Early diuretic response and outcome prediction in ambulatory worsening heart failure: Natriuresis versus diuresis

Abstract

Aims

Early diuresis and natriuresis are commonly used to assess the efficacy of decongestive therapy following an acute heart failure episode. There is limited knowledge regarding which parameter better predicts adverse clinical outcomes, especially in the outpatient setting. This study investigated the prognostic value of both metrics in predicting 30-day adverse clinical events in an ambulatory worsening heart failure (WHF) scenario.

Methods and results

This is a post-hoc analysis of the SALT-HF trial involving 167 patients with ambulatory WHF randomized to receive intravenous furosemide with or without hypertonic saline solution. Early diuretic response was assessed through 3-h urine output and 3-h urinary sodium (uNa⁺) levels following intravenous (IV) diuretic infusion. We analysed their association with 30-day adverse events (defined as death, heart failure hospitalization, or the need for outpatient IV diuretics) using logistic regression analysis. Both exposures were examined along the continuum and dichotomized in their median. The discriminative ability between the exposures and endpoints was assessed by receiver operating characteristic curves (AUC-ROC).

Results

The median age of participants was 81 years, predominantly male (69.5%). Patients with lower 3-h urinary sodium and diuresis were older and exhibited reduced kidney function and haemoglobin levels. At 30 days, 50 (29.9%) of the sample experienced the composite endpoint. Multivariate analyses revealed that lower 3-h uNa⁺ was associated with a higher risk of 30-day adverse events (P = 0.008). Conversely, 3-h diuresis did not significantly predict 30-day adverse outcomes (P = 0.424). There was a trend towards a higher AUC-ROC for the inverse of 3-h natriuresis compared with 3-h diuresis: 0.680 versus 0.601, P = 0.092.

Conclusions

In patients with ambulatory WHF treated with IV furosemide, 3-h urinary sodium predicted 30-day outcomes whereas 3-h diuresis did not.