title: Significance of interdialytic weight gain versus chronic volume overload: consensus opinion.
abstract: Predialysis volume overload is the sum of interdialytic weight gain (IDWG) and residual postdialysis volume overload. It results mostly from failure to achieve an adequate volume status at the end of the dialysis session. Recent developments in bioimpedance spectroscopy and possibly relative plasma volume monitoring permit noninvasive volume status assessment in hemodialysis patients. A large proportion of patients have previously been shown to be chronically volume overloaded predialysis (defined as >15% above 'normal' extracellular fluid volume, equivalent to >2.5 liters on average), and to exhibit a more than twofold increased mortality risk. By contrast, the magnitude of the mortality risk associated with IDWG is much smaller and only evident with very large weight gains. Here we review the available evidence on volume overload and IDWG, and question the use of IDWG as an indicator of 'nonadherence' by describing its association with postdialysis volume depletion. We also demonstrate the relationship between IDWG, volume overload and predialysis serum sodium concentration, and comment on salt intake. Discriminating between volume overload and IDWG will likely lead to a more appropriate management of fluid withdrawal during dialysis. Consensually, the present authors agree that this discrimination should be among the primary goals for dialysis caretakers today. In consequence, we recommend objective measures of volume status beyond mere evaluations of IDWG.
authors.affiliation: Department of Nephrology, Medical University of Vienna, Vienna, Austria.
authors.forename: Manfred
authors.initials: M
authors.lastname: Hecking
authors.forename: Angelo
authors.initials: A
authors.lastname: Karaboyas
authors.forename: Marlies
authors.initials: M
authors.lastname: Antlanger
authors.forename: Rajiv
authors.initials: R
authors.lastname: Saran
authors.forename: Volker
authors.initials: V
authors.lastname: Wizemann
authors.forename: Charles
authors.initials: C
authors.lastname: Chazot
authors.forename: Hugh
authors.initials: H
authors.lastname: Rayner
authors.forename: Walter H
authors.initials: WH
authors.lastname: Hörl
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Pisoni
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Robinson
authors.forename: Gere
authors.initials: G
authors.lastname: Sunder-Plassmann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Moissl
authors.forename: Peter
authors.initials: P
authors.lastname: Kotanko
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Levin
authors.forename: Marcus D
authors.initials: MD
authors.lastname: Säemann
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kalantar-Zadeh
authors.forename: Friedrich K
authors.initials: FK
authors.lastname: Port
authors.forename: Peter
authors.initials: P
authors.lastname: Wabel
mesh_terms: D058266:Dielectric Spectroscopy; D004039:Diet, Sodium-Restricted; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D010953:Plasma Volume; D006435:Renal Dialysis / Q000009:adverse effects*; D012964:Sodium / Q000097:blood; D012982:Sodium, Dietary; D014883:Water-Electrolyte Imbalance / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control; D015430:Weight Gain
chemical_list: D012982:Sodium, Dietary; D012964:Sodium