GINA strategy 2020: asthma–COPD overlap

 

Table 1: Current definitions of asthma and COPD, and clinical description of asthma-COPD overlap

Asthma

Asthma is a heterogeneous disease, usually characterised by chronic airway inflammation. It is defined by the history of respiratory symptoms such as wheeze, shortness of breath, chest tightness and cough that vary over time and in intensity, together with variable expiratory airflow limitation. [GINA 2020]

COPD

Chronic obstructive pulmonary disease (COPD) is a common, preventable and treatable disease that is characterised by persistent respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases and influenced by host factors including abnormal lung development. [GOLD 2020]

Asthma–COPD overlap, also called asthma+COPD

‘Asthma-COPD overlap’ and ‘asthma+COPD’ are terms used to collectively describe patients who have persistent airflow limitation together with clinical features that are consistent with both asthma and COPD. This is not a definition of a single disease entity, but a descriptive term for clinical use that includes several different clinical phenotypes reflecting different underlying mechanisms.

Assessment and management of patients with chronic respiratory symptoms

1: History and clinical assessment to establish the following:

• the nature and pattern of respiratory symptoms (variable and/or persistent)
• history of asthma diagnosis; childhood and/or current
• exposure history: smoking and/or other exposures to risk factors for COPD.

The features that are most helpful in identifying and distinguishing asthma from COPD, and the features that should prompt a patient to be treated as asthma to reduce the risk of severe exacerbations and death, are shown in Algorithm 1.

Caution: consider alternative diagnoses: other airways diseases, such as bronchiectasis and chronic bronchitis, and other forms of lung disease such as interstitial lung disease may present with some of the above features. The approach to diagnosis provided here does not replace the need for a full assessment of patients presenting with respiratory symptoms, to first exclude non-respiratory diagnoses such as heart failure. Physical examination may provide supportive information.

Algorithm 1: Approach to initial treatment in patients with asthma and/or COPD

2. Spirometry is essential to confirm the following:

• the presence of persistent expiratory airflow limitation
• variable expiratory airflow limitation.

Spirometry is preferably performed at the initial assessment. In cases of clinical urgency it may be delayed to a subsequent visit, but confirmation of diagnosis may be more difficult once patients are started on ICS-containing therapy (see Box1–3 in the full GINA report). Early confirmation (or exclusion) of the presence of persistent expiratory airflow limitation may avoid needless trials of therapy, or delays in initiating other investigations. Spirometry can confirm both persistent airflow limitation and reversibility (see Algorithm 1 and Table 2).

Measurement of peak expiratory flow (PEF), if performed repeatedly on the same meter over a period of one to two weeks, may help to confirm reversible airflow limitation and the diagnosis of asthma by demonstrating excessive variability. However, PEF is not as reliable as spirometry, and a normal PEF does not rule out either asthma or COPD.

Table 2: Spirometric measures in asthma and COPD

Spirometric variable	Asthma	COPD	Asthma+COPD
Normal FEV1/FVC pre- or post-BD	Compatible with asthma	No compatible with COPD	Not compatible
Reduced post-BD FEV1/FVC (< lower limit of normal, or <0.7 (GOLD))	Indicates airflow limitation but may improve spontaneously or on treatment	Required for diagnosis of COPD	Required for diagnosis of asthma+COPD
Post-BD FEV1 ≥80% predicted	Compatible with diagnosis of asthma (good asthma control or interval between symptoms)	Compatible with mild persistent airflow limitation if post-PD FEV1/FVC is reduced	Compatible with mild persistent airflow limitation if post-PD FEV1/FVC is reduced
Post-PD FEV1  <80% predicted	Compatible with diagnosis of asthma. Risk factor for asthma exacerbations	An indicator of severity of airflow limitation and risk of future events (e.g. mortality and COPD exacerbations)	As for COPD and asthma
Post-BD increase in FEV1 ≥12% and 200 ml from baseline (reversible airflow limitation)	Usual at some time in course of asthma, but may not be present when well-controlled or on controller therapy	Common and more likely when FEV1 is low	Common and more likely when FEV1 is low
Post-BD increase in FEV1  >12% and 400 ml from baseline (marked reversibility)	High probability of asthma	Unusual in COPD	Compatible with asthma+COPD
Abbreviations: BD=bronchodilator; FEV1 =forced volume in one second; FVC= forced vital capacity; GOLD=Global Initiative for Obstructive Lung Disease.

3: Selecting initial treatment (See Algorithm 1)

For asthma

Commence treatment as described in Chapter 3 of the full report. Pharmacotherapy is based on ICS to reduce the risk of severe exacerbations and death and to improve symptom control, with add-on treatment as required, e.g. add-on LABA and/or LAMA.

As-needed low dose ICS-formoterol may be used as the reliever, on its own in mild asthma or in addition to maintenance ICS-formoterol in patients with moderate-severe asthma prescribed maintenance and reliever therapy (see Box 3-5A in the full report). Inhaled therapy should be optimised to minimise the need for oral corticosteroids (OCS).

For COPD

Commence treatment as in the current GOLD strategy report. Pharmacotherapy starts with symptomatic treatment with long-acting bronchodilators (LABA and/or LAMA). ICS may be added as per GOLD for patients with hospitalisations, ≥2 exacerbations/year requiring OCS, or blood eosinophils ≥300/μL, but is not used alone as monotherapy without LABA and/or LAMA. Inhaled therapy should be optimised to reduce the need for OCS.

In patients with features of COPD, high dose ICS should be avoided because of the risk of pneumonia.

For patients with features of asthma and COPD

Start treatment as for asthma (see Box 3-4, A–D in the full report) until further investigations have been performed.

ICS play a pivotal role in preventing morbidity and even death in patients with uncontrolled asthma symptoms, for whom even seemingly ‘mild’ symptoms (compared to those of moderate or severe COPD) might indicate significant risk of a life-threatening attack. For patients with asthma+COPD, ICS should be used initially in a low or medium dose (see Box 3-6 of the full report), depending on level of symptoms and risk of adverse effects, including pneumonia.

Patients with features or diagnosis of both asthma and COPD will usually also require add-on treatment with LABA and/or LAMA to provide adequate symptom control.

Patients with any features of asthma should not be treated with LABA and/or LAMA alone, without ICS.

All patients with chronic airflow limitation

Provide advice, as described in the GINA and GOLD reports, about:

• treatment of modifiable risk factors including advice about smoking cessation
• treatment of comorbidities
• non-pharmacological strategies including physical activity, and, for COPD or asthma-COPD overlap, pulmonary rehabilitation and vaccinations
• appropriate self-management strategies
• regular follow-up.

In a majority of patients, the initial management of asthma and COPD can be satisfactorily carried out at primary care level. However, both the GINA and GOLD strategy reports recommend referral for further diagnostic procedures at relevant points in patient management (see below). This may be particularly important for patients with features of both asthma and COPD, given that this is associated with worse outcomes and greater healthcare utilisation.

4: Referral for specialised investigations (if necessary)

Referral for expert advice and further diagnostic evaluation is advised in the following contexts:

• patients with persistent symptoms and/or exacerbations despite treatment
• diagnostic uncertainty, especially if an alternative diagnosis (e.g. bronchiectasis, post-tuberculous scarring, bronchiolitis, pulmonary fibrosis, pulmonary hypertension, cardiovascular diseases and other causes of respiratory symptoms) needs to be investigated
• patients with suspected asthma or COPD in whom atypical or additional symptoms or signs (e.g. haemoptysis, significant weight loss, night sweats, fever, signs of bronchiectasis or other structural lung disease) suggest an additional pulmonary diagnosis. This should prompt early referral, without waiting form a trial of treatment for asthma or COPD
• when chronic airways disease is suspected but syndromic features of both asthma and COPD are few
• patients with comorbidities that may interfere with the assessment and management of their airways disease
• referral may also be appropriate for issues arising during ongoing management of asthma, COPD or asthma-COPD overlap, as outlined in the GINA and GOLD strategy reports.