Hyponatriemia as an independent cause of mortality

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 776-795-Cardiometabolic Risk & Vascular Biology
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-791
Igor Sturdik*, Monika Adamcova, Peter Jackuliak, Jana Kollerova, Tomas Koller and Juraj Payer
Medical Faculty of Comenius University, Bratislava, Slovakia
Background: Hyponatremia is the most common electrolyte abnormality with increased morbidity and mortality. It is defined as a change in the amount of sodium in the extracellular fluid below 135 mEq/L and its incidence among admitted patients is about 15-20%. The mortality rises up to 50% among patients with plasma sodium below 120 mEq/L. Hyponatremia can be mild (130 – 135 mEq/L), moderate (125 – 130 mEq/L) and severe (below 125 mEq/L).

Aim: The aim of our study was to assess the incidence and causes of hyponatremia among patients admitted to internal department, as well as to assess its impact on mortality.

Subjects and methods: A retrospective hospital record study was performed. A database search was conducted for all patients admitted to 5th Department of Internal Medicine, University Hospital in Bratislava from 1st January 2012 to 31st August 2012. All hyponatremic patients with plasma sodium levels below 135 mEq/L at admission day were considered as hyponatremic. A multivariete analysis of independent factors for mortality in hyponatriemia was performed using SPSS.

Results: 1.584 females and 1.090 males admitted to internal department were analyzed. Hyponatremia was found in 317 (11.8%, average age 69.39± 3.49 yrs) patients, of whom 177 were females and 140 were males. In 213 (67.2%) of admission reasons to hospital, the hyponatremia was not the primary diagnosis for admission; rather it was a manifestation of other underlying condition. The most common causes of hyponatremia included gastrointestinal losses (63 patients, 20%), decreased oral liquid and food intake (51 patients, 16%), clear water intake (48 patients, 15%), dilution reasons (44 patients, 14%), diuretics therapy (32 patients, 10%), and SIADH (10 patients, 3%). In as much as 67 patients (21%) the primary cause of hyponatremia was not identified, i.e. it was due to the combination of several causes. The mortality in patients with hyponatremia was 3-fold higher when compared to patients with normal plasma sodium levels (20.5% vs. 6.5, respectively), nevertheless, the mortality did not depend on the initial severity. Moreover a multivariate analysis revealed that abnormal mental status (as a manifestation of hyponatremia), dilution and decreased oral intake of fluids and food, and also serum urea above 7.73 mEq/L were independent factors associated with increased mortality.

Conclusion: Our study results confirmed that hyponatremia remains a common disorder across the spectrum of internal medicine department patients. Moreover several independent variables seem to have an effect on mortality. These results therefore emphasize a thorough approach based on clinical presentation, laboratory findings and the relative merits of various interventions to get the best outcome.

Nothing to Disclose: IS, MA, PJ, JK, TK, JP

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm