Urinary sodium to guide diuretic therapy in acute heart failure: results of a national survey

BACKGROUND AND AIMS: Urinary sodium (uNa+) is a promising tool to guide diuretic therapy in acute heart failure (AHF), yet its real-world adoption is uncertain. We aimed to evaluate current practices, perceived utility, and barriers to uNa⁺-guided management among physicians managing AHF in Spain. METHODS: We conducted a nationwide cross-sectional electronic survey in June 2025 of clinicians from cardiology, internal medicine, emergency medicine, and nephrology. The questionnaire assessed the frequency and timing of uNa+ monitoring in inpatient and outpatient settings, thresholds for poor response, therapeutic adjustments, and perceived benefits and barriers. RESULTS: A total of 413 physicians responded: 138 (33%) from cardiology, 159 (39%) from internal medicine, 78 (19%) from emergency medicine, and 38 (9%) from nephrology. Overall, 70% reported measuring uNa+ during AHF hospitalization, but only 18% did so routinely. Outpatient application remained infrequent (32%). Nephrologists showed the highest usage in both inpatient (90%) and outpatient (61%) settings. The most frequent cut-off to define diuretic resistance was <50 mmol/l. Therapeutic strategies differed by specialty: loop diuretic escalation was more frequent in cardiology and emergency medicine, while thiazides were preferred in internal medicine and nephrology. Most participants (78%) considered uNa⁺ monitoring clinically useful. Major barriers included lack of standardized protocols, limited training, therapeutic inertia, and logistical constraints. CONCLUSIONS: While uNa⁺ monitoring is valued by clinicians, its use in AHF in Spain remains inconsistent across specialties. Addressing implementation barriers through education, protocols, and decision-support tools is critical to a broader adoption of uNa⁺ guided therapy in routine care.