title: Hyponatremia as a predictor of mortality in peritoneal dialysis patients.
abstract: OBJECTIVE
  Hyponatremia is common in patients with chronic kidney disease and is associated with increased mortality in hemodialysis patients. However, few studies have addressed this issue in peritoneal dialysis (PD) patients.
  
  
  METHODS
  This prospective observational study included a total of 441 incident patients who started PD between January 2000 and December 2005. Using time-averaged serum sodium (TA-Na) levels, we aimed to investigate whether hyponatremia can predict mortality in these patients.
  
  
  RESULTS
  Among the baseline parameters, serum sodium level was positively associated with serum albumin (β = 0.145; p = 0.003) and residual renal function (RRF) (β = 0.130; p = 0.018) and inversely associated with PD ultrafiltration (β = -0.114; p = 0.024) in a multivariable linear regression analysis. During a median follow-up of 34.8 months, 149 deaths were recorded. All-cause death occurred in 81 (55.9%) patients in the lowest tertile compared to 37 (25.0%) and 31 (20.9%) patients in the middle and highest tertiles, respectively. After adjusting for multiple potentially confounding covariates, increased TA-Na level was associated with a significantly decreased risk of all-cause (HR per 1 mEq/L increase, 0.79; 95% CI, 0.73-0.86; p<0.001) and infection-related (HR per 1 mEq/L increase, 0.77; 95% CI, 0.70-0.85; p<0.001) deaths.
  
  
  CONCLUSIONS
  This study showed that hyponatremia is an independent predictor of mortality in PD patients. Nevertheless, whether correcting hyponatremia improves patient survival is unknown. Future interventional studies should address this question more appropriately.
authors.affiliation: Department of Internal Medicine, NHIS Medical Center, Ilsan Hospital, Goyangshi, Gyeonggi-do, Republic of Korea.
authors.forename: Tae Ik
authors.initials: TI
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Yung Ly
authors.initials: YL
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Hyungwoo
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Geun Woo
authors.initials: GW
authors.lastname: Ryu
authors.affiliation: Department of Internal Medicine, NHIS Medical Center, Ilsan Hospital, Goyangshi, Gyeonggi-do, Republic of Korea.
authors.forename: Ea Wha
authors.initials: EW
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Jung Tak
authors.initials: JT
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yoo
authors.affiliation: Department of Internal Medicine, NHIS Medical Center, Ilsan Hospital, Goyangshi, Gyeonggi-do, Republic of Korea.
authors.forename: Sug Kyun
authors.initials: SK
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea; Brain Korea 21 for Medical Science, Severance Biomedical Science Institute, Yonsei University, Seoul, Republic of Korea.
authors.forename: Shin-Wook
authors.initials: SW
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Kyu Hun
authors.initials: KH
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Dae Suk
authors.initials: DS
authors.lastname: Han
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Seung Hyeok
authors.initials: SH
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000009:adverse effects* / Q000401:mortality; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000175:diagnosis / Q000628:therapy