title: Predialysis hypernatremia is a prognostic marker in acute kidney injury in need of renal replacement therapy.
abstract: OBJECTIVE
  The present study aimed to evaluate the prognostic impact of predialysis dysnatremia in patients with acute kidney injury requiring renal replacement therapy (RRT).
  
  
  METHODS
  A secondary analysis of a prospective multicenter cohort study was performed. Serum sodium (Na) concentrations were categorized immediately before the first RRT as normonatremia (135≤Na ≤145mEq/L), hyponatremia (mild [130≤Na ≤134mEq/L] or severe [Na ≤129mEq/L]), and hypernatremia (mild [146≤Na ≤155mEq/L] or severe [Na ≥156mEq/L]). Multivariable logistic regression was used to estimate the impact of sodium levels categories on hospital mortality.
  
  
  RESULTS
  Dysnatremia occurred in 47.3% of 772 included patients. Hypernatremia was more frequent than hyponatremia (33.7% vs 13.6%, P=.001). Intensive care unit (ICU) and hospital mortality rates were 64.6% and 69%, respectively. Hospital mortality was higher in severe hypernatremia (89.1% [95% confidence interval {CI}, 78.7%-95.8%] vs 64.6% [CI, 59.8%-69.2%], P<.001, in normonatremia). Older patients, clinical admission, number of comorbidities, length of ICU stay before the beginning of RRT, and the number of organ dysfunctions were associated with higher hospital mortality. In multivariate analysis, severe hypernatremia (odds ratio, 2.87; 95% CI, 1.2-6.9), poor chronic heath status, severity of illness, sepsis, and lactate were independently associated with outcome.
  
  
  CONCLUSIONS
  Almost 50% of patients with acute kidney injury in need of RRT in the ICU had mild or severe dysnatremia before dialysis initiation. Hypernatremia was the main sodium disturbance and independently associated with poor outcome in the study population.
authors.affiliation: Nephrology Department, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil; NepHro consultoria, Rio de Janeiro, Brazil; Rede D' Or de Hospitais, Rio de Janeiro, Brazil.
authors.forename: Renata S
authors.initials: RS
authors.lastname: Mendes
authors.affiliation: D'Or Institute for Research and Education, Rio de Janeiro, Brazil.
authors.forename: Márcio
authors.initials: M
authors.lastname: Soares
authors.affiliation: NepHro consultoria, Rio de Janeiro, Brazil; Rede D' Or de Hospitais, Rio de Janeiro, Brazil.
authors.forename: Carla
authors.initials: C
authors.lastname: Valente
authors.affiliation: Nephrology Department, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: José Hermógenes
authors.initials: JH
authors.lastname: Suassuna
authors.affiliation: NepHro consultoria, Rio de Janeiro, Brazil; Rede D' Or de Hospitais, Rio de Janeiro, Brazil; Nephrology Department, Hospital Universitário Clementino Franga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Rocha
authors.affiliation: Nephrology Department, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil; NepHro consultoria, Rio de Janeiro, Brazil; Rede D' Or de Hospitais, Rio de Janeiro, Brazil. Electronic address: emaccariello@yahoo.com.br.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Maccariello
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000150:complications / Q000401:mortality / Q000628:therapy; D000368:Aged; D015897:Comorbidity; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D006955:Hypernatremia / Q000097:blood* / Q000401:mortality / Q000503:physiopathology; D007362:Intensive Care Units; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies; D006435:Renal Dialysis; D017582:Renal Replacement Therapy / Q000379:methods*; D012720:Severity of Illness Index; D012964:Sodium / Q000097:blood*
chemical_list: D012964:Sodium
keywords: Acute kidney injury; Dysnatremia; ICU; Outcomes; Renal replacement therapy