Early urinary sodium trajectory and risk of adverse outcomes in acute heart failure and renal dysfunction.

Abstract 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 24 hours (ΔUNa24 h) 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 ± 8.5 mL/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 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 ΔUNa24 h adds prognostic information over baseline values only when UNa+ at admission is ≤ 50 mmol/L.