Bronchiectasis: Phenotyping a Complex Disease.

Bronchiectasis is a long-neglected disease currently experiencing a surge in interest. It is a highly complex condition with numerous aetiologies, co-morbidities and a heterogeneous disease presentation and clinical course. The past few years have seen major advances in our understanding of the disease, primarily through large real-life cohort studies. The main outcomes of interest in bronchiectasis are symptoms, exacerbations, treatment response, disease progression and death. We are now more able to identify clearly the radiological, clinical, microbiological and inflammatory contributors to these outcomes. Over the past couple of years, multidimensional scoring systems such as the Bronchiectasis Severity Index have been introduced to predict disease severity and mortality. Although there are currently no licensed therapies for bronchiectasis, an increasing number of clinical trials are planned or ongoing. While this emerging evidence is awaited, bronchiectasis guidelines will continue to be informed largely by real-life evidence from observational studies and patient registries. Key developments in the bronchiectasis field include the establishment of international disease registries and characterisation of disease phenotypes using cluster analysis and biological data.