Economic impact of hyponatremia in hospitalized patients with cancer

Abstract

17053 Background: Hyponatremia, defined as a serum sodium concentration ([Na+]) =134 mEq/L, is a common electrolyte abnormality in hospitalized cancer patients that may be caused by the primary tumor or metastasis, diagnostic or therapeutic interventions, or a secondary complication. Hospital-acquired hyponatremia is associated with higher costs of care, but many patients present with hyponatremia at admission. Methods: This retrospective case-controlled study assessed the outcomes and cost of care among patients hospitalized for neoplasm who presented with hyponatremia at admission. Laboratory and cost-accounting data from 841 adult patients admitted to an 811-bed university hospital between January 2004 and May 2005 with a principal diagnosis of neoplasm and either mild-to- moderate or moderate-to-severe hyponatremia (serum [Na+] 130–134 mEq/L or <130 mEq/L, respectively) were compared with data from control subjects with matching ICD-9 codes and normal serum [Na+] (135–145 mEq/L) at admission during the same period. Endpoints included hospital length of stay (LOS), ICU admissions, in-hospital mortality, and total costs per admission. Results: Hyponatremia was evident in 18.9% of patients admitted for neoplasm. Patients with moderate-to-severe hyponatremia (n=192) and mild-to- moderate hyponatremia (n=649) demonstrated a significantly longer hospital LOS, higher ICU admission rate, higher in-hospital mortality, and higher median costs than control subjects (n=3610) (Table). These differences among groups remained significant after adjustments were made for age, race, sex, and comorbidity score. Conclusions: Cancer patients presenting with hyponatremia at admission have a longer hospital LOS and higher risk of death and cost of care than do cancer patients presenting without hyponatremia. [Table: see text] No significant financial relationships to disclose.