Affiliation: Chest Centre, Aintree University Hospitals NHS Foundation Trust, Lower Ln, Liverpool, Merseyside L9 7AL, UK.
Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of morbidity and mortality worldwide. Disease severity evaluation was based on airflow limitation for many years. However, it is now obvious that no single parameter can describe the complexity of COPD and a more holistic approach should be utilised. For this reason, newer classifications of the disease are based on multiple clinical characteristics or biomarkers that can predict different clinically meaningful outcomes, such as symptoms, frequency of exacerbations, progression of disease, response to different medications and mortality. Ongoing research highlights such biomarkers, while guidelines have already incorporated them, as the basis of clinical phenotypes. GOLD highlights the need for more intensive treatment of frequent exacerbators and COPD patients whose disease significantly burdens their quality of life. Moreover, a COPD-asthma overlap syndrome with a different prognosis and potentially different therapeutic approach is also recognised. Spanish guidelines also group frequent exacerbators to predominantly emphysematic versus predominantly bronchitic. Another approach aims to create scoring systems, or multidimensional indices, based on multiple biomarkers which evaluate different aspects of the disease. The recognition of all these prognostic and therapeutic patient subgroups lead to a more personalised approach to each patient and also provides data to the –omics to uncover the pathogenetic background of this diversity and develop new targeted treatments.