized the contribution of workplace exposures to chronic lung diseases, in particular chronic obstructive pulmonary disease (COPD)"
The abstract discusses the recognized contribution of workplace exposures, including textile dust, to chronic obstructive pulmonary disease.
+ 2 more references
🔬

Biochemical Markers

2
Arterial Blood Gases (Altered)
Show evidence (4 references)
PMID:21812941 PARTIAL
"The aim of this study was to identify predictors of hypoxemia, hypercapnia and increased alveolar-arterial oxygen difference in COPD patients."
The study confirms that COPD patients may show hypoxemia and hypercapnia, but it focuses on the predictors rather than just the presence of these conditions.
PMID:34756790 SUPPORT
"Respiratory acidosis with hypoxia, hypercapnia, a compensatory metabolic response, and mild hyperfibrinolysis were probably related to the combined effect of nitrogen compounds and the inhaled toxic products of detonation."
The study discusses the occurrence of hypoxia and hypercapnia in specific exposure situations, including COPD contexts.
PMID:25119324 SUPPORT
"The prevalence of this sampling method has grown among health professionals, coupled with a growing demand for domiciliary oxygen therapy in the UK, in particular for those who have chronic obstructive pulmonary disease (COPD)."
While this does not directly confirm hypoxemia and hypercapnia, it suggests the necessity of oxygen therapy for COPD patients, implying altered arterial blood gases.
+ 1 more reference
C-Reactive Protein (CRP) (Elevated)
Context: General inflammation and exacerbations.
Show evidence (5 references)
PMID:23206444 SUPPORT
"Patients with COPD had higher serum CRP concentrations than healthy controls (WMD 4.72 mg/l, 95% CI 2.98, 6.47)."
This meta-analysis suggests that patients with stable COPD had higher serum CRP concentrations than healthy controls, indicating elevated CRP in general inflammation related to COPD.
PMID:24313775 SUPPORT
"These biomarkers include C-reactive protein, procalcitonin, and peripheral blood eosinophil count, which are readily available."
The study identifies CRP as an important biomarker in COPD exacerbations, indicating its elevation in such contexts.
PMID:24102428 SUPPORT
"Serum CRP levels were also significantly higher on D1 compared to D7 (p < 0.001)."
The findings that CRP levels are elevated at the onset of COPD exacerbations support the statement.
+ 2 more references
{ }

Source YAML

click to show
name: Chronic_Obstructive_Pulmonary_Disease
creation_date: '2025-12-04T16:57:31Z'
updated_date: '2026-02-17T21:53:14Z'
category: Complex
parents:
- Respiratory Disease
- Smoking-Related Disease
has_subtypes:
- name: Chronic Bronchitis
  description: Inflammation of the bronchial tubes leading to increased mucus
    production and chronic cough.
  evidence:
  - reference: PMID:23204254
    supports: SUPPORT
    snippet: Chronic bronchitis (CB) is a common but variable phenomenon in
      chronic obstructive pulmonary disease (COPD).
    explanation: The article clearly states that Chronic Bronchitis (CB) is a
      subtype of COPD, characterized by inflammation of the bronchial tubes
      leading to increased mucus production and chronic cough.
  - reference: PMID:27264777
    supports: SUPPORT
    snippet: Chronic obstructive pulmonary disease (COPD) is an umbrella term
      that covers many clinical subtypes with clearly different pulmonary and
      extra-pulmonary characteristics.
    explanation: The article supports that COPD has multiple subtypes with
      differing characteristics, encompassing conditions like Chronic
      Bronchitis.
  - reference: PMID:22753831
    supports: SUPPORT
    snippet: 'Chronic cough and sputum production: a clinical COPD phenotype?'
    explanation: The article discusses the phenotype of COPD which includes
      chronic cough and sputum production, indicative of conditions like Chronic
      Bronchitis.
- name: Emphysema
  description: Damage to the alveoli resulting in shortness of breath and
    reduced surface area for gas exchange.
  evidence:
  - reference: PMID:33926668
    supports: SUPPORT
    snippet: 'Chronic obstructive pulmonary usually is subcategorized into 2 groups:
      chronic bronchitis and emphysema.'
    explanation: This reference reiterates the point that emphysema is a
      recognized subtype of COPD.
  - reference: PMID:21178627
    supports: SUPPORT
    snippet: Latest studies further support the association of emphysema and
      COPD with coal dust exposure.
    explanation: This confirms that emphysema is considered a subtype of COPD,
      further supporting the statement.
prevalence:
- population: Global
  percentage: 11.7
  evidence:
  - reference: PMID:35261410
    supports: NO_EVIDENCE
    snippet: 'The estimated pooled prevalence of COPD was 11.1% (95% confidence interval,
      CI: 7.4-14.8%), using the Global Initiative for Chronic Obstructive Lung Disease
      fixed criteria and 8.0% (95% CI: 5.6-10.4%) using the lower limit of normal
      criteria.'
    explanation: The study provides prevalence data for specific regions (e.g.,
      South Asia) but does not mention a global prevalence rate of 11.7%.
  - reference: PMID:37461046
    supports: NO_EVIDENCE
    snippet: Though disease burden of silicosis has been on a decline in general
      from 1990 to 2019, which shows a promising prospect but cannot be ignored.
    explanation: This study focuses on the global incidence, prevalence, and
      disease burden of silicosis, not COPD.
progression:
- phase: Onset
  notes: Typically begins in individuals over the age of 40.
  evidence:
  - reference: PMID:26154786
    supports: PARTIAL
    snippet: Among 657 persons who had an FEV1 of less than 80% of the predicted
      value before 40 years of age, 174 (26%) had COPD after 22 years of
      observation, whereas among 2207 persons who had a baseline FEV1 of at
      least 80% of the predicted value before 40 years of age, 158 (7%) had COPD
      after 22 years of observation.
    explanation: The literature suggests that COPD can develop in individuals
      with low FEV1 before the age of 40. While this supports the idea that COPD
      typically begins in individuals over 40, it also indicates that it can
      start earlier in some cases.
  - reference: PMID:19934351
    supports: SUPPORT
    snippet: There is growing evidence of higher prevalence of chronic
      obstructive pulmonary disease (COPD) in the elderly. Age-associated
      changes in the structure and function of the lung may increase a
      pathogenetic susceptibility to COPD.
    explanation: This reference supports the statement that COPD typically
      begins in individuals over the age of 40, particularly due to
      age-associated changes in lung structure and function.
pathophysiology:
- name: Airflow Limitation
  description: Obstruction of airflow due to inflammation, mucus build-up, and
    remodeling of the airways.
  cell_types:
  - preferred_term: Epithelial Cell
    term:
      id: CL:0000066
      label: epithelial cell
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
  - preferred_term: airway remodeling
    description: Structural changes in airway architecture
  locations:
  - preferred_term: bronchus
    term:
      id: UBERON:0002185
      label: bronchus
  - preferred_term: small airway
    description: Terminal and respiratory bronchioles
  downstream:
  - target: Progressive Respiratory Impairment
    description: Chronic airway inflammation and remodeling lead to progressive
      airflow obstruction and respiratory decline.
    evidence:
    - reference: PMID:39046133
      supports: SUPPORT
      snippet: Chronic exposure to smoking and noxious particles or gases
        induces inflammation and remodeling, leading to airway obstruction and
        SAD, eventually resulting in complete airway loss.
      explanation: This 2024 review establishes that chronic inflammation and
        remodeling cause irreversible airflow limitation and progressive
        respiratory decline in COPD.
  evidence:
  - reference: PMID:23204254
    supports: SUPPORT
    snippet: 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
    explanation: This study describes how mucus build-up and epithelial
      remodeling lead to airflow obstruction in COPD.
  - reference: PMID:36108172
    supports: PARTIAL
    snippet: Phenotypic alterations in the lung epithelium have been widely
      implicated in chronic obstructive pulmonary disease (COPD) pathogenesis,
      but the precise mechanisms orchestrating this persistent inflammatory
      process remain unknown.
    explanation: This study notes the involvement of epithelial cells in COPD
      but states that mechanisms remain unknown, partially supporting the role
      of epithelial cells in airflow obstruction.
  - reference: PMID:38625125
    supports: SUPPORT
    snippet: Chronic exposure to environmental hazards causes airway epithelial
      dysfunction, primarily impaired physical barriers, immune dysfunction, and
      repair or regeneration. Impairment of airway epithelial function
      subsequently leads to exaggerated airway inflammation and remodeling, the
      main features of chronic obstructive pulmonary disease (COPD).
    explanation: This study supports the statement by highlighting the role of
      epithelial dysfunction, inflammation, and remodeling in COPD
      pathophysiology.
- name: Chronic Inflammation
  description: Persistent irritation from inhaled substances like cigarette
    smoke leads to airway and alveolar inflammation.
  cell_types:
  - preferred_term: Neutrophil
    term:
      id: CL:0000775
      label: neutrophil
  - preferred_term: Macrophage
    term:
      id: CL:0000235
      label: macrophage
  - preferred_term: T-lymphocyte
    term:
      id: CL:0000084
      label: T cell
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
  - preferred_term: neutrophil degranulation
    term:
      id: GO:0043312
      label: neutrophil degranulation
  locations:
  - preferred_term: bronchus
    term:
      id: UBERON:0002185
      label: bronchus
  - preferred_term: alveolus of lung
    term:
      id: UBERON:0002299
      label: alveolus of lung
  evidence:
  - reference: PMID:17305517
    supports: SUPPORT
    snippet: Neutrophils and macrophages have been implicated in this process;
      they release proteolytic enzymes and generate oxidants, which cause tissue
      damage, as well as cytokines and chemokines, which can potentiate
      inflammation and trigger an immune response.
    explanation: The literature describes the involvement of neutrophils,
      macrophages, and T-lymphocytes in the inflammatory process associated with
      COPD, supporting the notion of persistent irritation and chronic
      inflammation.
  - reference: PMID:24507838
    supports: SUPPORT
    snippet: This inflammation is characterized by increased numbers of alveolar
      macrophages, neutrophils, and T lymphocytes, which are recruited from the
      circulation.
    explanation: This article further substantiates the involvement of these
      cell types (neutrophils, macrophages, and T-lymphocytes) in the
      pathophysiology of COPD, linking them to chronic inflammation.
  - reference: PMID:38035712
    supports: SUPPORT
    snippet: In this study, we found that neutrophilic phenotype (NP, 58.0%) was
      the most common airway inflammation phenotype in patients with COPD,
      followed by mixed granulocytic phenotype (MGP, 32.6%).
    explanation: The study indicates that neutrophils are predominant in COPD,
      supporting the statement about chronic inflammation.
  - reference: PMID:38891820
    supports: SUPPORT
    snippet: Recent multiomics-based evidence suggests that the plasticity of
      alveolar macrophages contributes to the onset and progression of COPD
      through the coordinated modulation of numerous transcription factors.
    explanation: The article highlights the role of macrophages in the
      pathogenesis and progression of COPD, thus supporting the statement.
  - reference: PMID:11993785
    supports: PARTIAL
    snippet: The characteristic changes in the central airways include
      inflammatory cellular infiltration into the airway wall and mucous gland
      enlargement.
    explanation: This reference provides a broader overview of the pathological
      changes in COPD, mentioning inflammatory cells but not specifically
      detailing the involvement of neutrophils, macrophages, and T-lymphocytes.
- name: Airway Remodeling
  description: Structural changes in the airway due to chronic inflammation,
    including fibrosis and increased airway thickness.
  cell_types:
  - preferred_term: Smooth Muscle Cell
    term:
      id: CL:0000192
      label: smooth muscle cell
  biological_processes:
  - preferred_term: extracellular matrix organization
    term:
      id: GO:0030198
      label: extracellular matrix organization
  - preferred_term: fibrosis
    description: Excessive deposition of connective tissue
  locations:
  - preferred_term: bronchus
    term:
      id: UBERON:0002185
      label: bronchus
  - preferred_term: small airway
    description: Terminal and respiratory bronchioles
  evidence:
  - reference: PMID:20500603
    supports: SUPPORT
    snippet: Moreover, airway remodelling occurs not only in asthma but also in
      several pulmonary disorders such as chronic obstructive pulmonary disease,
      idiopathic pulmonary fibrosis and systemic sclerosis.
    explanation: The statement aligns with the mentioned literature which notes
      airway remodeling as part of chronic obstructive pulmonary disease.
  - reference: PMID:30257694
    supports: SUPPORT
    snippet: Multiple dysfunctions of ASM contribute to modulating airway
      responses to stimuli, remodeling, and fibrosis, as well as influence the
      compliance of lungs.
    explanation: The statement is supported as this literature highlights the
      role of airway smooth muscle cells in airway remodeling and fibrosis in
      COPD.
  - reference: PMID:15347849
    supports: SUPPORT
    snippet: Increases in airway smooth muscle mass occur in large airways of
      severe asthmatics and in small airways of patients with COPD.
    explanation: The literature supports the statement by confirming the
      involvement of smooth muscle cells and structural changes in the airways
      in COPD.
- name: Alveolar Destruction
  description: Breakdown of alveolar walls, leading to reduced surface area for
    gas exchange and loss of lung elasticity.
  cell_types:
  - preferred_term: Alveolar Macrophage
    term:
      id: CL:0000583
      label: alveolar macrophage
  biological_processes:
  - preferred_term: proteolysis
    term:
      id: GO:0006508
      label: proteolysis
  - preferred_term: extracellular matrix organization
    term:
      id: GO:0030198
      label: extracellular matrix organization
  locations:
  - preferred_term: alveolus of lung
    term:
      id: UBERON:0002299
      label: alveolus of lung
  - preferred_term: lung parenchyma
    term:
      id: UBERON:0008946
      label: lung parenchyma
  evidence:
  - reference: PMID:11993785
    supports: PARTIAL
    snippet: In the lung parenchyma, emphysema defined as alveolar destruction
      and airspace enlargement is present.
    explanation: While the reference supports alveolar destruction as part of
      COPD's pathophysiology, it does not mention alveolar macrophages
      specifically.
  - reference: PMID:29433833
    supports: PARTIAL
    snippet: In inflammatory lung diseases such as chronic obstructive pulmonary
      disease (COPD), despite their increased numbers, macrophages demonstrate
      significantly reduced phagocytic capacity of bacteria and apoptotic cells.
    explanation: The macrophages' role in the pathophysiology of COPD is
      discussed, focusing on their reduced phagocytic capacity rather than
      direct alveolar destruction.
  - reference: PMID:32493486
    supports: PARTIAL
    snippet: External insults like smoke and pollution can disturb surfactant
      homeostasis and result in either surfactant insufficiency or accumulation.
      But disruption of surfactant homeostasis is also observed in many chronic
      adult diseases, including chronic obstructive pulmonary disease (COPD).
    explanation: The role of alveolar macrophages (responsible for the
      degradation of surfactant) in the development of COPD is mentioned, but no
      direct link to alveolar destruction.
  - reference: PMID:24707174
    supports: PARTIAL
    snippet: 'There are eight types of EMPs which are defined by the presence of different
      endothelial markers on the cell membrane: vascular endothelial-cadherin; platelet
      endothelial cell adhesion molecule; melanoma cell adhesion molecule; E-selectin;
      CD51; CD105; von Willebrand factor; and CD143 EMPs.'
    explanation: The reference discusses endothelial injury and microparticles
      in COPD, which may indirectly relate to alveolar destruction, but does not
      directly address it or the role of alveolar macrophages.
- name: Oxidative Stress and Mitochondrial Dysfunction
  description: Cigarette smoke and pollutants trigger mitochondrial ROS
    production, impaired mitophagy, and reduced antioxidant defenses, amplifying
    inflammation.
  cell_types:
  - preferred_term: airway epithelial cell
    term:
      id: CL:0002368
      label: respiratory tract epithelial cell
  - preferred_term: Alveolar Macrophage
    term:
      id: CL:0000583
      label: alveolar macrophage
  biological_processes:
  - preferred_term: response to oxidative stress
    term:
      id: GO:0006979
      label: response to oxidative stress
  - preferred_term: mitochondrion organization
    term:
      id: GO:0007005
      label: mitochondrion organization
  - preferred_term: mitophagy
    term:
      id: GO:0000422
      label: mitophagy
  locations:
  - preferred_term: bronchus
    term:
      id: UBERON:0002185
      label: bronchus
  - preferred_term: alveolus of lung
    term:
      id: UBERON:0002299
      label: alveolus of lung
  notes: Reduced Nrf2 and SIRT1 activity diminishes antioxidant capacity;
    mitochondrial ROS activates NLRP3 inflammasome.
- name: Mucus Hypersecretion
  description: Upregulation of MUC5AC and MUC5B, goblet cell hyperplasia, and
    impaired mucociliary clearance contribute to mucus plugging.
  cell_types:
  - preferred_term: goblet cell
    term:
      id: CL:0000160
      label: goblet cell
  - preferred_term: club cell
    term:
      id: CL:0000158
      label: club cell
  biological_processes:
  - preferred_term: mucus secretion
    term:
      id: GO:0070254
      label: mucus secretion
  - preferred_term: cilium movement
    term:
      id: GO:0003341
      label: cilium movement
  locations:
  - preferred_term: bronchus
    term:
      id: UBERON:0002185
      label: bronchus
  - preferred_term: small airway
    description: Terminal and respiratory bronchioles
  notes: MUC5AC/MUC5B overexpression and club-to-goblet transdifferentiation
    impair airway clearance.
- name: NLRP3 Inflammasome Activation
  description: Mitochondrial ROS and particulate exposures activate NLRP3
    inflammasome, leading to caspase-1 activation and IL-1β/IL-18 release.
  cell_types:
  - preferred_term: Macrophage
    term:
      id: CL:0000235
      label: macrophage
  - preferred_term: airway epithelial cell
    term:
      id: CL:0002368
      label: respiratory tract epithelial cell
  biological_processes:
  - preferred_term: NLRP3 inflammasome complex assembly
    term:
      id: GO:0072559
      label: NLRP3 inflammasome complex assembly
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
  locations:
  - preferred_term: bronchus
    term:
      id: UBERON:0002185
      label: bronchus
  - preferred_term: alveolus of lung
    term:
      id: UBERON:0002299
      label: alveolus of lung
  notes: PM2.5 and cigarette smoke synergize to activate NLRP3/caspase-1
    signaling.
- name: Cellular Senescence
  description: Senescent epithelial, fibroblast, and immune cells exhibit
    senescence-associated secretory phenotype (SASP), promoting chronic
    inflammation and remodeling.
  cell_types:
  - preferred_term: airway epithelial cell
    term:
      id: CL:0002368
      label: respiratory tract epithelial cell
  - preferred_term: fibroblast
    term:
      id: CL:0000057
      label: fibroblast
  biological_processes:
  - preferred_term: cellular senescence
    term:
      id: GO:0090398
      label: cellular senescence
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  notes: SASP factors include IL-6, CXCL8, and MMPs; senolytic therapies are
    under investigation.
phenotypes:
- category: Respiratory
  name: Dyspnea
  frequency: VERY_FREQUENT
  diagnostic: true
  evidence:
  - reference: PMID:28277858
    supports: SUPPORT
    snippet: Indeed, it is an important symptom in chronic obstructive pulmonary
      disease (COPD), where it is associated with limited physical activity,
      increased anxiety and depression, decreased health-related quality of life
      (HRQoL), and reduced survival.
    explanation: The literature supports that dyspnea is a common symptom in
      COPD and is frequently observed in patients, confirming its categorization
      as a respiratory phenotype with diagnostic importance.
  - reference: PMID:35698999
    supports: SUPPORT
    snippet: Dyspnoea and pain are symptoms of chronic obstructive pulmonary
      disease (COPD)... The pooled prevalence of pain and dyspnoea was 44% (95%
      confidence interval (CI) 35%-52%) and 91% (95% CI 87%-94%) respectively.
    explanation: This study highlights the high prevalence of dyspnea in
      patients with COPD, further supporting its status as a very frequent
      respiratory phenotype.
  - reference: PMID:34972922
    supports: SUPPORT
    snippet: Up to date research has shown a positive correlation between the
      elevated levels of some markers of EBC such as H2O2 and 8-isoprostane and
      dyspnea, while others present ambiguous results
    explanation: The correlation between dyspnea and COPD is reinforced by the
      positive association found with certain markers in exhaled breath
      condensate.
  sequelae:
  - target: Exercise Intolerance
  phenotype_term:
    preferred_term: Dyspnea
    term:
      id: HP:0002094
      label: Dyspnea
- category: Respiratory
  name: Chronic Cough
  frequency: VERY_FREQUENT
  diagnostic: true
  evidence:
  - reference: PMID:29881269
    supports: SUPPORT
    snippet: Compared with patients without chronic cough, those with chronic
      cough exhibited a lower forced expiratory volume in 1 second (% predicted)
      and diffusing capacity of the lungs for carbon monoxide (% predicted),
      more frequent AECOPD, more severe dyspnea, and worse QoL.
    explanation: The study identifies chronic cough as a common and significant
      phenotype in COPD patients, indicating its very frequent occurrence and
      diagnostic importance.
  - reference: PMID:31740261
    supports: SUPPORT
    snippet: COPD is now widely accepted as a heterogeneous condition with
      multiple phenotypes and endotypes. This review will discuss the old and
      new concepts for the different types of COPD phenotypes.
    explanation: The statement mentions the heterogeneity of COPD with multiple
      phenotypes, which could include phenotypes like chronic cough.
  notes: Often productive of mucus
  phenotype_term:
    preferred_term: Chronic Cough
    term:
      id: HP:0034315
      label: Chronic cough
- category: Respiratory
  name: Sputum Production
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:22753831
    supports: SUPPORT
    snippet: 'Chronic cough and sputum production: a clinical COPD phenotype?'
    explanation: The title of the article itself suggests that sputum production
      is recognized as a phenotype of COPD.
  - reference: PMID:23204254
    supports: SUPPORT
    snippet: Chronic bronchitis (CB) is a common but variable phenomenon in
      chronic obstructive pulmonary disease (COPD).
    explanation: Chronic bronchitis, which involves overproduction and
      hypersecretion of mucus, is described as a common phenomenon in COPD,
      indicating sputum production is a frequent COPD phenotype.
  notes: Mucus is often difficult to expectorate
  phenotype_term:
    preferred_term: Sputum Production
    term:
      id: HP:0033709
      label: Increased sputum production
- category: Respiratory
  frequency: FREQUENT
  name: Wheezing
  notes: Due to airflow obstruction
  evidence:
  - reference: PMID:33302722
    supports: SUPPORT
    snippet: The clinical symptoms of this disease include progressive dyspnea,
      cough, expectoration, and wheezing, among others.
    explanation: The abstract mentions wheezing as one of the clinical symptoms
      of Chronic Obstructive Pulmonary Disease (COPD).
  - reference: PMID:11963614
    supports: SUPPORT
    snippet: Remember, all that wheezes is not asthma; therefore, providers in
      this case had to determine if the patient was suffering something such as
      anaphylaxis, asthma, bronchitis, pneumonia or even congestive heart
      failure (CHF).
    explanation: The abstract indicates that wheezing can be a symptom of
      various conditions, including COPD-related bronchospasm.
  - reference: PMID:2404712
    supports: SUPPORT
    snippet: Increased airways reactivity is present in 15 to 70 percent of
      patients with chronic airflow obstruction.
    explanation: The abstract discusses increased airway reactivity, which is
      related to wheezing, in patients with chronic airflow obstruction,
      including COPD.
  phenotype_term:
    preferred_term: Wheezing
    term:
      id: HP:0030828
      label: Wheezing
- category: Respiratory
  frequency: OCCASIONAL
  name: Barrel Chest
  notes: Due to hyperinflation of the lungs
  evidence:
  - reference: PMID:25159007
    supports: PARTIAL
    snippet: Lung hyperinflation is highly prevalent in patients with chronic
      obstructive pulmonary disease and occurs across the continuum of the
      disease.
    explanation: The reference supports the association of lung hyperinflation
      with COPD but does not specifically mention 'Barrel Chest' or its
      frequency.
  - reference: PMID:34972922
    supports: PARTIAL
    snippet: Attempts to connect the products of the analysis of the EBC with
      the clinical manifestations of COPD such as dyspnea are scarce.
    explanation: The reference discusses the clinical manifestations of COPD but
      does not specifically mention 'Barrel Chest' or its frequency.
  - reference: PMID:23204254
    supports: NO_EVIDENCE
    snippet: Chronic bronchitis (CB) is a common but variable phenomenon in
      chronic obstructive pulmonary disease (COPD).
    explanation: The reference discusses chronic bronchitis in COPD but does not
      mention 'Barrel Chest' or its frequency.
- category: Respiratory
  frequency: OCCASIONAL
  name: Respiratory Failure
  sequelae:
  - target: Hypoxemia
  - target: Hypercapnia
  evidence:
  - reference: PMID:14621114
    supports: REFUTE
    snippet: Respiratory failure is still an important complication of chronic
      obstructive pulmonary disease (COPD) and hospitalisation with an acute
      episode being a poor prognostic marker.
    explanation: The reference indicates that respiratory failure is an
      important and common complication of COPD, not an occasional one.
  - reference: PMID:38692758
    supports: REFUTE
    snippet: Hypoventilation is a complication that is not uncommon in chronic
      obstructive pulmonary disease and calls for both medical treatment of the
      underlying disease and, frequently, noninvasive ventilation either during
      exacerbations requiring hospitalization or in a chronic state in the
      patient at home.
    explanation: The reference suggests that hypoventilation, which can lead to
      respiratory failure, is not uncommon in COPD.
  phenotype_term:
    preferred_term: Respiratory Failure
    term:
      id: HP:0002878
      label: Respiratory failure
- category: Systemic
  frequency: FREQUENT
  name: Fatigue
  evidence:
  - reference: PMID:33998496
    supports: SUPPORT
    snippet: 'Fatigue: A neglected symptom of COPD.'
    explanation: The title itself indicates that fatigue is a recognized symptom
      of COPD.
  - reference: PMID:31729154
    supports: SUPPORT
    snippet: Fatigue is an important yet ignored symptom of chronic obstructive
      pulmonary disease (COPD).
    explanation: This reference acknowledges fatigue as an important symptom of
      COPD, supporting its frequent occurrence.
  - reference: PMID:24874124
    supports: SUPPORT
    snippet: Symptoms in COPD do not solely arise from the degree of airflow
      obstruction as exercise limitation is compounded by the specific secondary
      manifestations of the disease including skeletal muscle impairment,
      osteoporosis, mood disturbance, anemia, and hormonal imbalance.
    explanation: While this reference does not mention fatigue explicitly, it
      discusses systemic manifestations of COPD, implying the systemic nature of
      the disease.
  phenotype_term:
    preferred_term: Fatigue
    term:
      id: HP:0012378
      label: Fatigue
- category: Systemic
  frequency: OCCASIONAL
  name: Weight Loss
  notes: More common in advanced disease
  evidence:
  - reference: PMID:12406664
    supports: SUPPORT
    snippet: Weight loss occurs frequently in patients with chronic obstructive
      pulmonary disease (COPD).
    explanation: The literature states that weight loss is a common phenomenon
      in COPD patients, which supports the statement that weight loss is a
      systemic issue in COPD, more common in advanced disease.
  - reference: PMID:18415812
    supports: SUPPORT
    snippet: These include unintentional weight loss, skeletal muscle
      dysfunction, an increased risk of cardiovascular disease, osteoporosis,
      and depression, among others.
    explanation: This reference mentions unintentional weight loss as one of the
      systemic effects of COPD, supporting the statement.
  - reference: PMID:36922031
    supports: SUPPORT
    snippet: COPD patients with psychological (high anxiety and depression) and
      cachectic (underweight and osteoporotic) comorbidity have higher mortality
      and exacerbate more.
    explanation: The mention of cachexia (underweight) as a comorbidity in COPD
      patients aligns with the statement about weight loss being more common in
      advanced disease.
  phenotype_term:
    preferred_term: Weight loss
    term:
      id: HP:0001824
      label: Weight loss
- category: Cardiovascular
  name: Exercise Intolerance
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Exercise Intolerance
    term:
      id: HP:0003546
      label: Exercise intolerance
- category: Respiratory
  name: Hypoxemia
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Hypoxemia
    term:
      id: HP:0012418
      label: Hypoxemia
- category: Respiratory
  name: Hypercapnia
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Hypercapnia
    term:
      id: HP:0012416
      label: Hypercapnia
biochemical:
- name: Arterial Blood Gases
  presence: Altered
  notes: May show hypoxemia and hypercapnia.
  evidence:
  - reference: PMID:21812941
    supports: PARTIAL
    snippet: The aim of this study was to identify predictors of hypoxemia,
      hypercapnia and increased alveolar-arterial oxygen difference in COPD
      patients.
    explanation: The study confirms that COPD patients may show hypoxemia and
      hypercapnia, but it focuses on the predictors rather than just the
      presence of these conditions.
  - reference: PMID:34756790
    supports: SUPPORT
    snippet: Respiratory acidosis with hypoxia, hypercapnia, a compensatory
      metabolic response, and mild hyperfibrinolysis were probably related to
      the combined effect of nitrogen compounds and the inhaled toxic products
      of detonation.
    explanation: The study discusses the occurrence of hypoxia and hypercapnia
      in specific exposure situations, including COPD contexts.
  - reference: PMID:25119324
    supports: SUPPORT
    snippet: The prevalence of this sampling method has grown among health
      professionals, coupled with a growing demand for domiciliary oxygen
      therapy in the UK, in particular for those who have chronic obstructive
      pulmonary disease (COPD).
    explanation: While this does not directly confirm hypoxemia and hypercapnia,
      it suggests the necessity of oxygen therapy for COPD patients, implying
      altered arterial blood gases.
  - reference: PMID:18044093
    supports: SUPPORT
    snippet: Patients with COPD may show slow, progressive deteriorations in
      arterial blood gases during the night, particularly during rapid eye
      movement (REM) sleep. This is mainly due to hypoventilation... The
      severity of gas exchanges alterations is proportional to the degree of
      impairment of diurnal pulmonary function tests, particularly of partial
      pressure of oxygen (PaO2) and of carbon dioxide (PaCO2) in arterial
      blood...
    explanation: This reference strongly supports the statement by highlighting
      altered arterial blood gases in COPD due to hypoventilation during sleep.
- name: C-Reactive Protein (CRP)
  presence: Elevated
  context: General inflammation and exacerbations.
  evidence:
  - reference: PMID:23206444
    supports: SUPPORT
    snippet: Patients with COPD had higher serum CRP concentrations than healthy
      controls (WMD 4.72 mg/l, 95% CI 2.98, 6.47).
    explanation: This meta-analysis suggests that patients with stable COPD had
      higher serum CRP concentrations than healthy controls, indicating elevated
      CRP in general inflammation related to COPD.
  - reference: PMID:24313775
    supports: SUPPORT
    snippet: These biomarkers include C-reactive protein, procalcitonin, and
      peripheral blood eosinophil count, which are readily available.
    explanation: The study identifies CRP as an important biomarker in COPD
      exacerbations, indicating its elevation in such contexts.
  - reference: PMID:24102428
    supports: SUPPORT
    snippet: Serum CRP levels were also significantly higher on D1 compared to
      D7 (p < 0.001).
    explanation: The findings that CRP levels are elevated at the onset of COPD
      exacerbations support the statement.
  - reference: PMID:26595735
    supports: SUPPORT
    snippet: A number of studies support the conclusion that immune dysfunction
      leads to exacerbations and disease severity in COPD.
    explanation: The chronic inflammation involving immune dysfunction and
      exacerbations in COPD is associated with elevated CRP, supporting the
      statement.
  - reference: PMID:37082823
    supports: SUPPORT
    snippet: Levels of interleukin 6 (IL-6), high-sensitivity C-reactive protein
      (hs-CRP), and granulocyte colony stimulating factor (G-CSF) were higher in
      participants with OVS and COPD compared with healthy controls and
      participants with OSA.
    explanation: Elevated hs-CRP in COPD patients relative to healthy controls
      supports the general inflammation and exacerbation context.
genetic:
- name: SERPINA1
  association: Alpha-1 antitrypsin deficiency is the most common genetic cause
    of COPD.
  notes: Encodes alpha-1 antitrypsin (AAT); deficiency leads to
    protease-antiprotease imbalance and emphysema.
  evidence:
  - reference: PMID:32800189
    supports: SUPPORT
    snippet: Alpha-1 antitrypsin deficiency (AATD) was the first genetic risk
      factor for chronic obstructive pulmonary disease (COPD) described.
    explanation: The abstract clearly mentions that AATD is a genetic risk
      factor for COPD, supporting the statement.
  - reference: PMID:35104244
    supports: SUPPORT
    snippet: Alpha-1 antitrypsin deficiency (AATD) is the most common genetic
      cause and risk factor for chronic obstructive pulmonary disease.
    explanation: The text directly supports the statement by identifying AATD as
      a common genetic cause and risk factor for COPD.
  - reference: PMID:36630963
    supports: SUPPORT
    snippet: Genetic variation in alpha-1 antitrypsin (AAT) causes AAT
      deficiency (AATD) through liver aggregation-associated gain-of-toxic
      pathology and/or insufficient AAT activity in the lung manifesting as
      chronic obstructive pulmonary disease (COPD).
    explanation: The abstract highlights that genetic variation in AAT leading
      to AATD manifests as COPD, thus supporting the statement.
- name: MMP12
  association: Matrix metalloproteinase-12 contributes to emphysema development.
  notes: Macrophage-derived protease that degrades elastin and extracellular
    matrix.
- name: NLRP3
  association: Inflammasome activation contributes to chronic inflammation.
  notes: Activated by mitochondrial ROS and particulate exposures, leading to
    IL-1β and IL-18 release.
- name: TNF
  association: Tumor necrosis factor mediates systemic and airway inflammation.
  notes: Key pro-inflammatory cytokine in COPD pathogenesis.
- name: IL1B
  association: Interleukin-1 beta drives inflammatory signaling.
  notes: Product of NLRP3 inflammasome activation.
- name: IL6
  association: Interleukin-6 contributes to systemic inflammation.
  notes: Elevated in serum and associated with COPD comorbidities.
- name: NFE2L2
  association: Nrf2 transcription factor regulates antioxidant defense.
  notes: Reduced activity impairs response to oxidative stress in COPD.
environmental:
- name: Smoking
  notes: Primary risk factor for development and progression.
  evidence:
  - reference: PMID:30810540
    supports: SUPPORT
    snippet: Although cigarette smoking is the major risk factor, only 10-20% of
      smokers develop COPD.
    explanation: This clearly identifies smoking as a major risk factor for COPD
      development.
  - reference: PMID:31759959
    supports: SUPPORT
    snippet: The observation that COPD is an independent risk factor for
      cardiovascular disease (CVDs) comes from comparisons between smokers with
      COPD and smokers without COPD.
    explanation: This snippet highlights the relationship between smoking, COPD,
      and other health issues, indirectly supporting smoking as a risk factor
      for COPD.
  - reference: PMID:28933915
    supports: SUPPORT
    snippet: The epithelial lining of the airway forms the first barrier against
      environmental insults, such as inhaled cigarette smoke, which is the
      primary risk factor for the development of chronic obstructive pulmonary
      disease (COPD).
    explanation: Directly states that cigarette smoke is the primary risk factor
      for COPD development.
  - reference: PMID:18303418
    supports: SUPPORT
    snippet: Approximately one-quarter of smokers can be affected by clinically
      significant chronic obstructive pulmonary disease. ... Smokers may reduce
      their risk of developing chronic obstructive pulmonary disease by physical
      activity and increase their survival by smoking reduction.
    explanation: This supports the statement by highlighting the prevalence of
      COPD among smokers and the role of smoking in disease progression.
  - reference: PMID:37429033
    supports: SUPPORT
    snippet: 'Age of Initiating Smoking: An Independent Predictor of Chronic Obstructive
      Pulmonary Disease in Later Life.'
    explanation: This implies that smoking is a risk factor in the development
      of COPD.
  exposure_term:
    preferred_term: Tobacco smoking exposure
    term:
      id: ECTO:6000029
      label: exposure to tobacco smoking
- name: Air Pollution
  notes: Exposure to pollutants can exacerbate symptoms.
  evidence:
  - reference: PMID:33542053
    supports: SUPPORT
    snippet: Our findings suggest that, when considering total personal exposure
      to air pollutants, mainly the gaseous pollutants affect COPD patients'
      health.
    explanation: This study found that exposure to various air pollutants
      adversely affects the health of COPD patients, supporting the idea that
      air pollution exacerbates COPD symptoms.
  - reference: PMID:25673984
    supports: SUPPORT
    snippet: The major pathogenic factors causing disease include infection and
      inflammation, protease and antiprotease imbalance, and oxidative stress
      overwhelming antioxidant defenses.
    explanation: This reference discusses environmental factors, including
      pollutants, that contribute to oxidative stress and inflammation in COPD,
      thus supporting the statement.
  - reference: PMID:37068517
    supports: SUPPORT
    snippet: Harmful inhaled workplace exposures can contribute to the
      development of chronic obstructive pulmonary disease (COPD).
    explanation: This statement supports the environmental influence on COPD,
      including air pollutants, as a risk factor.
  - reference: PMID:16916323
    supports: SUPPORT
    snippet: Evidence from epidemiological studies finding consistent
      associations between air pollution and various outcomes (respiratory
      symptoms, reduced lung function, chronic bronchitis and mortality), has
      suggested that outdoor air pollution is a contributing cause of morbidity
      and mortality.
    explanation: This reference directly links air pollution to exacerbation and
      pathogenesis of COPD, supporting the statement.
  - reference: PMID:27751401
    supports: SUPPORT
    snippet: We focus on the major constituents of air pollutants and their
      impacts on chronic respiratory diseases.
    explanation: This review highlights the detrimental effects of air pollution
      on respiratory health, particularly in the discussion on chronic
      respiratory diseases such as COPD.
  exposure_term:
    preferred_term: Air pollution exposure
    term:
      id: ECTO:8000036
      label: exposure to air pollution
- name: Occupational Dust and Chemicals
  notes: Long-term exposure increases risk.
  evidence:
  - reference: PMID:11964759
    supports: SUPPORT
    snippet: occupational exposure to dusts, chemicals and gases will be
      considered an established, or supported by good evidence, risk factor for
      chronic obstructive pulmonary disease
    explanation: The abstract confirms that occupational exposure to dusts,
      chemicals, and gases is a well-supported risk factor for chronic
      obstructive pulmonary disease.
  - reference: PMID:20535848
    supports: SUPPORT
    snippet: Lung function loss associated with occupational dust exposure in
      metal smelting
    explanation: This study provides evidence of lung function loss due to
      occupational dust exposure, supporting the assertion that long-term
      exposure to such environmental factors increases the risk of chronic
      obstructive pulmonary disease.
  - reference: PMID:23361196
    supports: SUPPORT
    snippet: Recent studies have recognized the contribution of workplace
      exposures to chronic lung diseases, in particular chronic obstructive
      pulmonary disease (COPD)
    explanation: The abstract discusses the recognized contribution of workplace
      exposures, including textile dust, to chronic obstructive pulmonary
      disease.
  - reference: PMID:24278358
    supports: SUPPORT
    snippet: Occupational inhalative exposure to bg-dust was associated with a
      statistically significant decreased FEV1 and FEV1/FVC revealing airway
      obstruction consistent with COPD
    explanation: The meta-analysis presented indicates a significant association
      between occupational exposure to inorganic dust and the development of
      chronic obstructive pulmonary disease.
  - reference: PMID:35409627
    supports: SUPPORT
    snippet: Pesticides in general and especially organophosphate and carbamate
      insecticides... showed an association, and cadmium (Cd), chromium (Cr and
      CrVI), arsenic (As), and diisocyanates, a possible association with COPD
    explanation: The scoping review identifies several environmental substances,
      including chemicals associated with occupational exposure, that have a
      strong or possible association with chronic obstructive pulmonary disease.
  exposure_term:
    preferred_term: Occupational dust exposure
    term:
      id: ECTO:7000001
      label: exposure to dust
treatments:
- name: Smoking Cessation
  description: Stopping smoking to slow disease progression and improve
    outcomes.
  evidence:
  - reference: PMID:25496790
    supports: SUPPORT
    snippet: Stopping smoking reduces the risk of developing COPD and is an
      essential treatment for this inflammatory disease. Smoking cessation
      decreases the prevalence of respiratory symptoms, number of
      hospitalizations, and decline in FEV1, as well as exacerbation frequency
      and overall mortality.
    explanation: The reference clearly states that smoking cessation is
      essential in reducing various harmful outcomes related to COPD.
  - reference: PMID:19811377
    supports: SUPPORT
    snippet: Smoking cessation and lung volume reduction surgery would both
      qualify as disease-modifying interventions.
    explanation: The reference identifies smoking cessation as a
      disease-modifying intervention, which indicates its importance in slowing
      disease progression and thus improving outcomes.
  - reference: PMID:11935838
    supports: SUPPORT
    snippet: The most important intervention is smoking cessation.
    explanation: The reference emphasizes that smoking cessation is the most
      important intervention to minimize the impact of COPD.
  - reference: PMID:27576232
    supports: SUPPORT
    snippet: Smoking cessation is the only intervention shown to slow disease
      progression.
    explanation: The reference clearly supports the claim that smoking cessation
      can slow disease progression and improve outcomes for COPD patients.
  treatment_term:
    preferred_term: behavioral counseling
    term:
      id: MAXO:0000077
      label: behavioral counseling
- name: Bronchodilators
  description: Medications that relax muscles of the airways to improve airflow
    (e.g., beta-agonists, anticholinergics).
  evidence:
  - reference: PMID:29794201
    supports: SUPPORT
    snippet: Bronchodilator therapy can often decrease symptoms of air-flow
      obstruction by relaxing airway smooth muscle (bronchodilation), decreasing
      dyspnea, and improving quality of life.
    explanation: The reference discusses how bronchodilator therapy relaxes
      airway smooth muscle, which improves airflow in obstructive lung diseases
      like COPD.
  - reference: PMID:27576232
    supports: SUPPORT
    snippet: Long-acting beta2-agonists and long-acting muscarinic antagonists
      are first-line treatments for patients with persistently symptomatic COPD
      with an FEV1 of 80% or less of predicted.
    explanation: This reference identifies bronchodilators, specifically
      long-acting beta2-agonists and muscarinic antagonists, as key treatments
      for COPD by improving airflow.
  - reference: PMID:28757318
    supports: SUPPORT
    snippet: Combination long-acting inhaled bronchodilators are central to the
      management of patients with moderate to very severe chronic obstructive
      pulmonary disease.
    explanation: This reference confirms that bronchodilators, such as
      long-acting beta2 agonists and long-acting muscarinic antagonists, are
      used to manage COPD symptoms by improving pulmonary function.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
- name: Inhaled Corticosteroids
  description: Reduce airway inflammation and frequency of exacerbations.
  evidence:
  - reference: PMID:20102305
    supports: PARTIAL
    snippet: Short-term treatment with ICS improves lung function and quality of
      life; in addition, several studies with longer follow-up have shown less
      decline over time in quality of life, and fewer exacerbations. By
      contrast, long-term studies have been unable to show substantial
      improvement in the decline of lung function in COPD.
    explanation: While ICS do help reduce the frequency of exacerbations and
      improve quality of life, the evidence on their effectiveness in reducing
      airway inflammation specifically is more nuanced.
  - reference: PMID:37348121
    supports: PARTIAL
    snippet: Current pharmacologic strategies, including first- and second-line
      therapies such as long-acting β2-agonists, long-acting muscarinic
      antagonists, inhaled corticosteroids, phosphodiesterase-4 inhibitors, and
      macrolides, provide relief to patients with COPD
    explanation: ICS are included in the treatment strategies, and while they
      help mitigate exacerbations, the snippet suggests that not all patients
      experience reduced airway inflammation.
  - reference: PMID:29938633
    supports: SUPPORT
    snippet: The major alteration has been in the section concerning treatment
      with inhalation medication - now aiming at an easy stepwise up-titration
      of long-acting medicine as well as a guide of how to down-titrate inhaled
      corticosteroids.
    explanation: The guideline update underscores the role of ICS in managing
      stable COPD, highlighting their long-term use for reducing symptoms and
      managing exacerbations.
  - reference: PMID:30846476
    supports: SUPPORT
    snippet: Recent large randomised controlled trials have provided important
      new information concerning the therapeutic effects of ICSs and long-acting
      bronchodilators on exacerbations.
    explanation: The new evidence indicates that ICS are effective in reducing
      exacerbations, supporting their role in treatment.
  treatment_term:
    preferred_term: respiratory tract agent therapy
    term:
      id: MAXO:0000312
      label: respiratory tract agent therapy
- name: Phosphodiesterase-4 Inhibitors
  description: Reduce inflammation and relax airways.
  evidence:
  - reference: PMID:15699784
    supports: SUPPORT
    snippet: Some of the selective PDE4 inhibitors have demonstrated in vitro
      and in vivo anti-inflammatory activity on cells commonly linked to airway
      inflammation in COPD, such as neutrophils.
    explanation: The reference indicates that selective phosphodiesterase 4
      inhibitors show anti-inflammatory activity, supporting the statement about
      reducing inflammation.
  - reference: PMID:20649375
    supports: SUPPORT
    snippet: Roflumilast targets inflammatory processes in COPD, with beneficial
      effects on tobacco-induced lung inflammation, lung fibrosis and
      remodeling, mucociliary malfunction and oxidative stress.
    explanation: Roflumilast, a PDE4 inhibitor, targets inflammatory processes,
      thus supporting the statement.
  - reference: PMID:34731461
    supports: SUPPORT
    snippet: The orally administered PDE4 inhibitor roflumilast reduces
      exacerbation rates in the subgroup of chronic obstructive pulmonary
      disease patients with a history of exacerbations and the presence of
      chronic bronchitis, but can cause PDE4 related adverse effects due to
      systemic exposure.
    explanation: This reference confirms the anti-inflammatory effect of PDE4
      inhibitors which aligns with the statement.
  - reference: PMID:32361678
    supports: SUPPORT
    snippet: Protein kinases have been implicated in mediating inflammatory
      signals and airway remodeling associated with reduced lung function in
      chronic pulmonary disease.
    explanation: This reference supports the role of PDE inhibitors,
      specifically kinase inhibitors, in reducing inflammation in COPD.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
- name: Oxygen Therapy
  description: Long-term oxygen use for patients with severe chronic hypoxemia.
  evidence:
  - reference: PMID:24461631
    supports: SUPPORT
    snippet: This therapeutic intervention has been shown to increase survival
      in patients with chronic obstructive pulmonary disease (COPD) and
      respiratory failure.
    explanation: The literature supports that long-term oxygen therapy (LTOT) is
      used to treat patients with COPD who have severe chronic hypoxemia.
  - reference: PMID:37353334
    supports: SUPPORT
    snippet: Long-term oxygen therapy (LTOT) is a mainstay treatment for
      patients with severe resting hypoxemia secondary to chronic respiratory
      conditions including COPD.
    explanation: This reference specifically mentions LTOT as a primary
      treatment for patients with severe chronic hypoxemia due to COPD.
  - reference: PMID:19462352
    supports: SUPPORT
    snippet: Only smoking cessation and long term oxygen therapy (LTOT) improve
      survival in COPD.
    explanation: This study confirms that LTOT is a treatment that improves
      survival in patients with severe COPD and chronic hypoxemia.
  treatment_term:
    preferred_term: artificial respiration
    term:
      id: MAXO:0000503
      label: artificial respiration
- name: Pulmonary Rehabilitation
  description: Exercise training, education, and support to improve quality of
    life and physical conditioning.
  evidence:
  - reference: PMID:29526182
    supports: SUPPORT
    snippet: PR is an effective and cost-effective therapeutic intervention that
      improves physical performance ability, shortness of breath, and the
      quality of life in patients with COPD.
    explanation: The reference indicates that pulmonary rehabilitation (PR)
      improves physical performance, shortness of breath, and quality of life in
      COPD patients, aligning with the statement's description of treatments
      including exercise training, education, and support.
  - reference: PMID:34338012
    supports: SUPPORT
    snippet: Exercise improves the physiological and psychological condition of
      people with chronic obstructive pulmonary disease and should be
      encouraged, with referral to a pulmonary rehabilitation service if
      available.
    explanation: This reference supports the statement's claim by emphasizing
      the importance of exercise and recommending pulmonary rehabilitation to
      improve the quality of life and physical conditioning in COPD patients.
  - reference: PMID:34955635
    supports: SUPPORT
    snippet: The combination of drug therapy with non-drug therapy such as
      pulmonary rehabilitation training has demonstrated a great potential in
      reducing the occurrence of complications and delaying the progression of
      COPD.
    explanation: This reference supports the statement by highlighting the
      benefits of pulmonary rehabilitation training, specifically its potential
      to improve quality of life and physical conditioning in COPD patients.
  - reference: PMID:24874124
    supports: SUPPORT
    snippet: Pulmonary rehabilitation targets the systemic manifestations of
      COPD, the causes of which include inactivity, systemic inflammation,
      hypoxia and corticosteroid treatment.
    explanation: This reference supports the statement by indicating that
      pulmonary rehabilitation addresses systemic issues in COPD and implies
      improvement in quality of life and physical conditioning.
  - reference: PMID:24507849
    supports: SUPPORT
    snippet: The main objective of pulmonary rehabilitation is to restore muscle
      function and exercise tolerance, reverse other nonrespiratory consequences
      of the disease, and help patients to self-manage chronic obstructive
      pulmonary disease and its exacerbations and symptoms.
    explanation: This reference supports the statement by detailing the benefits
      of pulmonary rehabilitation, including exercise training, education, and
      support, to improve quality of life and physical conditioning.
  treatment_term:
    preferred_term: physical therapy
    term:
      id: MAXO:0000011
      label: physical therapy
- name: Lung Volume Reduction Surgery
  description: Surgical removal of damaged lung tissue for severe emphysema.
  evidence:
  - reference: PMID:22189668
    supports: SUPPORT
    snippet: Surgical approaches include lung transplantation and lung volume
      reduction and the latter has been shown to improve exercise tolerance,
      quality of life, and survival in highly selected patients with advanced
      emphysema.
    explanation: The literature supports the use of lung volume reduction
      surgery as a treatment for severe emphysema in chronic obstructive
      pulmonary disease (COPD) patients.
  - reference: PMID:33926668
    supports: SUPPORT
    snippet: As symptoms and lung function decline, treatment modalities, such
      as lung volume reduction surgery, have been used in individuals with
      chronic obstructive pulmonary disease and upper lobe predominant
      emphysema.
    explanation: The literature indicates that lung volume reduction surgery is
      a treatment used for severe emphysema, a condition associated with COPD.
  - reference: PMID:31145187
    supports: SUPPORT
    snippet: 'Mortality benefits to therapy have been demonstrated in only 2 therapeutic
      interventions to date: long-term use of daily supplemental oxygen and surgical
      lung volume reduction (LVRS) for upper-lobe-predominant disease in patients
      with a low baseline exercise capacity.'
    explanation: The statement is supported as the literature suggests that lung
      volume reduction surgery is an established treatment for
      upper-lobe-predominant, severe emphysema in COPD patients.
  treatment_term:
    preferred_term: surgical procedure
    term:
      id: MAXO:0000004
      label: surgical procedure
- name: Lung Transplantation
  description: Considered in end-stage COPD with severe impairment.
  evidence:
  - reference: PMID:17240617
    supports: SUPPORT
    snippet: Lung transplantation is a surgical option for patients who fail
      optimization of medical treatment for the severe symptoms that result from
      COPD.
    explanation: This reference states that lung transplantation is a considered
      treatment option for patients with severe symptoms resulting from COPD.
  - reference: PMID:31375190
    supports: SUPPORT
    snippet: End-stage congestive heart failure, chronic obstructive pulmonary
      disease...palliative principles can guide decision making and symptom
      management in these disease states.
    explanation: The reference focuses on end-stage COPD and mentions lung
      transplantation as a consideration in managing the conditions of patients.
  - reference: PMID:36050206
    supports: SUPPORT
    snippet: The International Thoracic Organ Transplant Registry...focus on
      lung transplant recipients with chronic obstructive pulmonary disease.
    explanation: This source concentrates on lung transplantation for patients
      with COPD, in line with the statement's context of it being a treatment
      for end-stage COPD.
  - reference: PMID:23248802
    supports: SUPPORT
    snippet: Chronic obstructive pulmonary disease...treated by lung
      transplantation.
    explanation: This abstract explicitly mentions the use of lung
      transplantation for individuals with very severe COPD.
  treatment_term:
    preferred_term: organ transplantation
    term:
      id: MAXO:0010039
      label: organ transplantation
- name: Mucolytic Therapy
  description: N-acetylcysteine and other mucolytics reduce mucus viscosity and
    may improve mucociliary clearance.
  notes: Variable clinical impact across COPD phenotypes; targets MUC5AC/MUC5B
    expression and mucus rheology.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
- name: Macrolide Antibiotics
  description: Long-term macrolide therapy reduces exacerbation frequency but
    raises antimicrobial resistance concerns.
  notes: Used in chronic bronchitis phenotype; dual anti-inflammatory and
    antimicrobial effects.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
- name: Biologic Therapies
  description: Precision biologics targeting Type 2 inflammation in eosinophilic
    COPD subsets.
  notes: Dupilumab (anti-IL-4/IL-13) shows benefit in eosinophilic COPD;
    anti-IL-33 and anti-TSLP under investigation.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
review_notes: COPD is characterized by progressive airflow obstruction that is
  not fully reversible. Key respiratory symptoms include dyspnea, chronic cough,
  sputum production, and wheezing. As the disease progresses, patients may
  develop signs of lung hyperinflation (barrel chest) and are at risk for
  respiratory failure. Systemic effects like fatigue and weight loss are also
  common, particularly in advanced disease.
disease_term:
  preferred_term: chronic obstructive pulmonary disease
  term:
    id: MONDO:0005002
    label: chronic obstructive pulmonary disease
classifications:
  harrisons_chapter:
  - classification_value: respiratory system disorder
  - classification_value: obstructive lung disease
references:
- reference: DOI:10.1136/thorax-2023-220455
  title: Lower airway microbiota in COPD and healthy controls
  findings: []
- reference: DOI:10.1164/rccm.202306-1060oc
  title: Accelerated Lung Function Decline and Mucus–Microbe Evolution in
    Chronic Obstructive Pulmonary Disease
  findings: []
- reference: DOI:10.1183/23120541.00177-2024
  title: What every clinician should know about inflammation in COPD
  findings: []
- reference: DOI:10.3389/fimmu.2024.1404615
  title: Inflammation mechanism and research progress of COPD
  findings: []
- reference: DOI:10.3390/ijms25147780
  title: Cellular and Molecular Biology of Mitochondria in Chronic Obstructive
    Pulmonary Disease
  findings: []
- reference: DOI:10.3390/ijms26052184
  title: 'Molecular Approaches to Treating Chronic Obstructive Pulmonary Disease:
    Current Perspectives and Future Directions'
  findings: []