Clinical challenge of hyponatremia in heart failure

Association between hyponatremia, inflammation, and mortality in patients undergoing peritoneal dialysis: A nationwide observations

INTRODUCTION

Hyponatremia is the most common electrolyte disorder often present in peritoneal dialysis (PD) patients. The aim of this retrospective study was to investigate the effect of hyponatremia on mortality in patients undergoing PD.

METHODS

The health records of adult individuals with an inserted PD catheter identified via the centralized national e-health database were used.

RESULTS

The mean age of the 846 patients included in the study was 52.48 years (±14.6). The mean sodium level was 136.51 mEq/L. Sodium levels <137 mEq/L were associated with higher death risk independent of comorbidities. There was a 0.821 times less reduction in mortality for each mEq /L increase in serum sodium.

CONCLUSION

Our study provides evidence that monitoring and adjusting serum sodium levels is crucial in managing PD patients with hyponatremia, as low serum sodium level was found to be a significant and independent predictor of mortality.

Hypochloraemia is strongly and independently associated with mortality in patients with chronic heart failure

AIMS

Hyponatraemia is strongly associated with adverse outcomes in heart failure. However, accumulating evidence suggests that chloride may play an important role in renal salt sensing and regulation of neurohormonal and sodium-conserving pathways. Our objective was to determine the prognostic importance of hypochloraemia in patients with heart failure.

METHODS AND RESULTS

Patients in the BEST trial with baseline serum chloride values were evaluated (n = 2699). Hypochloraemia was defined as a serum chloride ≤96 mmol/L and hyponatraemia as serum sodium ≤135 mmol/L. Hypochloraemia was present in 13.0% and hyponatraemia in 13.7% of the population. Chloride and sodium were only modestly correlated (r = 0.53), resulting in only 48.7% of hypochloraemic patients having concurrent hyponatraemia. Both hyponatraemia and hypochloraemia identified a population with greater disease severity; however, renal function tended to be worse and loop diuretic doses higher with hypochloraemia. In univariate analysis, lower serum sodium or serum chloride as continuous parameters were each strongly associated with mortality (P < 0.001). However, when both parameters were included in the same model, serum chloride remained strongly associated with mortality [hazard ratio (HR) 1.3 per standard deviation decrease, 95% confidence interval (CI) 1.18-1.42, P < 0.001], whereas sodium was not (HR 0.97 per standard deviation decrease, 95% CI 0.89-1.06, P = 0.52).

CONCLUSION

Serum chloride is strongly and independently associated with worsened survival in patients with chronic heart failure and accounted for the majority of the risk otherwise attributable to hyponatraemia. Given the critical role of chloride in a number of regulatory pathways central to heart failure pathophysiology, additional research is warranted in this area.

Hyponatremia during hospitalization and in-hospital mortality in patients hospitalized from heart failure

Background

To date, the majority of studies on hyponatremia focussed on hyponatremia at admission, and came from developed countries. This study aimed to identify the prevalence of hyponatremia during hospitalization in patients hospitalized for HF and its association with in-hospital mortality.

Methods

This was an observational study using retrospective data from patients’ records between 2010–2013. It focused on those patients carrying an ICD-10 code of 150.0(Congestive Heart Failure) as their primary diagnosis.

Hyponatremia during hospitalization was defined as serum sodium level lower than 135 mEq/L obtained from a blood chemistry measurement on the next days after admission. Patients’ characteristics were examined and the association between hyponatremia during hospitalization and in-hospital mortality was analyzed.

Results

Among 464 patients hospitalized for HF, hyponatremia during hospitalization was observed in 22 % of patients with 44 % of this group had normal serum sodium level on admission.

Hyponatremia during hospitalization was associated with lower blood pressure on admission, both systolic and diastolic, peripheral oedema, ascites and fatigue. Patients having history of hospitalization for cardiac diseases and renal failure were higher in patients developing hyponatremia during hospitalization. In this group, amiodarone, heparin, insulin and antibiotics were administered more frequently. Factors potentially increase the risk of hyponatremia during hospitalization include history of fatigue (OR = 3.23, 95 % CI 1.79–5.82), presence of ascites (4.14, 1.84–9.31), and administration of heparin (3.85, 1.78–8.31) and antibiotics (3.08, 1.71–5.53). Length of hospital stay was significantly longer in patients with hyponatremia during hospitalization and in-hospital mortality was also higher compared to non-hyponatremic patients, 7.7 % and 29.1 %, respectively.

Conclusion

This study found that the prevalence of hyponatremia during hospitalization in patients hospitalized for HF was almost the same as hyponatremia on admission and administration of heparin and antibiotics can potentially worsen hyponatremia during hospitalization. In this study population, hyponatremia during hospitalization was found to be associated with in-hospital mortality.

Evaluation of lixivaptan in euvolemic and hypervolemic hyponatremia and heart failure treatment

INTRODUCTION

Lixivaptan is a selective vasopressin type 2 (V2) receptor antagonist that induces aquaresis, the electrolytes sparing excretion of water. Its ability to correct hyponatremia has been demonstrated in experimental animal studies as well as in clinical trials in humans. Recently, three Phase III, double-blind, randomized, placebo-controlled studies have been completed. In two studies, patients with euvolemic hyponatremia were enrolled, one in the inpatient and the other in the outpatient setting and the third study involved patients with hypervolemic hyponatremia hospitalized for decompensated heart failure (HF). The trials confirmed the efficacy of lixivaptan in raising serum sodium but raised concern about its safety in patients hospitalized with decompensated HF.

AREAS COVERED

The authors review original publications on lixivaptan and summarize their findings. Specifically, the authors present information regarding its structure, pharmacodynamics and kinetics, metabolism as well as its efficacy and safety in laboratory animals and human studies. Furthermore, the FDA website was accessed to obtain information presented at the September 13, 2012 meeting of the Cardiovascular and Renal Drugs Advisory Committee.

EXPERT OPINION

The published data indicate that lixivaptan raises sodium levels in hyponatremic patients and supports its use in patients with euvolemic hyponatremia. However, the authors note that more safety data are still needed specifically in patients with decompensated HF.