Differences between asthma and COPD: how to make the diagnosis in primary care

Chronic obstructive pulmonary disease (COPD) and asthma are common, are frequently confused, and are both underdiagnosed and misdiagnosed. Early and accurate diagnosis is essential because in spite of similarities in presentation, they merit different treatment: Disease-focused early intervention may both improve short-term health status and decrease future risk of events such as exacerbations and disease progression.
Lung-function assessment meeting international standards, combined with a thorough patient medical history, including age, symptoms, smoking status, and other comorbidities such as atopy, is an essential element of accurate differential diagnosis. A number of additional tests and tools may be helpful in the differential diagnosis, including both questionnaires specifically developed to discriminate between COPD and asthma and novel technologies such as exhaled nitric oxide or induced sputum. After the initial or provisional diagnosis has been established, it is necessary to monitor patients to confirm the diagnosis in terms of clinical response. This is particularly important when the diagnosis is less clear-cut, such as in younger individuals or in those with asthma or atopic histories with fixed airways obstruction. In addition, a double diagnosis can be considered in the minority of individuals with fixed airways obstruction and both asthmatic features and a relevant smoking history.