title: What is the impact of impaired left ventricular ejection fraction in COPD after adjusting for confounders?
abstract: BACKGROUND
  It remains unknown whether and to what extent impaired left ventricular ejection fraction (LVEF) affects physical and psychological status in COPD. We aimed to compare health outcome measures between COPD patients with and without impaired LVEF after adjusting for age, sex, BMI and FEV1.
  
  
  METHODS
  Impaired LVEF was defined as values <50%. 85 COPD patients with impaired LVEF and 85 COPD patients with normal LVEF were matched for sex, age, BMI and FEV1. Exercise capacity, quadriceps muscle function, functional mobility, inflammatory status, health status, care dependency, and mood disorders were cross-sectionally assessed.
  
  
  RESULTS
  Patients with impaired LVEF had shorter 6-minute walk distance (mean -59 (95% confidence interval: -94, -25)m), lower symptom-limited peak oxygen uptake (-131 (-268, 7)ml/min), weaker quadriceps muscles (-12 (-20, -3)Nm) and had more symptoms of anxiety (+2 (1, 3) points) and depression (+1 (0, 2) points) than those with normal LVEF (all P<0.05). Health status was not statistically different between groups (P>0.05).
  
  
  CONCLUSIONS
  Impaired LVEF has a clear impact on physical and psychological status in patients with COPD, even after adjusting for confounders. This reinforces the importance of assessing and treating cardiac problems in COPD.
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands; Department of Respiratory Medicine, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands. Electronic address: rafaelmesquita14@ymail.com.
authors.forename: Rafael
authors.initials: R
authors.lastname: Mesquita
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands.
authors.forename: Frits M E
authors.initials: FM
authors.lastname: Franssen
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands.
authors.forename: Sarah
authors.initials: S
authors.lastname: Houben-Wilke
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands; Department of Cardiology, Maastricht University Medical Center + (MUMC+), Maastricht, The Netherlands.
authors.forename: Nicole H M K
authors.initials: NH
authors.lastname: Uszko-Lencer
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands; Department of Respiratory Medicine, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands.
authors.forename: Lowie E G W
authors.initials: LE
authors.lastname: Vanfleteren
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands.
authors.forename: Yvonne M J
authors.initials: YM
authors.lastname: Goërtz
authors.affiliation: Laboratory of Research in Respiratory Physiotherapy, Department of Physiotherapy, State University of Londrina (UEL), Londrina, Brazil.
authors.forename: Fabio
authors.initials: F
authors.lastname: Pitta
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands; Department of Respiratory Medicine, Maastricht University Medical Center+ (MUMC+), Maastricht, The Netherlands.
authors.forename: Emiel F M
authors.initials: EF
authors.lastname: Wouters
authors.affiliation: Department of Research & Education, CIRO, Horn, The Netherlands.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Spruit
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000368:Aged; D015986:Confounding Factors, Epidemiologic; D003430:Cross-Sectional Studies; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology; D013318:Stroke Volume / Q000502:physiology*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology; D016277:Ventricular Function, Left / Q000502:physiology*; D000070857:Walk Test / Q000379:methods
keywords: Chronic heart failure; Chronic obstructive pulmonary disease; Comorbidity; Outcome assessment (health care)