Chronic Obstructive Pulmonary Disease A Systemic Disease

For the first time, the recently published American Thoracic Society/European Respiratory Society chronic obstructive pulmonary disease (COPD) guidelines explicitly recognize that “although chronic obstructive pulmonary disease . . . affects the lungs, it also produces significant systemic consequences” (1). This is somewhat surprising because we have implicitly known for many years that COPD indeed has systemic consequences. For instance, since 1980, we have known that severe COPD can produce significant arterial hypoxemia (thus, presumably, some degree of “systemic” hypoxia) and that domiciliary oxygen therapy can improve survival in these patients without having any noticeable effect on lung function (2, 3). Likewise, for more than 30 years, we have been aware of the fact that some patients with COPD will develop weight loss and eventually cachexia (“pink puffers”), whereas others (“blue blotters”) will not (4). The former is clearly recognized now as a “systemic effect” of COPD (5, 6). So, what is really new in this field? I believe that what is novel is the realization that COPD is characterized by an abnormal inflammatory response of the lung parenchyma to the inhalation of particles and toxic fumes, mostly tobacco smoking (1), which can also be detected in peripheral blood, thus qualifying it as “systemic inflammation” (5, 6). We have now begun to uncover the origin and consequences of, and seek potential therapy for, this systemic inflammation in COPD, and we are beginning to appreciate that these discoveries may be of great relevance and lead to better management of patients with COPD (5, 6). This presentation first reviews the evidence supporting the presence of systemic inflammation in COPD, then discusses its potential origin and consequences, and finally, discusses potential therapeutic alternatives. Throughout the text, relevant questions, still unanswered, will be identified.