Sodium abnormalities

Review article: NEJM 2015;372:55-65.

Disorders of Plasma Sodium - Causes, Consequences, and Correction.

Sterns RH.

Abstract

This review considers the causes and consequences of an abnormal plasma sodium concentration and offers a framework for correcting it.

PMID:

 

25551526

 

[PubMed - as supplied by publisher]

General Cardiology: Heart Failure, Hyponatremia, Mortality

CIRCHEARTFAILURE.111.961011Published online before print June 14, 2011,

Impact of Change in Serum Sodium Concentration on Mortality in Patients Hospitalized with Heart Failure and Hyponatremia

1. Vinay D. Madan,
2. Eric Novak and
3. Michael W. Rich*

Abstract

Background—Hyponatremia is a common electrolyte abnormality among patients hospitalized with heart failure and it is a marker for increased short-term and long-term mortality. However, little is known about the time-course of hyponatremia and whether changes in serum sodium levels impact clinical outcomes.

Methods and Results—322 patients hospitalized with decompensated heart failure and serum sodium <135 mmol/L were evaluated. Following hospital discharge, the first sodium value obtained within a 60-270 day period was recorded, and patients were classified into 3 groups based on whether the serum sodium value increased (≥2 mmol/L), decreased (≤2 mmol/L), or remained unchanged (±1 mmol/L) relative to the baseline value. Kaplan-Meier survival curves were constructed to illustrate mortality as a function of change in sodium concentration over time, and a Cox-proportional hazards model was constructed to determine if change in serum sodium concentration predicted mortality after adjusting for relevant covariates. The mean age of the population was 66 years, 45% were women, and 55% were Caucasian. The mean baseline sodium level was 131 mmol/L and the mean ejection fraction was 32.5%. 222 patients (68.9%) exhibited an increase in sodium during follow-up; in 57 patients (17.7%) the level was unchanged and in 43 patients (13.4%) there was a decrease in sodium level. During a median follow-up of 610 days, there was a strong positive association between change in sodium level and survival (p for trend <0.001); i.e., increased sodium was associated with decreased mortality. In multivariable analysis, change in sodium concentration and higher blood urea nitrogen were the strongest predictors of mortality (both p<0.0001).

Conclusions—Among patients hospitalized with heart failure and hyponatremia, change in serum sodium concentration over time is a strong predictor of long-term survival.