Towards individualised medicine for airways disease: identifying clinical phenotype groups.

Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous diseases [1, 2]. In diagnosing a patient with asthma or COPD, an individual is thereby lumped together with other patients whose disease phenotype and response to treatment may be quite different. Doing so simplifies treatment guidelines and facilitates the application of evidence-based medicine but there is a risk that interventions that could provide benefit to certain disease subgroups are overlooked. At present, it is not known to what degree splitting of airways disease groups can lead to improved health outcomes and this question remains a focus of intense research. The approach in recent years has been to re-examine the classification of airways disease to identify disease subgroups that may respond to treatments in different ways.