title: Measuring body composition in chronic heart failure: a comparison of methods.
abstract: OBJECTIVE
  Fat-free mass (FFM) is increasingly recognized as a systemic marker of disease severity in chronic organ failure and is an important target for physiologic and pharmacologic interventions to improve functional status. The aim of this study was therefore to evaluate two clinical methods to assess FFM in patients with chronic heart failure (CHF) using deuterium dilution (DEU) as reference and bromide dilution to assess the ratio between intracellular (ICW) and extracellular water (ECW) as potential confounder.
  
  
  METHODS
  Body composition was measured with dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA) and DEU in 22 stable patients from our heart failure outpatient clinic and 24 healthy age matched controls.
  
  
  RESULTS
  FFM values measured by DXA and DEU in patients (r = 0.92, SEE: 3.1 kg) and controls (r = 0.99, SEE: 1.3 kg) were strongly related. In both patients and controls, the inter method difference increased with higher values of FFM (DXA overestimating DEU). The ICW/ECW ratio was within the normal range and comparable between the groups. In patients, a highly significant correlation coefficient was found (r = 0.93, SEE 2.1 p = 0.01) between total body water (DEU) and height squared/resistance (Ht2/R). On multiple regression next to Ht2/R, body weight was an independent predictor of FFM(DEU) (r = 0.95, SEE 2.5 kg, p<0.001; TBWdeu = 0.528 Ht2/R + (0.182 weight) + 8.277).
  
  
  CONCLUSIONS
  DXA and DEU are appropriate and interchangeable laboratory methods for assessment of FFM in clinically stable heart failure patients, however, overestimation of FFM(DXA) should be considered. BIA is a suitable clinical alternative for diagnostic purposes.
authors.affiliation: Department of Respiratory Medicine, University Hospital Maastricht, The Netherlands. n.lencer@cardio.azm.nl
authors.forename: Nicole H M K
authors.initials: NH
authors.lastname: Uszko-Lencer
authors.forename: Francien
authors.initials: F
authors.lastname: Bothmer
authors.forename: Petra E J
authors.initials: PE
authors.lastname: van Pol
authors.forename: Annemie M W J
authors.initials: AM
authors.lastname: Schols
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000368:Aged; D001823:Body Composition; D001835:Body Weight; D016022:Case-Control Studies; D002908:Chronic Disease; D003903:Deuterium; D017097:Electric Impedance; D005080:Exercise Test; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D007201:Indicator Dilution Techniques; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D013318:Stroke Volume / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000150:complications
chemical_list: D003903:Deuterium