Can urine tests guide better diuretic dosing in heart failure?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion criteria: * At least 18 y/o and able to provide informed consent * Hospital admission (anticipated stay \>24 h after randomisation) with diagnosis of acute heart failure according to the treating physician * At least one of the following three signs of volume overload: 1. bilateral oedema 2+, indicating clear pitting 2. ascites that is amenable for drainage, confirmed by echography (no obligation to perform abdominal echocardiography, but necessary when presence of ascites is used as an entry criterion for the study) 3. uni- or bilateral pleural effusions that are amenable for drainage, confirmed by chest X-ray or lung ultrasound (no obligation to perform chest X-ray, but necessary when presence of pleural effusions is used as an entry criterion for the study) * Plasma NTproBNP level \>1,000 ng/L Exclusion criteria: * No possibility to collect reliable urine spot samples after diuretic administration * Administration of any diuretic within 6 h before randomisation, except for a mineralocorticoid receptor antagonist or sodium glucose co-transporter-2 inhibitor as part of the patient's maintenance treatment for heart failure. Patients can still be included after withholding these diuretics for 6 h, after which randomisation can be performed if they qualify all other criteria. * Severe kidney dysfunction, defined as an eGFR \<15 mL/min/1.73m² calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula and/or previous, current, or planned future renal replacement therapy * Systolic blood pressure \<90 mmHg, mean arterial pressure \<65 mmHg, or need for inotropes/vasopressor therapy at randomisation * Any acute coronary syndrome within 30 days prior to enrolment, defined as typical chest pain with a troponin rise above the 99th percentile of normal and/or electrocardiographic changes suggestive of cardiac ischemia * History of heart or kidney transplantation * History of mechanical circulatory support * Known obstructive hypertrophic cardiomyopathy, congenital heart disease, acute mechanical cause of acute heart failure (e.g., papillary muscular rupture), acute myocarditis, or constrictive pericarditis according to the treating physician * Pregnant or breastfeeding woman * Concomitant participation in another interventional study