Luk A, et al. - Researchers investigated if the first spot urine sodium concentration (UNa) after diuretic initiation could select patients likely to require more intensive therapy during hospitalization for acute decompensated heart failure (ADHF). A composite of death at 90 days, mechanical circulatory support during admission, and requirement of inotropic support at discharge was the primary outcome. In patients with UNa≤ 60 the following were observed: lower admission blood pressure, less chronic neurohormonal antagonist prior to admission, and more than twice likelihood to experience the primary endpoint which was marginally significant after adjusting for renal function and baseline home loop diuretic. Overall, detection and triage of a population of HF patients at increased risk for adverse events and prolonged hospitalization may be facilitated by the evaluation of spot UNa after initial intravenous loop diuretic administration.