title: The impact of hydration status on the assessment of lean body mass by body electrical impedance in dialysis patients.
abstract: The impact of hydration status on body composition analysis in hemodialysis (HD) and peritoneal dialysis (PD) patients was assessed. Twenty-seven HD patients and 42 PD patients were divided into three groups according to their (postdialytic) hydration status as measured by segmental bioelectrical impedance analysis (BIA): normohydrated, dehydrated, or overhydrated. Fifty-six percent of the PD patients and 74% of the HD patients appeared to be normohydrated. Lean body mass (LBM) was calculated in all subjects from skinfold anthropometric (SA) measurements and from whole body BIA data. LBM-SA and LBM-BIA did not differ in normohydrated patients and correlated well with each other (r = 0.88). In overhydrated subjects BIA overestimated LBM compared to SA; in the dehydrated group BIA tended to underestimate LBM. The correlation between LBM-SA and LBM-BIA was poor in both groups. It can be concluded that hydration status has a major influence on BIA-based LBM measurements. Reliable LBM figures can only be obtained when patients are at their ideal dry weight.
authors.affiliation: Free University Hospital, Amsterdam, The Netherlands.
authors.forename: C W
authors.initials: CW
authors.lastname: de Fijter
authors.forename: M M
authors.initials: MM
authors.lastname: de Fijter
authors.forename: L P
authors.initials: LP
authors.lastname: Oe
authors.forename: A J
authors.initials: AJ
authors.lastname: Donker
authors.forename: P M
authors.initials: PM
authors.lastname: de Vries
mesh_terms: D000328:Adult; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water / Q000378:metabolism*; D017097:Electric Impedance; D006801:Humans; D008875:Middle Aged; D010530:Peritoneal Dialysis; D006435:Renal Dialysis