Treatment of COPD by clinical phenotypes: putting old evidence into clinical practice.

The new Global Initiative for Chronic Obstructive Lung Disease update has moved the principles of treatment of stable chronic obstructive pulmonary disease (COPD) forward by including the concepts of symptoms and risks into the decision of therapy. However, no mention of the concept of clinical phenotypes is included. It is recognised that COPD is a very heterogeneous disease and not all patients respond to all drugs available for treatment. The identification of responders to therapies is crucial in chronic diseases to provide the most appropriate treatment and avoid unnecessary medications. The classically defined phenotypes of chronic bronchitis and emphysema, together with the newly described phenotypes of overlap COPD-asthma and frequent exacerbator, allow a simple classification of patients that share clinical characteristics and outcomes and, more importantly, similar responses to existing treatments. These clinical phenotypes can help clinicians identify patients that respond to specific pharmacological interventions. For example, frequent exacerbators are the only subjects with an indication for anti-inflammatory treatment in COPD. Among them, those with chronic bronchitis are the only candidates to receive phosphodiesterase-4 inhibitors. Patients with overlap COPD-asthma phenotype show an enhanced response to inhaled corticosteroids and infrequent exacerbators should only receive bronchodilators. These well-defined clinical phenotypes could potentially be incorporated into treatment guidelines.