Asthma and Chronic obstructive pulmonary disease (COPD) both have a high prevalence worldwide and yet each condition remains underdiagnosed. Despite a number of common features, these inflammatory respiratory syndromes have distinct clinical outcomes.

COPD represents a greater economic burden than asthma because it has a less favourable prognosis and is associated with greater morbidity and mortality.

Therefore, it is important to distinguish between these two diseases at an early stage, so that appropriate therapy can be prescribed to prevent deterioration. However, effective treatments that may be used in both conditions can minimise the effects of misdiagnosis and maximise the impact of treatment without the associated complexity when both conditions occur together.

The current review summarises the differences and similarities of asthma and COPD, in terms of risk factors, pathophysiology, symptoms and diagnosis, to provide greater understanding of the role of budesonide/formoterol in a single inhaler in both diseases.