The typical asthmatic patient presents in childhood with wheeze or cough and has exacerbations associated with certain triggers, including infection. Between exacerbations lung function returns to normal or near normal and the condition may go into remission for several years, especially in the late teens and early 20s. There is often a family history of asthma or atopy, and the patient often has other atopic traits such as hay fever or eczema.

The typical COPD patient presents after many years of cigarette smoking. The symptom is more often breathlessness than wheeze and there is a significant obstructive pattern to lung function that does not return to normal even with remission of symptoms. Radiological imaging may show emphysema.

Historically, asthma was treated with beta-adrenergic agonists supplemented with inhaled corticosteroids. Antimuscarinic agents are generally less effective. Theophyllines have become unfashionable and leukotriene antagonists are occasionally useful. The treatments for COPD were largely the same as for asthma, although results were less satisfactory, particularly regarding impact on lung function tests.

While typical cases of asthma or COPD are easy to distinguish, some patients may exhibit features of both conditions. For examples, an asthmatic who smokes or is exposed to environmental pollution may develop irreversible airways obstruction similar to COPD. Some patients with clinical COPD have surprising improvement in lung function following stabilisation with treatment. These patients have sometimes been described as having an ‘overlap syndrome’.¹

While there was always academic debate about the distinction between asthma and COPD for practical clinical purposes, this was not particularly important since the treatments were largely the same. Recent developments and two important sets of guidelines^2,3 have changed this.

The GINA guidelines for asthma² recommend inhaled corticosteroids (ICS) as firstline treatment with inhaled short-acting beta-agonists for symptom relief as needed. With increasing severity long-acting beta-agonist (LABA) and ICS combinations are recommended. Long-acting antimuscarinic (LAMA) drugs are less useful for asthma and are third or fourth line choices.

The GOLD guidelines for COPD³ recommend LAMA for firstline treatment and there is now good evidence supporting their use with improvements in lung function, exercise tolerance and less frequent exacerbations. LABA/LAMA combinations are recommended for second line treatment and other interventions such as influenza and pneumococcal vaccination and rehabilitation programmes are recognised as being more effective than drug treatment at reducing COPD morbidity. Inhaled corticosteroids are not indicated for COPD and may be associated with increased severity of infections should they occur.

These guidelines indicate quite distinct and different forms of treatment for asthma and COPD and attention should be given to precise diagnosis. Where there is an apparent overlap syndrome it makes sense to treat the predominant pattern of disease – asthma or COPD – and move to the alternative diagnosis as second line treatment. Thus for COPD predominant cases start with LAMA or LAMA/LABA and add ICS if the response is poor. Similarly for asthma start with ICS and add LABA and LAMA later, monitoring lung function response.

References

1. Postma DS et al. The asthma-COPD overlap syndrome. N Engl J Med 2015;373:1241-9
2. Global Initiative for Asthma. Global strategy for asthma management and prevention (updated 2015); www.ginasthma .org/ local/ uploads/ files/ GINA_Report_2015_May19.pdf
3. Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease (updated 2015), www.goldcopd.org/uploads/users/files/GOLD_Report_2015_Apr2.pdf