title: Hyponatremia and long-term outcomes in chronic heart failure--an observational study from the Duke Databank for Cardiovascular Diseases.
abstract: BACKGROUND
  Hyponatremia is a well known predictor of short-term outcomes in heart failure (HF); however, its impact on long-term survival in HF patients with systolic dysfunction is not well established.
  
  
  RESULTS
  Using the Duke Databank for Cardiovascular Diseases, we identified 1,045 patients with HF and systolic dysfunction undergoing cardiac catheterization from January 2000 through December 2008. The effect of hyponatremia as independent predictor of all-cause death and cardiovascular death/rehospitalization was examined using a multivariable Cox proportional regression model. Hyponatremia was present in 107/1,045 patients (10.2%). Hyponatremic patients were older, more likely to be anemic, with higher heart rate and levels of blood urea nitrogen, lower blood pressure, and more severe HF. Using an unadjusted analysis, hyponatremia was associated with higher risk of all-cause death (hazard ratio [HR] 1.89, 95% confidence interval [CI] 1.44-2.49; P < .0001) and of cardiovascular death/rehospitalization (HR 1.40, 95% CI 1.11-1.77; P = .005) at 4.5 years. When entered into a multivariable Cox model, hyponatremia remained significant for all-cause death (HR 1.42, 95% CI 1.07-1.88) and for cardiovascular death/rehospitalization (HR 1.45, 95% CI 1.14-1.86).
  
  
  CONCLUSIONS
  Hyponatremia is relatively common in HF patients with LV dysfunction and is independently associated with increased risk of all-cause mortality and cardiovascular mortality/rehospitalization.
authors.affiliation: Section of Cardiovascular Diseases, Department of Experimental and Applied Medicine, University of Brescia, Brescia, Italy. luca_bettari@yahoo.it
authors.forename: Luca
authors.initials: L
authors.lastname: Bettari
authors.forename: Mona
authors.initials: M
authors.lastname: Fiuzat
authors.forename: Linda K
authors.initials: LK
authors.lastname: Shaw
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Wojdyla
authors.forename: Marco
authors.initials: M
authors.lastname: Metra
authors.forename: G Michael
authors.initials: GM
authors.lastname: Felker
authors.forename: Christopher M
authors.initials: CM
authors.lastname: O'Connor
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization; D002908:Chronic Disease; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D006760:Hospitalization; D006801:Humans; D007010:Hyponatremia / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009657:North Carolina; D016016:Proportional Hazards Models; D012720:Severity of Illness Index; D016019:Survival Analysis; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology