PURPOSE: Hyponatremia is a common comorbidity among patients hospitalized with pneumonia. We hypothesized that the rate of correction of hyponatremia impacts the cost of hospitalization.
METHODS: We analyzed 980 hyponatremic (baseline Na<135 mEq/L) pneumonia patients hospitalized in 2003–2006 across 72 hospitals. Based on evaluation of hospital survival, we found a lower mortality for patients with a Na rate of rise in the first 24 hours of 1–7 mEq/L [favorable (1–7) 8.4% vs. unfavorable (<1 or >7) 14.5%, p<0.01]. We classified these patients in favorable Na management group. We conducted multivariable regression to estimate the effect of Na management on cost, controlling for admission severity, mortality status, and interaction of severity, mortality, and Na management status. Hospitalization cost was calculated by hospital and calendar year using the Center for Medicare and Medicaid Services (CMS) cost/charge ratios.
RESULTS: The overall in-hospital mortality was 11%. The prevalence of favorable Na management within 24 hours of hospitalization was 50% (n=490). Compared to unfavorable Na management group, patients with favorable Na management in the first 24 hours of hospitalization incurred lower hospital costs: median cost $8,516 (IQR: $5,165, $15,121) vs. $9,384 (IQR: $5,514, $17,635), p=.06. After adjusting for severity and other confounders, the estimated mean cost saving per patient associated with favorable Na management group was $2,939 (95% CI: $564, $5,314; p=0.02).
CONCLUSION: Fifty percent of admission hyponatremia is corrected at a favorable rate. The adjusted mean marginal cost saving associated with favorable hyponatremia management is over $2,900 per patient.
CLINICAL IMPLICATIONS: Further studies are needed to validate our finding of clinically and economically favorable rate of correction of admission hyponatremia among patients with pneumonia.
DISCLOSURE: Marya Zilberberg, No Financial Disclosure Information; No Product/Research Disclosure Information