Introduction: Hyponatremia is the most frequent electrolyte disorder found in clinical practice, and has been associated with increased morbimortalty. Hyponatremia is even more common among patients receiving parenteral nutricion(PN), a therapy increasingly in use. However, the morbimortality of hyponatremic patients on PN is unknown.
Methods: Retrospective study, selecting all patients receiving PN in a teaching hospital from 01/11/11 to 01/06/12. We evaluated hospital length-of-stay (LOS), in-hospital mortality, serum Sodium (SNa) at admittance, at start and end of PN, and at discharge. Hyponatremia defined as glycemia- corrected SNa < 135 mmol/L, triglycerides<400 mg/dl. X2, T-test, Mann.whitney U, Logistic regression. SPSS 15.
Results: Two hundred and twenty-two patients received PN (57.2% males). Median age 75. 14.5% presented malnutrition (by BMI). Charlson index 3.3 (SD2.4). LOS: 30[20-40] days. Mortality: 17.7%. 50.4% (112/222) presented hyponatremia in at least one SNa determination, 27% in at least 25% of SNas, 15.7% in at least 50% of SNas, and 3% in at least 75% of SNas. 23.2% of hyponatremic NP patients died during hospitalization, as compared with 11.8% of normonatremics. However, only sustained hyponatremia (with 75% or more SNa determinations <135 mmol/L) was independently associated with increased mortality, following correction for age, gender, Charlson index, and BMI (OR 7.38 [IC 95%: 1.0750.8]; P=0.042). LOS <30 days were found in 42.8% of PN patients with hyponatremia versus 72.7% with normonatremia. (P=0.001).Logistic regression analysis indicated that the absence of hyponatremia was associated with a shorter LOS (< 30 days), even when adjusted for comorbilities (OR:3.89; CI: 95%: 2.117.18; P=0.001).
Conclusions: The presence of sustained hyponatremia is independently associated with increased mortality in patients receiving parenteral nutrition. The absence of hyponatremia is independently associated with a shorter hospital length-of-stay. Hyponatremia should not be overlooked in PN patients.