title: Healthcare resource burden associated with hyponatremia among patients hospitalized for heart failure in the US.
abstract: OBJECTIVE
  To evaluate the burden of hyponatremia in terms of hospital resource utilization, costs, and 30-day hospital readmission among patients hospitalized for heart failure (HF) in routine clinical practice.
  
  
  METHODS
  Hyponatremic (HN) patients (≥18 years of age) with HF discharged between January 2, 2007 and March 31, 2010 were selected from the Premier Hospital Database and matched to non-HN HF patients using exact and propensity score matching. Univariate and multivariate statistics were utilized to compare hospital resource utilization (total and intensive care unit (ICU)) and associated costs and 30-day hospital readmission among cohorts.
  
  
  RESULTS
  The study population included 51,710 subjects (HN = 25,855, non-HN = 25,855). In comparison to the non-HN cohort, length of stay (LOS) (7.7 ± 8.3 vs 6.3 ± 7.6 days, p < 0.001), hospitalization cost ($13,339 ± $19,273 vs $10,475 ± 15,157, p < 0.001), ICU LOS (4.9 ± 5.4 vs 4.2 ± 5.4 days, p < 0.001) and ICU cost ($7195 ± $9522 vs $5618 ± 10,919, p < 0.001) as well as rate of 30-day readmission (all cause: 25.3% vs 22.2%, p < 0.001; hyponatremia-related: 21.4% vs 5.0%, p < 0.001) were greater for the HN cohort. After adjustment, hyponatremia was associated with a 21.5% increase in hospital LOS, a 25.6% increase in hospital cost, a 13.7% increase in ICU LOS and a 24.6% increase in ICU cost. Additionally, hyponatremia was associated with increased risk of ICU admission (Odds Ratio (OR) = 1.58, [CI = 1.37, 1.84], p < 0.001) and 30-day hospital readmission (all cause: OR = 1.19, [CI = 1.14, 1.24], p < 0.001; hyponatremia-related: 5.10 [CI = 4.77, 5.46], p < 0.001).
  
  
  CONCLUSIONS
  Laboratory data for serum sodium level are not available in the Premier database and the severity of hyponatremia could not be established, although several patient variables were controlled for in this study by exact and propensity score matching techniques.
  
  
  CONCLUSIONS
  Hyponatremia in HF patients is a predictor of increased hospital resource use and represents a potential target for intervention to reduce healthcare expenditures.
authors: Department of Medicine, University of California, Irvine, Irvine, CA 92868, USA. anamin@hs.uci.edu
authors: Alpesh
authors: A
authors: Amin
authors: Steven
authors: S
authors: Deitelzweig
authors: Rudell
authors: R
authors: Christian
authors: Keith
authors: K
authors: Friend
authors: Jay
authors: J
authors: Lin
authors: Timothy J
authors: TJ
authors: Lowe
mesh_terms: D000368:Aged; D017281:Cost of Illness; D005260:Female; D006295:Health Resources / Q000706:statistics & numerical data*; D006333:Heart Failure / Q000191:economics*; D006760:Hospitalization / Q000191:economics*; D006801:Humans; D007010:Hyponatremia / Q000191:economics*; D008297:Male; D009657:North Carolina; D010359:Patient Readmission; D012189:Retrospective Studies; D014481:United States