Prevalence and burden of comorbidities in chronic obstructive pulmonary disease

Department of Respiratory Medicine, State University of Medicine and Pharmacy “Nicolae Testemitanu”, Stefan cel Mare Street 165, 2004 Chisinau, Republic of Moldova Chest Centre, Aintree University Hospitals NHS Foundation Trust, Langmoor Lane, Liverpool, Merseyside L9 7AL, United Kingdom University General Hospital, Department of Thoracic Medicine, Stavrakia, 71110 Heraklion, Crete, GreeceThe classical definition of Chronic Obstructive Pulmonary Disease (COPD) as a lung condition characterized by irreversible airway obstruction is outdated. The systemic involvement in patients with COPD, as well as the interactions between COPD and its comorbidities, justify the description of chronic systemic inflammatory syndrome. The pathogenesis of COPD is closely linked with aging, as well as with cardiovascular, endocrine, musculoskeletal, renal, and gastrointestinal pathologies, decreasing the quality of life of patients with COPD and, furthermore, complicating the management of the disease. The most frequently described comorbidities include skeletal muscle wasting, cachexia (loss of fat-free mass), lung cancer (small cell or non-small cell), pulmonary hypertension, ischemic heart disease, hyperlipidemia, congestive heart failure, normocytic anemia, diabetes, metabolic syndrome, osteoporosis, obstructive sleep apnea, depression, and arthritis. These complex interactions are based on chronic low-grade systemic inflammation, chronic hypoxia, and multiple common predisposing factors, and are currently under intense research. This review article is an overview of the comorbidities of COPD, as well as their interaction and influence on mutual disease progression, prognosis, and quality of life