title: Health care utilization, costs, and readmission rates associated with hyponatremia.
abstract: OBJECTIVE
  Hyponatremia is associated with higher morbidity and mortality rates among hospitalized patients. Our study evaluated health care utilization and associated costs of patients hospitalized with a primary diagnosis of hyponatremia.
  
  
  METHODS
  Hospitalized patients with a primary discharge diagnosis of hyponatremia (aged ≥ 18 years) were identified from the Premier Perspective™ database (January 1, 2007-March 31, 2010) and matched to non-hyponatremic (non-HN) patients using a combination of exact patient characteristic matching and propensity score matching. Univariate and multivariate statistics were used to compare hospital resource usage, costs, and 30-day readmission rates between cohorts.
  
  
  RESULTS
  Hospital length of stay (LOS) (± standard deviation) (3.78 ± 3.19 vs 3.54 ± 3.26 days; P < 0.001) and cost ($5396 ± $6500 vs $4979 ± $6152; P < 0.001 for the hyponatremic [HN] and non-HN patient cohorts, respectively) were greater for the HN cohort, but intensive care unit (ICU) costs ($3554 ± $6463 vs $3484 ± $8510; P = 0.828) and ICU LOS (2.37 ± 3.47 vs 2.52 ± 3.87; P = 0.345) did not differ between cohorts. The ICU admission rate (7.9% vs 4.4%; P < 0.001), as well as the 30-day readmission rate (12.1% vs 2.9%; P < 0.001) were greater for the HN cohort. After adjustment for key patient characteristics, hyponatremia was associated with a 7.6% increase in hospital LOS, an 8.9% increase in hospital costs, and a 9% increase in ICU costs. Hyponatremia was associated with an increased risk of ICU admission (odds ratio, 1.89, confidence limits, 1.72, 2.07; P < 0.001) and 30-day hospital readmission for hyponatremia (odds ratio, 4.76; confidence limits, 4.31, 5.26; P < 0.001).
  
  
  CONCLUSIONS
  Compared with non-HN patients, patients with a primary diagnosis of hyponatremia use a greater amount of hospital resources and represent a challenge to hospital profitability due to the increased likelihood of 30-day readmission.
authors: Ochsner Health System, New Orleans, LA, USA. sdeitelzweig@ochsner.org
authors: Steven
authors: S
authors: Deitelzweig
authors: Alpesh
authors: A
authors: Amin
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: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D006296:Health Services / Q000191:economics* / Q000706:statistics & numerical data; D017721:Hospital Costs / Q000706:statistics & numerical data* / Q000639:trends; D006801:Humans; D007010:Hyponatremia / Q000191:economics* / Q000401:mortality / Q000628:therapy; D007362:Intensive Care Units / Q000191:economics / Q000706:statistics & numerical data; D007902:Length of Stay / Q000191:economics / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge / Q000191:economics / Q000706:statistics & numerical data; D010359:Patient Readmission / Q000191:economics* / Q000706:statistics & numerical data; D057216:Propensity Score; D012189:Retrospective Studies; D055815:Young Adult