Validation of Natriuretic Response Prediction Equation in Patients with Acute Decompensated Heart Failure

Introduction The majority of acute decompensated heart failure (ADHF) admissions are driven by congestion. Sodium is the primary pathophysiologic driver of volume retention, with water passively following. However, monitoring sodium output in routine clinical practice is challenging. We previously created a model, the natriuretic response prediction equation (NRPE), to predict total sodium excretion following an IV dose of loop diuretic. The NRPE requires only a spot urine sodium and creatinine obtained 2 hours following diuretic administration (Figure 1). The objective of this study was to externally validate the NRPE. Hypothesis NRPE will accurately predict 6 hour post loop diuretic sodium output. Methods A total of 638 urine collections from 409 patients hospitalized with ADHF undergoing intravenous loop diuretic therapy were included. Intensively supervised urine collections were performed, and urine spot samples were taken at 2 hours after loop diuretic administration. A poor natriuretic response was defined as a sodium output of 150 mmol within this 6-hour period. Results The median IV furosemide equivalent dose was 80 mg (40-160), resulting in a cumulative 6-hour sodium output of 85 mmol (50-143) and urine output of 960 mL (640-1410). Poor natriuretic response was observed in 25% of the urine collections, averaging a cumulative sodium output of 29±13 mmol. Suboptimal and excellent responses were seen in 57% and 21% of the visits. The NRPE accurately predicted poor, suboptimal, and excellent natriuretic response, with an AUC of 0.92, 0.90, and 0.90, respectively (p Conclusions The NRPE, using only a 2 hour post diuretic spot urine sample, is a rapid and highly accurate method to monitor natriuretic response in ADHF patients.