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Abstract: PO1505

Reappraisal of Urinary Sodium Excretion as a Predictor of Clinical Outcomes in Heart Failure

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

  • 902 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

  • Bejjanki, Harini, University of Florida, Gainesville, Florida, United States
  • De Jesus, Eddy J., University of Florida, Gainesville, Florida, United States
  • Damarla, Vijay, Decatur Memorial Hospital, Decatur, Illinois, United States
  • Kazory, Amir, University of Florida, Gainesville, Florida, United States
Background

Congestion is established as the driver of adverse outcomes in heart failure (HF). Since removal of excess fluid and sodium is often the primary therapeutic objective in this setting, accurate monitoring of the progress of diuretic therapy is of critical importance. While weight change and fluid balance have conventionally been used for this purpose, inconsistent collection, inherent delay in data availability, and lack of distinction between water and sodium balance are among their limitations. We sought to explore the contemporary data on the use of urinary sodium (UNa) as a predictor of outcomes in these patients.

Methods

Articles cited in the PubMed database using keywords “heart failure” and “urine sodium” were searched. Available data from clinical trials published between June 2015 and May 2020 were included. The studies were selected if they prognosticated outcomes in the HF population through use of UNa. Pertinent data on clinical and laboratory parameters (e.g. dose and timing of diuretic therapy, eGFR, serum sodium, and UNa) were extracted and reviewed.

Results

A total of 14 studies with 2,350 participants were included, of which 11 were prospective. The study populations consisted of 12 acute HF cohorts, 1 chronic, and 1 with both. The mean age was 67 years (64% men) with an ejection fraction of 35% and an eGFR of 50 ml/min. Most studies (12 out of 14) used UNa concentration, 2 used fractional excretion and clearance of sodium. Surprisingly, while there was substantial variation across studies in the timing of the applied metric, those exploring clinical endpoints unanimously reported a correlation between low UNa excretion and various adverse outcomes (e.g. worsening renal function, HF readmission, and mortality).

Conclusion

Over the past few years, UNa has been the focus of much investigation as a tool for monitoring of therapy and prognostication in patients with HF. The findings of our study are two folds: 1) Regardless of the applied metric and its timing, contemporary data supports the use of UNa as a potent predictor of clinical outcomes in HF that lacks the limitations of conventional methods. 2) There is no consensus on the optimal cut off and time points for measurement of UNa in this setting. In order for UNa to be applied widely as a consistent and reliable tool, this knowledge gap needs to be addressed in future studies.