Abstract 4353: Economic Burden of Prolonged Hyponatremia in Patients Admitted with Congestive Hear Failure (CHF) and Hyponatremia
Introduction: Hyponatremia is a common electrolyte abnormality present in patients hospitalized with CHF.
Hypothesis: We sought to evaluate that the rate of correction of hyponatremia impacts the length of stay (LOS) and associated hospitalization cost.
Methods: We analyzed 9,427 hyponatremic (Na<135 mEq/L) CHF patients hospitalized in 2003–2006 across 72 hospitals. Based on evaluation of hospital survival, we found a lower mortality with a Na rate of rise in the first 48 hours of 1– 6 mEq/L (favorable group). We conducted multivariable regression to estimate the effect of Na management on LOS and cost, controlling for baseline Na, admission severity, mortality status, and interaction of severity and mortality. Hospitalization cost was calculated by hospital and calendar year using the Center for Medicare and Medicaid Services (CMS) cost/charge ratios.
Findings: The overall in-hospital mortality was 5.7%. The rate of favorable Na management within 48 hours of hospitalization was 60% (n=5,647). About 38% (n=3,557) patients had hyponatremia status unchanged or further deteriorated from baseline (prolonged hyponatremia). Another 2% (n=218) had Na corrected more than 7.0 mEq/L. After adjusting for confounders, the prolonged hyponatremia group showed 0.71 day increase in the LOS (95% CI: 0.45, 0.97 days; p<.0001) and $1,324 excess cost (95% CI: $569, $2,079; p<.001). The overcorrection group did not show significant difference in LOS and cost from the favorable Na group.
Conclusions: Only 60% CHF patients with admission hyponatremia are managed favorably in regards to the rate of serum Na correction. The adjusted mean marginal excess LOS of prolonged hyponatremia is about 1 day and the excess cost is over $1,300. Recognition and institution of measures to insure an appropriate and predictable rate of Na correction are needed in order to improve economic outcomes among hyponatremic patients with CHF.