title: Serum sodium levels and patient outcomes in an ambulatory clinic-based chronic kidney disease cohort.
abstract: BACKGROUND
  Chronic kidney disease (CKD) patients are prone to both hypo- and hypernatremia. Little has been published on the epidemiology of hypo- and hypernatremia in ambulatory patients with non-dialysis CKD.
  
  
  METHODS
  Data collected in two contemporaneous CKD cohort studies, the Renal Research Institute (RRI)-CKD study (n = 834) and the Study of Treatment of Renal Insufficiency: Data and Evaluation (STRIDE) (n = 1,348) were combined and analyzed to study the association between serum sodium (Na(+)) and clinical outcomes.
  
  
  RESULTS
  Baseline estimated glomerular filtration rate (eGFR) and Na(+) were 26 ± 11 ml/min/1.73 m(2) and 140.2 ± 3.4 mEq/l, respectively. The prevalence of Na(+) ≤135 mEq/l and ≥144 mEq/l was 6 and 16%, respectively. Higher baseline Na(+) was significantly associated with male sex, older age, systolic blood pressure, BMI, serum albumin, presence of heart failure, and lower eGFR. The risk of end-stage renal disease (ESRD) was marginally significantly higher among patients with Na(+) ≤135 mEq/l, compared with 140< Na(+) <144 mEq/l (referent), in time-dependent models (adjusted hazard ratio, HR = 1.52, p = 0.06). Mortality risk was significantly greater at 135< Na(+) ≤140 mEq/l (adjusted HR = 1.68, p = 0.02) and Na(+) ≥144 mEq/l (adjusted HR = 2.01, p = 0.01).
  
  
  CONCLUSIONS
  CKD patients with Na(+) ≤135 mEq/l were at a higher risk for progression to ESRD, whereas both lower and higher Na(+) levels were associated with a higher risk of mortality. While caring for CKD patients, greater attention to serum sodium levels by clinicians is warranted and could potentially help improve patient outcomes.
authors: Division of Nephrology, Department of Internal Medicine, Hanyang University Guri Hospital, Guri, Korea.
authors: Sang-Woong
authors: SW
authors: Han
authors: Anca
authors: A
authors: Tilea
authors: Brenda W
authors: BW
authors: Gillespie
authors: Fredric O
authors: FO
authors: Finkelstein
authors: Margaret A
authors: MA
authors: Kiser
authors: George
authors: G
authors: Eisele
authors: Peter
authors: P
authors: Kotanko
authors: Nathan
authors: N
authors: Levin
authors: Rajiv
authors: R
authors: Saran
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000554:Ambulatory Care Facilities; D001794:Blood Pressure; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000453:epidemiology; D006801:Humans; D006955:Hypernatremia / Q000097:blood / Q000453:epidemiology* / Q000401:mortality; D007010:Hyponatremia / Q000097:blood / Q000453:epidemiology* / Q000401:mortality; D007676:Kidney Failure, Chronic / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000401:mortality* / Q000503:physiopathology*; D012307:Risk Factors; D012737:Sex Factors; D012964:Sodium / Q000097:blood*
chemical_list: D012964:Sodium; D003404:Creatinine