title: Pre-dialysis and post-dialysis hydration status and N-terminal pro-brain natriuretic peptide and survival in haemodialysis patients.
abstract: OBJECTIVE
  Many dialysis centres have no formal program for assessing and adjusting post-haemodialysis (HD) target weight. Apart from clinical assessment, there are bioimpedance devices and natriuretic peptides that could potentially aid clinical management. We wished to determine whether pre- or post-HD bioimpedance assessment of extracellular water (ECW) or N terminal probrain natriuretic peptide (NT-proBNP) affected patient outcomes.
  
  
  METHODS
  Multi-frequency bioimpedance assessments (MFBIA) were made before and after the midweek dialysis session, along with a post-dialysis NT-proBNP measurement.
  
  
  RESULTS
  Data from 362 patients, median age of 63 (50-76) years, 59.7% male, 41.2% Caucasoid, with a median dialysis vintage of 31.4 (13.5-61.7) months were available for review. During a median follow-up of 49.6 (21.9-50.2) months there were 110 (30.4%) deaths. Patients who died had significantly increased ECW, as % over-hydrated both pre-HD 6.6 (5.8-7.6)% vs. survivors 5.1 (4-6.6)%, and post-HD 5.1 (4-6.6)% vs. 0.5 (-1-2.2.0, p&lt;0.001, respectively. They also had higher NT-proBNP 325 (122-791) vs. 102 (48-342) pmol/l, p = 0.002. Using an adjusted Cox model, pre-HD ECW overhydration remained an independent factor associated with mortality (overhydration %: hazard ratio 1.15, 95% limits 1.03-1.28, p = 0.013), with a receiver operator curve (ROC) value of 0.7.
  
  
  CONCLUSIONS
  ECW excess is associated with increased mortality for HD patients, with ECW excess pre-dialysis being the strongest association, although these patients also had increased ECW post dialysis. Future trials are required to determine whether achieving euvolaemia as determined by bioimpedance improves patient survival.
authors: Faculty of Medicine, Mahasarakham University, Mahasarakham - Thailand.
authors: Kamonwan
authors: K
authors: Tangvoraphonkchai
authors: UCL Center for Nephrology, University College London Medical School, Royal Free Hospital, London - UK.
authors: Andrew
authors: A
authors: Davenport
mesh_terms: D000368:Aged; D001823:Body Composition / Q000502:physiology; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000401:mortality*; D014883:Water-Electrolyte Imbalance / Q000097:blood / Q000401:mortality*
chemical_list: D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain