Lower urine sodium predicts longer length of stay in acute heart failure patients: Insights from the ROSE AHF trial.

Background In patients hospitalized with acute heart failure (AHF), low urine sodium concentration (U-Na) after diuretic treatment may identify patients at risk for longer length of stay (LOS) and adverse events. We investigated the prognostic significance of 24-hour cumulative postdiuretic urine sodium concentration in a multicenter clinical trial population. Methods The Renal Optimization Strategies Evaluation AHF (ROSE AHF) trial randomized 360 patients with AHF and renal dysfunction receiving intravenous diuretic to dopamine, nesiritide, or placebo. Sodium concentration was measured in cumulative urine sample collected during the first 24 hours after randomization in 298 patients. Based on prior studies, lower U-Na was defined as <= 60 mmol/L. Results Lower U-Na was present in 142 (48%) patients, who had longer LOS (7 days vs 5 days, P < .001) and less 72-hour weight loss (5.7 lb vs 9.0 lb, P < .001). These associations persisted after controlling for baseline estimated glomerular filtration rate and outpatient furosemide dose. Lower U-Na did not modify the null effects of dopamine or nesiritide on clinical outcomes. Results were similar for spot rather than cumulative 24-hour U-Na concentration. Conclusion In patients hospitalized for AHF and renal dysfunction, U-Na <= 60 mmol/L during the first 24 hours of diuresis identifies patients at risk for prolonged hospitalization but does not provide an indication for adjunctive dopamine or nesiritide.