Extrapulmonary Comorbidities in COPD: A Bidirectional and Multimorbid Perspective

INTRODUCTIONChronic obstructive pulmonary disease (COPD) is a non-homogeneous pulmonary disease characterized by chronic symptoms (dyspnea, cough, sputum, and/or exacerbations) due to abnormalities of the airways and/ or alveoli that cause persistent, often progressive, airflow obstruction. 1 However, COPD cannot be defined in a single sentence.Even though new evidence has emerged, COPD requires further research from aetiology to classification and from diagnosis to treatment.COPD is a disease, or more accurately a syndrome, that cannot be explained by a single mechanism and involves numerous gene-environment interactions and many confounding factors, such as comorbidities.COPD, the third-most common cause of mortality, carries a high comorbidity burden owing to shared aetiological factors and pathophysiological characteristics. 2 Comorbidities are important in COPD because they increase the risk of exacerbation and mortality.3 The majority of mild-to-moderate COPD patients die from non-respiratory causes.4 Today, COPD is recognised as a multimorbid disease.Comorbidities, which are increasingly emphasised in GOLD reports, are important because they share a common aetiology with COPD and contribute to difficulties in disease management.An understanding of comorbidities requires a multifaceted perspective.Just as we consider the impact of comorbidities on COPD, specialists in other fields also consider Chronic obstructive pulmonary disease (COPD) remains among the leading causes of death.The systemic characteristics of COPD are becoming clearer every day, and the importance of comorbidities is increasingly well understood.Comorbidities are one of the main causes of mortality in COPD.Although there are specific guidelines for each disease, there is limited literature explaining the effects of comorbidities on one another.Non-respiratory comorbidities associated with mortality in COPD include cardiovascular disease (CVD), metabolic, musculoskeletal, and psychiatric disorders.Both COPD and these comorbid conditions share a common aetiology and are associated with complex clinical and therapeutic interactions.CVD and metabolic comorbidities are more symptomatic and can be easily recognised by patients and physicians.However, osteoporosis, anxiety, and depression are often asymptomatic, despite the fact that these are more common than other comorbidities.Current data suggest that diagnosis and treatment of comorbidities improve prognosis in COPD.Instead of focusing solely on COPD treatment, we should adopt a holistic approach to patient care.This narrative review aims to summarise the bidirectional relationships between COPD and its most common fatal extrapulmonary comorbidities.Another aim of the study is to compile a substantial body of scattered information to provide clinicians with an overview.