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.