title: Dialysate sodium concentration and the association with interdialytic weight gain, hospitalization, and mortality.
abstract: OBJECTIVE
  Recommendations to decrease the dialysate sodium (DNa) prescription demand analyses of patient outcomes. We analyzed morbidity and mortality at various levels of DNa, simultaneously accounting for interdialytic weight gain (IDWG) and for the mortality risk associated with lower predialysis serum sodium (SNa) levels.
  
  
  METHODS
  We used multiply-adjusted linear mixed models to evaluate the magnitude of IDWG and Cox proportional hazards models to assess hospitalizations and deaths in 29,593 patients from the Dialysis Outcomes and Practice Patterns Study with baseline DNa and SNa as predictors, categorized according to lowest to highest levels.
  
  
  RESULTS
  IDWG increased with higher DNa across all SNa categories, by 0.17% of body weight per 2 mEq/L higher DNa; however, higher DNa was not associated with higher mortality in a fully adjusted model (also adjusted for SNa; hazard ratio [HR]=0.98 per 2 mEq/L higher DNa, 95% confidence interval [CI] 0.95-1.02). Instead, higher DNa was associated with lower hospitalization risk (HR=0.97 per 2 mEq/L higher DNa, 95% CI 0.95-1.00, P=0.04). Additional adjustments for IDWG did not change these results. In sensitivity analyses restricted to study facilities, in which 90%-100% of patients have the same DNa (56%), the adjusted HR for mortality was 0.88 per 2 mEq/L higher DNa (95% CI 0.83-0.94). These analyses represented a pseudo-randomized experiment in which the association between DNa and mortality is unlikely to have been confounded by indication.
  
  
  CONCLUSIONS
  In the absence of randomized prospective studies, the benefit of reducing IDWG by decreasing DNa prescriptions should be carefully weighed against an increased risk for adverse outcomes.
authors: Arbor Research Collaborative for Health, 340 East Huron Street, Suite 300, Ann Arbor, MI 48104, USA.
authors: Manfred
authors: M
authors: Hecking
authors: Angelo
authors: A
authors: Karaboyas
authors: Rajiv
authors: R
authors: Saran
authors: Ananda
authors: A
authors: Sen
authors: Masaaki
authors: M
authors: Inaba
authors: Hugh
authors: H
authors: Rayner
authors: Walter H
authors: WH
authors: Hörl
authors: Ronald L
authors: RL
authors: Pisoni
authors: Bruce M
authors: BM
authors: Robinson
authors: Gere
authors: G
authors: Sunder-Plassmann
authors: Friedrich K
authors: FK
authors: Port
mesh_terms: D000368:Aged; D015314:Dialysis Solutions / Q000032:analysis*; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000009:adverse effects* / Q000401:mortality; D012964:Sodium / Q000097:blood*; D015430:Weight Gain
chemical_list: D015314:Dialysis Solutions; D012964:Sodium