Spot Analysis of Natriuresis to Guide up- or Down-titration of Diuretic Therapy in Ambulatory Patients With Chronic Heart Failure

Spot Analysis of Natriuresis to Guide up- or Down-titration of Diuretic Therapy in Ambulatory Patients With Chronic Heart Failure (SAND-HF)

Heart failure is a chronic condition that causes congestion and frequent hospitalizations. Diuretic doses are usually adjusted based on clinical judgment without an objective measure of response. This study will test the feasibility of using point-of-care urine sodium measurements to guide up-titration or down-titration of loop diuretics in ambulatory patients with heart failure.

Participants will be assigned to one of three groups based on congestion status. Groups 1 and 2 will be randomized 1:1 to natriuresis-guided therapy or standard care. Group 3 will be observational. The 90-day pilot trial will evaluate feasibility, clinical outcomes, and usability of a urine sodium-guided titration strategy.

Heart failure is commonly associated with sodium retention and congestion. Loop diuretics are used to relieve congestion but are typically adjusted based on symptoms and clinical judgment. Spot urine sodium concentration is an objective measure of diuretic response that may help personalize treatment. A point-of-care urine sodium sensor provides rapid results and may support effective decongestion or safe reduction of diuretics when appropriate.

This prospective, two-center pilot study includes three clinical groups:

Group 1: Up-titration cohort Patients with clinical congestion or objective evidence of congestion. These participants will be randomized 1:1 to natriuresis-guided up-titration or standard care.

Group 2: Down-titration cohort Stable, euvolemic patients who may safely reduce diuretic therapy. These participants will be randomized 1:1 to natriuresis-guided down-titration or standard care.

Group 3: Observational cohort The first 100 screened patients who do not meet criteria for Groups 1 or 2. These participants will undergo baseline assessments and routine follow-up without intervention.

Urine sodium will be measured at baseline and follow-up visits. Randomized participants will have diuretic doses adjusted based on predefined algorithms. Standard care participants will receive usual clinical management.

The primary aim is to assess feasibility, including recruitment, retention, adherence to sampling procedures, and workflow implementation. Secondary analyses will describe clinical, laboratory, and symptom-based outcomes to inform development of a larger definitive trial.

Inclusion Criteria:

• Age ≥18 years
• Diagnosis of heart failure according to the Universal Definition
• Use of loop diuretics
• Residing in VCH or PHC regions

Group-specific inclusion:

Group 1: Congestion score ≥5 OR objective congestion; stable furosemide ≥1 week Group 2: NYHA I-II; congestion score <5; no recent HF hospitalization; stable furosemide ≥1 month Group 3: First 100 eligible patients not meeting criteria for Groups 1 or 2

Exclusion Criteria:

• eGFR <20 mL/min/1.73m²
• Renal replacement therapy
• High-risk clinical status requiring hospitalization
• Inability to consent or perform required urine sampling