- •
Asthma in childhood and chronic obstructive pulmonary disease (COPD) in smokers are easily distinguishable disease entities.
- •
There exist overlap phenotypes of asthma and COPD, such as asthma with neutrophilia and/or without bronchodilator response, and COPD with eosinophilia and/or some bronchodilator response.
- •
Differences in physiology, symptoms, inflammation, and remodeling between asthma and COPD are obscured by smoking. Hence asthma in a smoker and COPD appear similar (ie, they show
Asthma and Chronic Obstructive Pulmonary Disease: Similarities and Differences
Section snippets
Key points
Definitions
Asthma is currently defined as a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. The chronic inflammation is associated with airway hyperresponsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning. These episodes are usually associated with widespread, but variable, airflow obstruction within the lung that is often reversible either spontaneously or
Symptoms
It is difficult to differentiate asthma and COPD based on respiratory symptoms.16 In the extremes with a sudden attack of wheeze and dyspnea after allergen exposure, it is clear that this is compatible with asthma. However, in the chronic forms, symptoms are many times more diffuse and patients with asthma may have symptoms of chronic cough and/or sputum production17, 18 formerly thought to imply COPD, especially when irreversible airway obstruction has developed.19 In contrast, patients with
Genetics and environment
Genetic factors contribute to the development of both asthma and COPD, in conjunction with environmental factors. Many environmental factors contribute to both asthma and COPD and some only to either asthma or COPD alone. Table 2 shows an overview of these factors as published in a recent review.65 More severe airway hyperresponsiveness, lower lung function, maternal smoking during pregnancy, air pollution, and personal cigarette smoking are risk factors for development of both asthma and COPD.
Inflammation and remodeling
Inflammation and remodeling are present in COPD throughout the bronchial tree and lung tissue. There are 3 distinct processes present, and in different combinations in COPD: (1) chronic sputum production and cough, so called chronic bronchitis; (2) small airway disease; and (3) emphysema, which is the loss of elastic tissue in the peripheral lung.70 Respiratory bronchioles of young smokers are already inflamed,70 likely reflecting early signs of COPD. This inflammation has been shown to
Pharmacologic responses
One of the difficulties in discussing treatment response in asthma and COPD is that patients with overlap phenotypes of asthma and COPD have been systematically excluded from drug trials, which are designed to include patients with pure COPD and pure asthma. This exclusion represents a problem for evidence-based guidelines on obstructive airway disease. Travers and colleagues89 showed that only 5 of 100 individuals identified with COPD in a general population survey would fulfill inclusion
Summary
It is easy to differentiate pure asthma from pure COPD, because they reflect the extremes of a spectrum. However, in many, especially older, patients, features of both asthma and COPD can be present, leading to an overlap phenotype. There is no extensive literature available on the overlap phenotype, and interpretation of studies thus far has been hampered by differential age and smoking status in asthma and COPD. The balance of evidence so far suggests that the severity of airway obstruction
References (98)
- et al.
Bronchodilator reversibility in COPD
Chest
(2011) - et al.
Rationale for the Dutch hypothesis. Allergy and airway hyperresponsiveness as genetic factors and their interaction with environment in the development of asthma and COPD
Chest
(2004) - et al.
Fixed airflow obstruction due to asthma or chronic obstructive pulmonary disease: 5-year follow-up
J Allergy Clin Immunol
(2010) - et al.
The proportional Venn diagram of obstructive lung disease: two approximations from the United States and the United Kingdom
Chest
(2003) - et al.
Airway eosinophilia in remission and progression of asthma: accumulation with a fast decline of FEV(1)
Respir Med
(2010) - et al.
International Primary Care Respiratory Group (IPCRG) Guidelines: diagnosis of respiratory diseases in primary care
Prim Care Respir J
(2006) Airway mucus hypersecretion in asthma: an undervalued pathology?
Curr Opin Pharmacol
(2004)- et al.
Lung function and symptom improvement with fluticasone propionate/salmeterol and ipratropium bromide/albuterol in COPD: response by beta-agonist reversibility
Pulm Pharmacol Ther
(2008) - et al.
Small airway disease in asthma and COPD: clinical implications
Chest
(2011) - et al.
Small-airways dysfunction associates with respiratory symptoms and clinical features of asthma: a systematic review
J Allergy Clin Immunol
(2013)
Corticosteroids in chronic bronchitis and pulmonary emphysema
Chest
Airway smooth muscle in asthma: just a target for bronchodilation?
Clin Chest Med
Predictors of airway hyperresponsiveness differ between old and young patients with asthma
Chest
Burden of concomitant asthma and COPD in a Medicaid population
Chest
Consensus document on the overlap phenotype COPD-asthma in COPD
Arch Bronconeumol
Characteristics of adults dying with COPD
Chest
Genome-wide association study of lung function decline in adults with and without asthma
J Allergy Clin Immunol
Association between neutrophilic airway inflammation and airflow limitation in adults with asthma
Chest
External validity of randomized controlled trials in COPD
Respir Med
Improvements with tiotropium in COPD patients with concomitant asthma
Respir Med
The overlap syndrome of asthma and COPD: what are its features and how important is it?
Thorax
Pathologic similarities and differences between asthma and chronic obstructive pulmonary disease
Curr Opin Pulm Med
Effect of aging alone on mechanical properties of the normal adult human lung
J Appl Physiol
Airway epithelial changes in smokers but not in ex-smokers with asthma
Am J Respir Crit Care Med
Efficacy of low and high dose inhaled corticosteroid in smokers versus non-smokers with mild asthma
Thorax
I have taken my umbrella, so of course it does not rain
Thorax
The clinical features of the overlap between COPD and asthma
Respir Res
Epidemiology and management of common pulmonary diseases in older persons
J Gerontol A Biol Sci Med Sci
Identifying asthma and chronic obstructive pulmonary disease in patients with persistent cough presenting to general practitioners: descriptive study
BMJ
Risk factors associated with the presence of irreversible airflow limitation and reduced transfer coefficient in patients with asthma after 26 years of follow up
Thorax
Predictors of COPD symptoms: does the sex of the patient matter?
Eur Respir J
Chronic mucus hypersecretion in COPD and death from pulmonary infection
Eur Respir J
Atopy is a risk factor for respiratory symptoms in COPD patients: results from the EUROSCOP study
Respir Res
Bronchodilator responsiveness in patients with COPD
Eur Respir J
A 4-year trial of tiotropium in chronic obstructive pulmonary disease
N Engl J Med
Bronchodilator responsiveness as a phenotypic characteristic of established chronic obstructive pulmonary disease
Thorax
Partial reversibility of airflow limitation and increased exhaled NO and sputum eosinophilia in chronic obstructive pulmonary disease
Am J Respir Crit Care Med
CT-quantified emphysema in male heavy smokers: association with lung function decline
Thorax
Treatment of the bronchial tree from beginning to end: targeting small airway inflammation in asthma
Allergy
Infants with flow limitation at 4 weeks: outcome at 6 and 11 years
Am J Respir Crit Care Med
Comparison of inspiratory and expiratory resistance and reactance in patients with asthma and chronic obstructive pulmonary disease
Thorax
Nonreversible conductive airway ventilation heterogeneity in mild asthma
J Appl Physiol
Evidence of acinar airway involvement in asthma
Am J Respir Crit Care Med
Conductive and acinar lung-zone contributions to ventilation inhomogeneity in COPD
Am J Respir Crit Care Med
Computed tomography-based biomarker provides unique signature for diagnosis of COPD phenotypes and disease progression
Nat Med
Overview of 'allergy and allergic diseases: with a view to the future
Br Med Bull
The ENFUMOSA cross-sectional European multicentre study of the clinical phenotype of chronic severe asthma. European Network for Understanding Mechanisms of Severe Asthma
Eur Respir J
Cited by (80)
Evaluation and Management of Asthma and Chronic Obstructive Pulmonary Disease Exacerbation in the Emergency Department
2022, Emergency Medicine Clinics of North AmericaCitation Excerpt :Asthma and COPD are chronic diseases classically defined by airflow obstruction reversibility, but they differ regarding the specific component of the pulmonary system involved, prognosis, and local inflammation. It can also be difficult to differentiate them clinically in adults, and both conditions are associated with significant morbidity and mortality if not appropriately managed.11,13–18 Thus, emergency clinicians must understand the acute evaluation and management of the patient with obstructive lung disease exacerbation.
Utilizing Culturally Tailored Approaches and Participant Feedback to Successfully Implement an Exercise Intervention in Black Women with Asthma: Are There Lessons That Can Be Applied to Address Disparities in Asthma Outcomes?
2021, Journal of Allergy and Clinical Immunology: In PracticeThe value of bronchodilator response in FEV1 and FeNO for differentiating between chronic respiratory diseases: an observational study
2024, European Journal of Medical ResearchArtificial intelligence to differentiate asthma from COPD in medico-administrative databases
2022, BMC Pulmonary MedicineChemokine CXCL12 drives pericyte accumulation and airway remodeling in allergic airway disease
2022, Respiratory Research