Serial assessment of spot urine sodium predicts effectiveness of decongestion and outcome in patients with acute heart failure.

Abstract

The clinical significance of the measurement of urine sodium concentration (UNa+ ) in response to loop diuretic administration in patients with acute heart failure (AHF) is still unsettled. We studied the association of serial measurements of spot UNa+ during the first 48 h of AHF treatment with the indices of decongestion, renal function, and prognosis. We enrolled 111 AHF patients, all of whom received intravenous furosemide on admission. The mean spot UNa+ significantly increased in the 6 h sample (P< 0.05 vs. baseline) and returned to baseline values in the 24 and 48 h samples. Based on the increase or decrease/no change of UNa+ in the 6 and 48 h samples vs. baseline, patients were divided into two groups at each time point, respectively. Patients did not differ in baseline clinical and laboratory characteristics. Patients with a decrease/no change of UNa+ in the 6 and 48 h samples had a lower weight loss during hospitalization. Patients with a decrease/no change of UNa+ in the 48 h sample had a poorer diuretic response and a significant increase in the urinary levels of the tubular biomarkers: kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin. Low UNa+ and decrease/no change in UNa+ in the 6 and 48 h samples were independent predictors of higher risk of all-cause mortality during 1-year follow-up (all P< 0.05). In AHF, low spot UNa+ and lack to increase UNa+ in response to intravenous diuretics are associated with poor diuretic response, markers of tubular injury and high risk of 1-year mortality.