Renal profiling based on estimated glomerular filtration rate and spot urine sodium identifies high‐risk acute heart failure patients

Aims In acute heart failure (AHF), assessment of renal function comprises estimation of glomerular filtration rate (eGFR), which does not provide any information about renal sodium/water handling. We describe the interactions between urinary sodium concentration and eGFR to better characterize AHF patients. Methods and results In 219 patients with AHF, spot urine sodium (UNa + ) and eGFR were assessed on admission, day 1 and day 2 of hospitalization. We found no correlation between UNa + and eGFR (calculated on each consecutive day, as an average of all three values, and as changes from baseline; all P > 0.05). The population was subsequently divided into four profiles based on eGFR (preserved vs. impaired; cutoff of 60 mL/min/1.73 m 2 ) and UNa + (sodium excreter vs. non‐excreter; cutoff of 60 mmol/L). At day 1, there were 70 (31.9%) patients classified as preserved eGFR/sodium excreter, 37 (16.8%) as impaired eGFR/sodium non‐excreter, 72 (32.9%) as impaired eGFR/sodium excreter, and 40 (18%) as preserved eGFR/sodium non‐excreter. Both sodium non‐excreter profiles were associated with an increased risk of in‐hospital heart failure worsening [odds ratio (OR) 2.8, 95% confidence interval (CI) 1.3–6.4], inotrope use (OR 2.6, 95% CI 1.1–6.7) and rehospitalization due to AHF (OR 3.2, 95% CI 1.6–6.2; all P < 0.05). The preserved eGFR/sodium non‐excreter profile was associated with highest 1‐year mortality (52.5%) and remained an independent prognosticator after adjustment for other prognosticators (hazard ratio 2.9, 95% CI 1.7–5.2; P < 0.0005). Conclusions In AHF, values of spot UNa + and eGFR are not interrelated. Concomitant assessment of eGFR and spot UNa + may be useful for better clinical and therapeutic profiling of patients.