Mechanisms in chronic obstructive pulmonary disease: comparisons with asthma

The mechanisms underlying the pathogenesis and pathophysiology of COPD are complex and have been largely studied; however, the underlying factors are not completely understood. Chronic airway inflammation is a key characteristic of COPD and specific inflammatory abnormalities exist even in the airways of subjects with mild and asymptomatic clinical patterns. In addressing these mechanisms, a comparison with asthma becomes fundamental, since the latter shows clinical and functional aspects that overlap with those observed in COPD. The mechanisms of inflammation in COPD, and their similarities and differences with asthma are therefore discussed in this article. The diagnosis of chronic obstructive diseases may pose important issues regarding on the differentiation between COPD and asthma: lack of, or delayed, recognition of the disease (underdiagnosis), incorrect interpretation of symptoms that are attributed to other respiratory or non-respiratory diseases (misdiagnosis), and erroneous classification of healthy subjects as affected by the disease (overdiagnosis). Underdiagnosis, misdiagnosis and overdiagnosis may all lead to inappropriate therapeutic choices, thus affecting health-related quality of life and prognosis. In this scenario, specific issues accounting for differences between COPD and asthma are also addressed.