IntroductionOver the past 60 years we have witnessed radical transformations in population demographics and the burden of diseases that are shaping health care and which have an immediate and future impact within the field of respiratory diseases. Despite improvements in life expectancy and lower death rates in the United States over this period, COPD rose to the third leading cause of death in 2008, a testament to the growing importance of chronic diseases and disability.1 Refinements in the understanding of the pathophysiology and mechanisms responsible for susceptibility and heterogeneity of COPD (reviewed in other articles in the same issue of this journal) have occurred over the past 10 years. The search for additional ways to modify important outcomes has been enriched by two separate but related concepts that, at the turn of the century, were not always part of the mainstream
AbstractChronic obstructive pulmonary disease (COPD) is a disease of aging in combination with genetic, environmental, and behavioral risk factors. Aging and many of these risk factors are shared with other diseases, and, as a result, it is not surprising that patients with COPD often have coexistent diseases. This review of COPD comorbidities uses a framework in which coexistent diseases are considered important comorbidities if they are more frequent, have more severe consequences, influence the progression and outcomes of COPD, or are clustered together into proposed phenotypes, supplemented by a framework in which certain comorbidities are expected to share specific pathogenic mechanisms. This review explores classic COPD comorbidities such as cardiovascular disease, cachexia and sleep apnea, but also looks at more recently described comorbidities, such as gastroesophageal reflux, osteoporosis and depression/anxiety. understanding of the disease. The first one is that the degree of obstruction -which defines the disease and its severity -does not fully correlate with COPD outcomes (exacerbations, death, and health-related quality-of-life [HR-QOL]). 2,3 The second is that a bidirectional interplay exists between the persistent inflammatory processes damaging the lungs and other organs. As a result, COPD is a complex disease linked with other comorbidities that influences treatment effectiveness and outcomes. This paper presents a review of the importance of COPD comorbidities in the development, progression, prognosis and therapy of COPD, and identifies the gaps in knowledge and research in this area.
Challenges in the Identification and Interpretation of COPD ComorbiditiesIn the United States, COPD patients are usually older adults who have a history of tobacco exposure. These traits are shared with other chronic conditions, including cardiovascular disease and cancer. The typical patient with COPD reports, on average, 4 or more additional diseases 4 and on any given day one-third of COPD patients use 5-10 different medications. 5 There are several different frameworks that can help to decide if the relevance of a coexistent dise...