Chronic obstructive pulmonary disease and comorbidity: possible implications in the disease management

Chronic obstructive pulmonary disease (COPD) is becoming the first cause of pulmonary disability and death. Because of the increase in the mean age of the population, COPD is frequently associated with important comorbidities that require medical attention. In the last 10 years many observational studies (large surveys of population or databases of the main health organisations or of General Practitioners in different Countries) have extensively documented that many diseases (cardiovascular diseases, metabolic syndrome, osteoporosis, diabetes, depression, and lung cancer) have a higher prevalence in COPD patients than in non-COPD ones (after correction for many confounding factors, such as smoking habit). There are two different views relating the association between COPD and comorbidities. These comorbidities may be just randomly associated with COPD (due to common risk factors including age), but many data support the hypothesis that chronic inflammation derived from airway wall and lung parenchima of COPD patients may "spill over" the systemic circulation and mediate, at least partially, negative effects on other organs or systems. Some comorbidities seem more commonly associated with the functional abnormalities of COPD (like skeletal muscle dysfunction and malnutrition, or osteoporosis, which are related to the inactivity due to dyspnoea), while for others the systemic effect of some cytokines (IL-6,TNFalfa, etc.) or mediators (CRP, serum amyloid A, etc.) may play a role.Since comorbidities represent major causes of death in COPD patients, and are responsible of poorer quality of life and hospitalisation during COPD exacerbations, their presence requires a new approach, including an interdisciplinary co-operation and the use of specific strategies able to affect the several pulmonary and extra-pulmonary components of the disease. New pharmacologic options (such as roflumilast) active on both pulmonary and extra-pulmonary inflammation might be useful in the future