BACKGROUND: Hyponatremia is a prevalent electrolyte disorder in hospitalized patients indicative of greater morbidity and mortality. A large-scale retrospective analysis was conducted to evaluate the incremental burden of hospitalized hyponatremic (HN) versus non-HN patients in terms of hospital resource utilization, costs, and hospital readmissions in the real-world setting. METHODS: HN patients (=18 years) were selected from the Premier Hospital Database between January 1, 2007 and March 31, 2010 and matched to a non-HN control cohort using propensity score matching. Bivariate and multivariate statistics were employed to evaluate the differences in healthcare resource utilization, costs, and hospital readmissions between patient cohorts. RESULTS: Among the matched patient cohorts, length of stay (LOS) (8.8 +/- 10.3 vs 7.7 +/- 8.5 days, P < 0.001), hospital admission costs ($15,281 +/- $24,054 vs $13,439 +/- $22,198, P < 0.001), intensive care unit (ICU) LOS (5.5 +/- 7.9 vs 4.9 +/- 7.1 days, P < 0.001), and ICU costs ($8525 +/- $13,342 vs $7597 +/- $12,695, P < 0.001) were greater for the HN versus non-HN cohort, as were hospital readmission rates 30 days postdischarge. Multivariate regressions further demonstrated that hyponatremia was associated with an increase of 10.9% for LOS, 8.2% for total hospitalization costs, 10.2% for ICU LOS, and 8.9% for ICU costs. Additionally, after multivariate adjustment, hyponatremia was associated with a 15.0% increased chance for hospital readmission 30 days postdischarge (P < 0.0001). CONCLUSIONS: Hyponatremia is an independent predictor of increased hospitalization LOS and cost, ICU admission and cost, and 30-day hospital readmission, and therefore represents a potential target for intervention to reduce healthcare expenditures for a large population of hospitalized hyponatremic patients. Journal of Hospital Medicine 2012; (c) 2012 Society of Hospital Medicine
