COPD is a common lung disease responsible for significant disability. It is a common cause of hospitalisation and death. In Australia it is under diagnosed and often over or even undertreated. Primarily a lung disease, it has extrapulmonary manifestations and is frequently associated with respiratory and non-respiratory comorbidities all of which can influence symptoms and outcomes.
Spirometry is the essential test in diagnosing COPD. There is no other way of demonstrating airflow limitation and so confirming COPD.
Barriers to performing spirometry are rarely insurmountable, even with the current COVID pandemic. The demonstration of irreversible airflow limitation on spirometry (post bronchodilator FEV1/FVC ratio <0.7) in the presence of a history of cigarette smoking (more than 10 pack years) or other contributors such as air pollution makes a diagnosis of COPD likely. The degree of airflow limitation, however, is not a reliable predictor of symptom severity in COPD.
Further assessment for defining the severity of COPD depends on measuring the severity of symptoms. This includes exercise tolerance (modified Medical Research Council [mMRC] scale), general COPD symptoms (COPD Assessment Test score [www.catestonline.org]) and exacerbation frequency (≥ two exacerbations or ≥ 1 severe).
This allows a consideration of potential symptoms of exertional dyspnoea, cough, general fatigue, exacerbation risk with a view to directing therapy. Appropriate choice of pharmacological therapy lowers likelihood of overtreatment or unnecessary treatment.
Chest radiology is helpful insofar as identifying comorbid respiratory conditions (e.g. emphysema, fibrosis, lung nodules or bronchiectasis). It is not sufficient to make the diagnosis alone.
Other investigations can be helpful in assessing extra pulmonary disease (e.g. cardiovascular disease, osteoporosis, type two diabetes, hypertension). These can be done depending on the clinical picture and likelihood of the presence of other diseases. As with the assessment of any respiratory disease, smoking cessation is imperative as it is the only intervention with clear positive impact on disease progression.
Initial COPD management includes a combination of pharmacological and nonpharmacological strategies.
Patient education of COPD is vital, so people understand what they have and what treatment is for. Up-to-date vaccinations for flu, pneumococcus and COVID can help reduce exacerbation frequency and severity. Exercise helps maintain fitness and weight control. This can be incorporated into a pulmonary rehabilitation program although there are several administrative barriers to this (referral usually needs to be from a specialist or hospital).
Pharmacological therapy can improve symptoms, quality of life, and reduce exacerbation risk but there’s no reliable evidence of a positive impact on disease progression or overall mortality.
Therapy needs to be targeted to the symptoms to be treated. Generally, all patients will complain of breathlessness so generally all patients will benefit from bronchodilator therapy. Local guidelines (copdx.org.au) detail the initiation of bronchodilator therapy but generally for someone who is symptomatic most of the time either a regular long-acting beta agonist (LABA) or long-acting muscarinic antagonist (LAMA) is indicated. If symptoms persist, adding the alternative bronchodilators so they’re on dual therapy (LABA/LAMA) is indicated.
Mostly bronchodilator therapy does not lead to a sudden increase in lung function or reduction in symptoms but many of the benefits (quality of life) are over longer term.
In initial pharmacological management of COPD, there is little role for inhaled corticosteroids (ICS). They have a role to play in the patient with frequent exacerbations despite dual bronchodilator therapy but at a lower dose than usually used for asthma. Long-term ICS use still has the risk of long-term steroid side effects (e.g. cataracts, bone density, infection). Given the significant co-morbidities for COPD patients, the risk and benefits of ICS therapy needs to be assessed.
Diagnosing COPD with the appropriate smoking history can be straightforward but a proportion of patients will have asthma-COPD overlap and this may require more specialist investigation to confirm the diagnosis and ensure appropriate therapy. This may be considered if there is prior history of asthma and a history of significant smoking or if there are asthma features at presentation (variable symptoms, bronchodilator response on spirometry).
Tailored therapy can provide optimal outcomes while avoiding undertreatment and poor disease control or overtreatment with potentially significant side effects.
Author competing interest – nil