Spot Urine Sodium as Triage for Effective Diuretic Infusion in an Ambulatory Heart Failure Unit.

Background: Admission for diuresis remains a common and costly event in patients with advanced heart failure (HF). We tested whether spot urine sodium could identify patients likely to respond to ambulatory diuretic infusion without hospitalization.

Methods And Results: We prospectively followed 176 consecutive patients with advanced heart failure receiving intravenous furosemide for congestion in an ambulatory clinic. Spot urine sodium was measured in 1st voided urine after diuretic infusion and compared with 3-hour urine output and subsequent risk of 30-day hospitalization or emergency department (ED) visit. Spot urine sodium was significantly associated with urine output in a model adjusted for age, renal function, and blood urea nitrogen (P = .02). Higher urine sodium was associated with lower risk of hospitalization or ED visit within 30 days (odds ratio [OR] 0.82 [95% confidence interval 0.72-0.94] per 10 mmol/L increase; P < .001), in a model adjusted for hemoglobin (OR 0.80 [0.66-0.97]; P = .02) and systolic blood pressure (OR 0.82 [0.67-1.0]; P = .05). Spot urine sodium ≥65 mmol/L and urine output ≥1200 mL identified a lower-risk group for outpatient management.

Conclusion: High spot urine sodium after diuretic administration identifies HF patients likely to respond to an ambulatory diuretic infusion with lower rates of hospitalization or ED visits at 30 days.