title: Sarcopenia correlates with systemic inflammation in COPD.
abstract: BACKGROUND
  Muscle wasting and chronic inflammation are predominant features of patients with COPD. Systemic inflammation is associated with an accelerated decline in lung function. In this study, the prevalence of sarcopenia and the relationships between sarcopenia and systemic inflammations in patients with stable COPD were investigated.
  
  
  METHODS
  In a cross-sectional design, muscle strength and muscle mass were measured by handgrip strength (HGS) and bioelectrical impedance analysis in 80 patients with stable COPD. Patients (≥40 years old) diagnosed with COPD were recruited from outpatient clinics, and then COPD stages were classified. Sarcopenia was defined as the presence of both low muscle strength (by HGS) and low muscle mass (skeletal muscle mass index [SMMI]). Levels of circulating inflammatory biomarkers (IL-6 and high-sensitivity TNFα [hsTNFα]) were measured.
  
  
  RESULTS
  Sarcopenia was prevalent in 20 (25%) patients. Patients with sarcopenia were older, had lower body mass index, and a higher percentage of cardiovascular diseases. In addition, they had significantly higher modified Medical Research Council scores and lower 6-minute walk distance than those without sarcopenia. HGS was significantly correlated with age, modified Medical Research Council score, and COPD Assessment Test scores. Both HGS and SMMI had associations with IL-6 and hsTNFα (HGS,r=-0.35,P=0.002; SMMI,r=-0.246,P=0.044) level. In multivariate analysis, old age, lower body mass index, presence of cardiovascular comorbidities, and higher hsTNFα levels were significant determinants for sarcopenia in patients with stable COPD.
  
  
  CONCLUSIONS
  Sarcopenia is very common in patients with stable COPD, and is associated with more severe dyspnea-scale scores and lower exercise tolerance. Systemic inflammation could be an important contributor to sarcopenia in the stable COPD population.
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, Gangnam Severance Hospital.
authors.forename: Min Kwang
authors.initials: MK
authors.lastname: Byun
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, Gangnam Severance Hospital.
authors.forename: Eun Na
authors.initials: EN
authors.lastname: Cho
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Joon
authors.initials: J
authors.lastname: Chang
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, Gangnam Severance Hospital.
authors.forename: Chul Min
authors.initials: CM
authors.lastname: Ahn
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, Gangnam Severance Hospital.
authors.forename: Hyung Jung
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D015897:Comorbidity; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D017079:Exercise Tolerance; D005260:Female; D018737:Hand Strength; D006304:Health Status; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D018836:Inflammation Mediators / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018482:Muscle, Skeletal / Q000503:physiopathology; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D055948:Sarcopenia / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D000070857:Walk Test
chemical_list: D015415:Biomarkers; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha
keywords: COPD; handgrip strength; muscle wasting; sarcopenia; systemic inflammation