title: Biomarkers of systemic inflammation and depression and fatigue in moderate clinically stable COPD.
abstract: BACKGROUND
  COPD is an inflammatory disease with major co-morbidities. It has recently been suggested that depression may be the result of systemic inflammation. We aimed to explore the association between systemic inflammation and symptoms of depression and fatigue in patients with mainly moderate and clinically stable COPD using a range of inflammatory biomarkers, 2 depression and 2 fatigue scales.
  
  
  METHODS
  We assessed 120 patients with moderate COPD (FEV1% 52, men 62%, age 66). Depression was assessed using the BASDEC and CES-D scales. Fatigue was assessed using the Manchester COPD-fatigue scale (MCFS) and the Borg scale before and after 6MWT. We measured systemic TNF-α, CRP, TNF-α-R1, TNF-α-R2 and IL-6.
  
  
  RESULTS
  A multivariate linear model of all biomarkers showed that TNF-α only had a positive correlation with BASDEC depression score (p = 0.007). TNF-α remained positively correlated with depression (p = 0.024) after further adjusting for TNF-α-R1, TNF-α-R2, 6MWD, FEV1%, and pack-years. Even after adding the MCFS score, body mass and body composition to the model TNF-α was still associated with the BASDEC score (p = 0.044). Furthermore, patients with higher TNF-α level (> 3 pg/ml, n = 7) had higher mean CES-D depression score than the rest of the sample (p = 0.03). Borg fatigue score at baseline were weakly correlated with TNF-α and CRP, and with TNF-α only after 6MWT. Patients with higher TNF-α had more fatigue after 6MWD (p = 0.054).
  
  
  CONCLUSIONS
  This study indicates a possible association between TNF-α and two frequent and major co-morbidities in COPD; i.e., depression and fatigue.
authors.affiliation: University of Manchester, Manchester Academic Health Sciences Centre, University Hospital of South Manchester Foundation Trust, Wythenshawe, Manchester, UK. alshair02@yahoo.com
authors.forename: Khaled
authors.initials: K
authors.lastname: Al-shair
authors.forename: Umme
authors.initials: U
authors.lastname: Kolsum
authors.forename: Rachel
authors.initials: R
authors.lastname: Dockry
authors.forename: Julie
authors.initials: J
authors.lastname: Morris
authors.forename: Dave
authors.initials: D
authors.lastname: Singh
authors.forename: Jørgen
authors.initials: J
authors.lastname: Vestbo
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D015897:Comorbidity; D003863:Depression / Q000453:epidemiology* / Q000276:immunology / Q000523:psychology; D004739:England / Q000453:epidemiology; D005221:Fatigue / Q000453:epidemiology* / Q000276:immunology / Q000523:psychology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation / Q000453:epidemiology* / Q000276:immunology / Q000523:psychology; D018836:Inflammation Mediators / Q000097:blood*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology / Q000523:psychology; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators