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• COPD and asthma
• Prevalence
• Risk factors
• Diagnosis
• Management of COPD
• References

Summary of practice points	Level of evidence
Always attempt to make a firm diagnosis in patients with airflow limitation, because the natural history and optimal management of COPD and asthma differ significantly.	[√]
Consider COPD in all at-risk patients because early diagnosis and treatment improves outcomes.	II
Consider COPD in patients who have other smoking-related diseases.	I
Consider COPD in all smokers and ex-smokers older than 35 years.	II
Set up a system to alert you to consider COPD in at-risk patients: smokers, elderly patients, patients with a diagnosis of asthma who do not respond to treatment as expected.	[√]
Investigate breathlessness in patients at risk for COPD, even when the patient attributes it to ageing or poor fitness.	[√]
Investigate further whenever a patient mentions consistent sputum production or persistent cough.	[√]
The diagnosis of COPD is based on the demonstration of airflow limitation that is not fully reversible.	I
Anticholinergic bronchodilators and SABAs are effective in managing symptoms	I
Tiotropium and LABAs provide sustained relief of symptoms, improve exercise performance and reduce the frequency of severe exacerbations in moderate-to-severe COPD.	I
Short-course oral corticosteroids reduce the severity and duration of exacerbations.	[√]
Long-term use of oral corticosteroids is not recommended.	I
Pulmonary rehabilitation reduces dyspnoea, anxiety and depression, improves exercise capacity and quality of life and may reduce hospitalisation rates in patients with COPD.	I
Inhaled corticosteroids should be reserved for those with severe COPD and frequent exacerbations.	[√]
Assessment of walking distance and the patient's report of symptomatic improvement are appropriate guides to effectiveness of therapy.	[√]

Chronic obstructive pulmonary disease (COPD) is a progressive, disabling disease characterised by symptoms of breathlessness during physical activity and/or daily cough with or without sputum, airway inflammation and airflow limitation that is not fully reversible.

• The precursor conditions that most commonly lead to COPD are small-airway narrowing (with or without chronic bronchitis) and emphysema caused by smoking.¹
• Chronic bronchitis, emphysema and asthma overlap within COPD (Figure 1).
• COPD is characterised by intermittent acute exacerbations of symptoms (sputum production, breathing difficulties or both), which are usually due to respiratory tract infection, and can be significantly disabling.

Consider the possible diagnosis of COPD in all those who are at risk (e.g. smokers and ex-smokers, elderly patients) or who show airflow limitation that is not fully reversible.

An understanding of COPD is relevant to asthma management because:

• asthma and COPD have different prognoses and require different management^1,2
• both asthma and COPD can overlap or coexist
• asthma and COPD have many common features, and may be difficult to distinguish³
• both asthma and COPD are under-diagnosed in the elderly.^4,5

For more information on the diagnosis and management of COPD, see:

The COPD-X Plan: Australian and New Zealand guidelines for the management of chronic obstructive pulmonary disease 2006

Figure 1. Overlap of bronchitis, emphysema and asthma within COPD (represented by the shaded area).

Adapted from ALF and TSANZ COPDX plan 2006¹ with permission

Patients with well-controlled asthma usually have no airflow limitation. Symptoms may sometimes be experienced in the absence of   airflow limitation in patients with chronic bronchitis or, infrequently, those with emphysema.

COPD and asthma

In the past, asthma and COPD were thought to represent clearly distinguishable diseases: asthma was seen as a treatment-responsive and reversible inflammatory process, while COPD has been characterised by fixed and progressive airway narrowing and alveolar destruction not responsive to treatment. Current definitions emphasise these features as the classical form of each disease, but acknowledge that there can be significant overlap between asthma and COPD.^{1,3, 6-8}

• In COPD, some factors contributing to airflow limitation might be amenable to drug treatment - while in asthma, a degree of irreversible airflow limitation can occur in response to poorly controlled inflammation.⁹
• In some patients, airway disease meets diagnostic criteria for both asthma and COPD.
• Some experts consider that asthma and COPD represent different outcomes of a similar pathological process.
• An individual patient's clinical features might be determined by multiple factors including genetic predisposition, the specific type of damage, environmental factors and age.

In practice, it is useful to distinguish between the diagnoses of asthma and COPD in each individual patient's case, because there are important differences between the optimal management for each of these conditions.

Prevalence

Chronic obstructive pulmonary disease occurs almost exclusively in adults, and prevalence increases with age.¹⁰

• Approximately 50% of all smokers develop some airflow limitation, and 15%-20% will develop clinically significant disability.¹
• Approximately 9%-12% of people over 45 years old have symptomatic COPD^11,12
• The number of people with unacknowledged symptoms of chronic, poorly reversible airflow limitation has been estimated to be at least two to three times higher than the number of those with diagnosed COPD.^13,14

Risk factors

Tobacco smoking is the most important risk factor for COPD.

Other risk factors include:

• exposure to environmental tobacco smoke
• exposure to dusts and chemicals in the workplace
• exposure to indoor biomass fuel smoke in people from some traditional cultures
• a strong family history of COPD
• recurrent respiratory infections in childhood
• atopy
• alpha-1-antitrypsin deficiency (uncommon).

The possibility of COPD should be considered in:

• all patients with any other smoking-related disease
• all smokers and ex-smokers over 35 years old.

Diagnosis

Practice points

Always attempt to make a firm diagnosis in patients with airflow limitation, because the natural history and optimal management of COPD and asthma differ significantly. [√] Consider COPD in all at-risk patients because early diagnosis and treatment improves outcomes. (II) Consider COPD in patients who have other smoking-related diseases. (I) Consider COPD in all smokers and ex-smokers older than 35 years. (II) Set up a system to alert you to consider COPD in at-risk patients: smokers, elderly patients, patients with a diagnosis of asthma who do not respond to treatment as expected. [√] Investigate breathlessness in patients at risk for COPD, even when the patient attributes it to ageing or poor fitness. [√] Investigate further whenever a patient mentions consistent sputum production or persistent cough. [√] The diagnosis of COPD is based on the demonstration of airflow limitation that is not fully reversible. [√]

Practice tip Consider the possibility that a patient may have both COPD and asthma.

The differential diagnosis of COPD includes:

• other respiratory diseases (e.g. bronchiectasis, interstitial lung diseases)
• non-respiratory diseases (e.g. chronic heart failure, anaemia).

The diagnosis of COPD is based on the history, together with the demonstration of airflow limitation that is not fully reversible by performing spirometry before and after administration of a short-acting beta₂ agonist (SABA) bronchodilator.^15,16

Clinical features of asthma that distinguish it from COPD are:¹⁷

• significant variation in airflow limitation between visits
• significant variation in airflow limitation with different treatments
• reversal of airflow limitation on spirometry in response to a short-acting bronchodilator.

However, asthma and COPD can be difficult to distinguish - especially in older adults, in whom respiratory symptom patterns are frequently non-specific. Misdiagnosis is common.^15,18,19

Table 1. Symptoms of COPD

Major symptoms Breathlessness Cough Sputum production Other symptoms Common Chest tightness Wheezing Airway hyperresponsiveness In advanced disease Fatigue Poor appetite Weight loss

History

The history should include:

• symptoms (Table 1)
• exposure to risk factors, including occupational history ⁴
• factors that may suggest new-onset asthma in an older person, including post-retirement exposure to new allergens and sensitisers, use of medications that may precipitate bronchoconstriction (e.g. nonsteroidal anti-inflammatory drugs, beta-adrenergic receptor antagonists). See Asthma in the Elderly.

Physical examination

Physical examination is not a sensitive test for detecting mild-to-moderate COPD.^1,20

• Wheezing is not an indicator of severity and is often absent in stable, severe COPD
• The presence and severity of airflow limitation are impossible to determine by clinical signs.
• Chest overinflation (enlarged chest diameter, percussion hyper-resonance with loss of cardiac dullness, and reduced overall respiratory excursions) increases with worsening airflow limitation and emphysema.

Spirometry

Spirometry is the recommended method for confirming the diagnosis, assessing severity and monitoring COPD.¹

• The ratio of forced expiratory volume in one second (FEV₁) to vital capacity (VC) is a sensitive indicator of mild COPD.
• Peak expiratory flow (PEF) is not a sensitive measure of airway function in COPD.

Spirometry is indicated in patients with any of the following:

• unexplained breathlessness
• cough that is chronic (daily for two months) or intermittent and unusual
• frequent or unusual sputum production
• recurrent acute infective bronchitis
• risk factors (e.g. exposure to tobacco smoke, occupational dusts and chemicals, and a strong family history of COPD).

A degree of fixed airflow limitation is present if both the following are recorded 15-30 minutes after administration of SABA bronchodilator medication:

• The ratio of FEV₁ to forced vital capacity (FVC) is < 70% (< 0.70) and
• FEV₁ < 80% predicted.

For more information on the interpretation of spirometry in the diagnosis of COPD, see Spirometry. The Measurement and Interpretation of Ventilatory Function in Clinical Practice.

Other tests

Biomarkers from induced sputum or breath condensates are currently being evaluated for diagnostic use, but are not yet suitable for clinical use.^21-23

Special diagnostic considerations in elderly

• Elderly patients with COPD may not become aware of cough and dyspnoea or report any symptoms until they have already become significantly disabled and lung function is moderately impaired (e.g. FEV₁ may be reduced to as little as 50% of predicted value).¹⁵
• Asthma and COPD can be clinically indistinguishable in elderly patients.³

For a suggested approach to distinguishing asthma from COPD in older patients, see Asthma in the Elderly.

Practice tip Supplemental oxygen given during an acute asthma episode may cause respiratory depression and arrest in a patient with comorbid COPD. For more information on the management of acute asthma, including respiratory arrest, see Acute Asthma.

Management of COPD

Practice points

Anticholinergic bronchodilators and SABAs are effective in managing symptoms. (I) Tiotropium and LABAs provide sustained relief of symptoms, improve exercise performance and reduce the frequency of severe exacerbations in moderate-to-severe COPD. (I) Short-course oral corticosteroids reduce the severity and duration of exacerbations. (I) Long-term use of oral corticosteroids is not recommended. (I) Pulmonary rehabilitation reduces dyspnoea, anxiety and depression, improves exercise capacity and quality of life and may reduce hospitalisation rates in patients with COPD. (I) Inhaled corticosteroids should be reserved for those with severe COPD and frequent exacerbations. [√] Assessment of walking distance and the patient's report of symptomatic improvement are appropriate guides to effectiveness of therapy. [√]

The management of COPD must be tailored to the individual's symptoms and needs, aiming to maximise quality of life.^1,3 COPD is often complicated by comorbidities related to age and smoking history, such as ischaemic heart disease, chronic heart failure, diabetes mellitus, osteoporosis, sleep-disordered breathing, reduced ability to perform activities of daily living, physical deconditioning, depression, malnutrition, gastro-oesophageal reflux disease, lung cancer, and degenerative arthritis.

Current Australian and New Zealand ‘COPDX' guidelines are based on the following goals:¹

• C: confirm the diagnosis and assess severity
• O: optimise lung function
• P: prevent deterioration
• D: develop a support network and self-management plan
• X: manage exacerbations.

Smoking cessation is an important initial goal of COPD management, in order to reduce the rate of decline in lung function.²⁴

Pulmonary rehabilitation is an important part of management. It reduces dyspnoea and fatigue, improves patients' sense of control over their disease, and improves exercise capacity.²⁵ No changes in spirometry are usually seen, despite the significant improvements in function, quality of life and symptoms.

Practice point
Assessment of walking distance and the patient's report of symptomatic improvement are appropriate guides to effectiveness of therapy. [√]

Drug treatment

Optimal pharmacological management of COPD differs significantly from that of asthma (Table 2).

Drug treatment for patients with COPD is based on the following principles:¹

• Inhaled bronchodilators (short-acting beta₂ agonists and anticholinergic agents) are recommended for symptom relief. These agents:
  • are effective in the management of acute COPD exacerbations
  • may increase exercise capacity in the short term
  • are equally effective in COPD
  • may be better tolerated used in combination (compared with higher doses of either a SABA or anticholinergic agent used alone).

Although significant improvements in FEV₁ may not be seen in response to inhaled bronchodilators, patients may nevertheless experience symptomatic relief, increased exercise tolerance and improvement ability to perform activities of daily living. Spirometric measurements are generally poor predictors of clinical improvement in response to bronchodilators in COPD.²⁶

• Long-acting inhaled bronchodilators (salmeterol, eformoterol, tiotropium) provide sustained relief of symptoms, reduce the risk of exacerbations, and improve exercise capacity and health status in moderate-to-severe COPD. Current evidence suggests that tiotropium is more effective than either of the beta₂ agonists.²⁷
• Oral corticosteroids are used short-term to manage acute exacerbations. Short-course oral corticosteroids:
  • reduce the severity of acute COPD exacerbations and speed recovery ²⁸
  • are not recommended for long-term use.
• Inhaled corticosteroids (ICS) are generally reserved for patients with a documented response or those who have severe COPD with frequent exacerbations.

Table 2. Major differences between COPD management and asthma management in adults

Asthma	COPD
Regular ICS treatment is recommended for patients of all ages with persistent asthma.	ICS are generally reserved for patients with severe disease and frequent exacerbations, or those who have shown improvement with ICS therapy.1
Anticholinergic agents (e.g. tiotropium, ipratropium) are not used.	Tiotropium 18 mcg once daily improves dyspnoea, exacerbation rates, exercise capacity and health status.
Antibiotics are rarely indicated to manage exacerbations.	The use of antibiotics is often appropriate in the management of exacerbations.

Home oxygen therapy

Patients with COPD who have suspected chronic hypoxaemia should be assessed for home oxygen therapy.¹

• Long-term continuous oxygen therapy is appropriate for patients with consistent hypoxaemia.
• Intermittent oxygen therapy may be considered for patients with hypoxaemia on exertion, those living in isolated areas or prone to sudden life-threatening episodes while awaiting emergency care, and those travelling by plane.
• Nocturnal oxygen therapy is required for patients with hypoxaemia during sleep, and should be considered in patients with daytime somnolence, polycythaemia or right heart failure despite adequate daytime oxygenation.

For more information on home oxygen therapy, see Adult domiciliary oxygen therapy: Position statement of the Thoracic Society of Australia and New Zealand (PDF 248 KB).