de la Espriella R, et al. Rev Esp Cardiol (Engl Ed) 2020.
INTRODUCTION AND OBJECTIVES: Urinary sodium (UNa+) has emerged as a useful biomarker of poor clinical outcomes in acute heart failure (AHF). Here, we sought to evaluate: a) the usefulness of a single early determination of UNa+ for predicting adverse outcomes in patients with AHF and renal dysfunction, and b) whether the change in UNa+ at 24hours (ΔUNa24h) adds any additional prognostic information over baseline values.
METHODS: This is a post-hoc analysis of a multicenter, open-label, randomized clinical trial (IMPROVE-HF) (ClinicalTrials.gov NCT02643147) that randomized 160 patients with AHF and renal dysfunction on admission to a) the standard diuretic strategy, or b) a carbohydrate antigen 125-guided diuretic strategy. The primary end point was all-cause mortality and total all-cause readmissions.
RESULTS: The mean age was 78±8 years, and the mean glomerular filtration rate was 34.0±8.5mL/min/1.73 m2. The median UNa+ was 90 (65-111) mmol/L. At a median follow-up of 1.73 years [interquartile range, 0.48-2.35], 83 deaths (51.9%) were registered, as well as 263 all-cause readmissions in 110 patients. UNa+ was independently associated with mortality (HR, 0.75; 95%CI, 0.65-0.87; P <.001) and all-cause readmissions (HR, 0.92; 95%CI, 0.88-0.96; P <.001). The prognostic usefulness of the ΔUNa24h varied according to UNa+ at admission (P for interaction <.05). The ΔUNa24h was inversely associated with both end points only in the group with UNa+ ≤ 50 mmol/L. Conversely, no effect was found in the group with UNa+> 50 mmol/L.
CONCLUSIONS: In patients with AHF and renal dysfunction, a single early determination of UNa+ ≤ 50 mmol/L identifies patients with a higher risk of all-cause mortality and readmission. The ΔUNa24h adds prognostic information over baseline values only when UNa+ at admission is ≤ 50 mmol/L.