title: Baseline hyponatremia does not predict two-year mortality in patients with chronic peritoneal dialysis.
abstract: OBJECTIVE
  Hyponatremia is a common electrolyte abnormality in a variety of medical conditions. Lower predialysis serum sodium concentration is associated with an increased risk of death in oligoanuric patients on hemodialysis. However, whether hyponatremia affects the short-term mortality in chronic peritoneal dialysis (CPD) patients remains unclear.
  
  
  METHODS
  We conducted a cross-sectional and two-year follow-up review retrospectively, and 318 patients with CPD were enrolled in a medical center. Serum sodium levels were measured at baseline and categorized as quartile of Na: quartile 1 (124-135 mEq/L), quartile 2 (136-139), quartile 3 (140-141) and quartile 4 (142-148). Mortality and cause of death were recorded for longitudinal analyses.
  
  
  RESULTS
  The patients with higher quartile (higher serum sodium) had a trend of lower age, peritoneal dialysis (PD) duration, co-morbidity index, D/P Cr and white blood cell counts and higher renal Kt/Vurea (Kt/V) and serum albumin level. Stepwise multiple linear regression analysis showed that serum sodium level was positively associated with albumin, residual renal Kt/V and negatively associated with age and PD duration in CPD patients. After two-year follow-up, stepwise multivariate Cox proportional hazards model demonstrated that age, co-morbidity index and serum albumin were the significant risk factors for all-cause two-year mortality, but not serum sodium levels.
  
  
  CONCLUSIONS
  Serum sodium level in CPD patients is associated with nutritional status, residual renal function and duration of PD. However, baseline serum sodium level is not an independent predictor of two-year mortality in CPD patients.
authors.affiliation: Kidney Research Center, School of Medicine, Chang Gung Memorial Hospital, Chang Gung University , Taoyuan, Taiwan , ROC.
authors.forename: Kuan-Hsing
authors.initials: KH
authors.lastname: Chen
authors.forename: Chao-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Cheng-Chia
authors.initials: CC
authors.lastname: Lee
authors.forename: Chu-Man
authors.initials: CM
authors.lastname: Weng
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Hung
mesh_terms: D000328:Adult; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000401:mortality*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000401:mortality*; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012964:Sodium / Q000097:blood; D015996:Survival Rate; D013624:Taiwan
chemical_list: D012964:Sodium
keywords: Hyponatremia; mortality; peritoneal dialysis; serum sodium