title: Hyponatremia and long-term mortality in survivors of acute ST-elevation myocardial infarction.
abstract: BACKGROUND
  Hyponatremia, a marker of neurohormonal activation, is a common electrolyte disorder among patients with acute ST-elevation myocardial infarction. The long-term prognostic value of hyponatremia during the acute phase of infarction is not known.
  
  
  METHODS
  We studied 978 patients with acute ST-elevation myocardial infarction and without a history of heart failure who survived the index event. During the hospital stay, sodium levels were obtained on admission and at 24, 48, and 72 hours. The median duration of follow-up after hospital discharge was 31 months (range, 9-61 months).
  
  
  RESULTS
  Hyponatremia, defined as a mean serum sodium level less than 136 mEq/L, was present during admission in 108 patients (11.0%). In a multivariable Cox proportional hazards model adjusting for other potential clinical predictors of mortality and for left ventricular ejection fraction, hyponatremia during admission remained an independent predictor of postdischarge death (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.3-3.2; P = .002). Hyponatremia during admission was also independently associated with postdischarge readmission for heart failure (HR, 1.6; 95% CI, 1.1-2.6; P = .04). When serum sodium level was used as a continuous variable, the adjusted HR for death or heart failure was 1.12 for every 1-mEq/L decrease (95% CI, 1.07-1.18; P<.001).
  
  
  CONCLUSIONS
  Hyponatremia in the early phase of ST-elevation myocardial infarction is a predictor of long-term mortality and admission for heart failure after hospital discharge, independent of other clinical predictors of adverse outcome and left ventricular ejection fraction.
authors.affiliation: Department of Cardiology, Rambam Medical Center and Rappaport Medical School, Haifa, Israel.
authors.forename: Alexander
authors.initials: A
authors.lastname: Goldberg
authors.forename: Haim
authors.initials: H
authors.lastname: Hammerman
authors.forename: Sirouch
authors.initials: S
authors.lastname: Petcherski
authors.forename: Mithal
authors.initials: M
authors.lastname: Nassar
authors.forename: Alexander
authors.initials: A
authors.lastname: Zdorovyak
authors.forename: Sergey
authors.initials: S
authors.lastname: Yalonetsky
authors.forename: Michael
authors.initials: M
authors.lastname: Kapeliovich
authors.forename: Yoram
authors.initials: Y
authors.lastname: Agmon
authors.forename: Rafael
authors.initials: R
authors.lastname: Beyar
authors.forename: Walter
authors.initials: W
authors.lastname: Markiewicz
authors.forename: Doron
authors.initials: D
authors.lastname: Aronson
mesh_terms: D000368:Aged; D005260:Female; D006333:Heart Failure / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D007010:Hyponatremia / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000401:mortality / Q000503:physiopathology; D011379:Prognosis; D016016:Proportional Hazards Models; D013318:Stroke Volume; D017741:Survivors