The report is a product of the VA/HSR Evidence Synthesis Program.

In-Hospital Sodium Intake for Acute Decompensated Heart Failure

Takeaway: Adults hospitalized with acute decompensated heart failure consumed fewer calories on a restricted sodium diet compared to a higher sodium diet. Sodium restriction did not differentially affect other intermediate, clinical, or health service use outcomes. Supplemental sodium chloride with furosemide improved many intermediate, clinical, and health service use outcomes.

Acute Decompensated Heart Failure (ADHF) is a leading cause of hospitalization and rehospitalization in the U.S.. The treatment goal for people hospitalized with ADHF is to reverse acute hemodynamic abnormalities and improve heart failure symptoms. In addition to pharmacological therapies (e.g., diuretics and vasodilators), standard inpatient management of ADHF includes restricting dietary sodium. However, sodium restriction may negatively affect patients by activating the renin-angiotensin-aldosterone and antidiuretic systems, thereby worsening a primary driver of heart failure. There is also concern that patients find low-sodium food less flavorful, which could negatively affect nutrition intake and lead to poor adherence to a low-sodium diet.

Supplemental sodium chloride (NaCl)—given as either HSS (hypertonic saline solution) infusion or oral NaCl tablets—is proposed as an adjuvant therapy to loop diuretics in patients hospitalized with ADHF. HSS causes volume expansion and mobilization of fluid to the intravascular compartment, which improves kidney function, urine output, and weight loss. Despite the potential clinical benefits, providers may be hesitant to adopt supplemental sodium given concerns that increased sodium intake may exacerbate heart failure symptoms.

In response to a request from VHA’s Office of Hospital Medicine, HSR’s Evidence Synthesis Program (ESP) Center located in Providence, RI, conducted a systematic review on interventions affecting sodium intake for patients hospitalized for ADHF. Specifically, ESP investigators sought answers for the following questions:

• Among adults hospitalized for ADHF, what is the comparative effectiveness of different prescribed sodium intake interventions?
• Does effectiveness differ as a function of patient characteristics, including by age, comorbid conditions (e.g., hypertension, diabetes, stroke), existing vs new onset heart failure, preserved vs reduced ejection fraction or pre-hospitalization dietary sodium intake?

Investigators searched peer-reviewed articles in Medline (via PubMed), Embase, ClinicalTrials.gov, CINAHL, and the Cochrane Database of Systematic Reviews from inception to February 13, 2023. From nearly 10,000 potential articles, investigators accepted 20 studies for this review.

Summary of Findings

Investigators identified 5 studies (including 4 randomized-controlled studies or RCTs) that compared a low sodium diet to a higher sodium diet, and 15 studies (including 13 RCTs) that compared HSS with furosemide or, in one instance, oral NaCl with furosemide, to furosemide alone. The most frequently evaluated outcomes for dietary sodium interventions were weight loss, diuretic dose during hospitalization, and all-cause mortality. For sodium supplementation studies, weight was the most frequently reported outcome followed by urine output, serum sodium, serum creatinine, and length of hospital stay. Only one study was conducted in the United States and was not in the VA healthcare system. Key findings include the following:

• Adults hospitalized with ADHF consumed fewer calories on a restricted sodium diet compared to higher sodium diet. Sodium restriction did not differentially affect other intermediate, clinical, or health service use outcomes. Studies provided insufficient evidence for N-terminal pro-brain natriuretic protein (NT-proBNP), weight, and mortality. No study reported data on estimated glomerular filtration rate (eGFR) or serum cystatin C.
• Supplemental NaCl (mostly given as HSS) with furosemide significantly decreased serum creatinine, blood urea nitrogen (BUN), brain natriuretic peptide (BNP), and weight and increased eGFR, urine output, and serum sodium. There were no significant differences in NT-proBNP, serum aldosterone, plasma renin activity (PRA), or serum cystatin C.
• Supplemental NaCl improved some clinical outcomes (New York Heart Association functional class and thirst symptoms) and reduced hospital length-of-stay but did not affect intensive care unit admissions. The one study conducted in the United States found no significant difference in hospital length of stay between oral NaCl with furosemide and furosemide alone. No study reported data on clinical congestion score. Studies provided insufficient evidence on mortality and readmission outcomes.
• No study reported differences in effectiveness by patient characteristics (age, sex, or race/ethnicity), comorbid conditions, community dietary sodium intake, existing vs new onset heart failure, or preserved vs reduced ejection fraction. Finally, no study compared a dietary sodium restriction to sodium supplementation with furosemide.

Limitations

All dietary sodium RCTs were conducted in Brazil, and most HSS studies were conducted in Europe. The majority of European studies were conducted by three different author groups. Despite this, the overall clinical findings would likely translate to VA, since the underlying biology and mechanisms are not likely different by country. Health service use outcomes including reductions in hospital length of stay may be reproduced in VA patients, but the magnitude of change in length of stay (a measure particularly sensitive to a health system’s characteristics) may be substantially different than found in mostly European studies. In addition:

• Investigators were unable to compare effects by intervention dosing or duration.
• Outcomes of 30-day mortality and 30-day readmission may be affected by care after discharge, and the investigators did not evaluate corresponding outpatient care protocols.
• Investigators focused on studies conducted in an inpatient setting, where diet can be controlled by providers and patients are likely to be more compliant with treatment.

Future Research

The absence of adequately powered RCT data from North America presents an opportunity for VA to conduct its own effectiveness and implementation study of prescribed sodium strategies. Comparative effectiveness studies of different dosing strategies (durations and concentrations) are also needed to identify the optimal approach. The effect of sodium supplementation on length-of-stay in the United States also needs to be addressed.

Implications

Findings suggest that VA medical centers reconsider the routine practice of restricting sodium intake for patients admitted with ADHF. Sodium supplementation with loop diuretics to augment diuresis shows promise as a strategy to improve inpatient management of ADHF. In addition to evaluating the clinical data, VA decision-makers will need to consider implementation needs and barriers.

Providers and systems may be reluctant to change practice since the use of sodium in heart failure is counter-intuitive and discussed in medical curricula as something to be avoided. Sodium supplementation and intravenous diuretic protocols may require additional resources for patient monitoring and safety protocols. In addition, training medical staff will be critical to promote the safe use of HSS in selected patients with ADHF.

Mai HJ, Jutkowitz E, Kanaan G, et al. In-Hospital Sodium Intake for Acute Decompensated Heart Failure: A Systematic Review. Washington, DC: Evidence Synthesis Program, Health Services Research and Development Service, Office of Research and Development, Department of Veterans Affairs. VA ESP Project #22-116; 2023.

To view the full report, go to: vaww.hsrd.research.va.gov/publications/esp/hf-sodium-intake.cfm (Intranet only).

ESP is currently soliciting review topics from the broader VA community. Nominations will be accepted electronically using the online Topic Submission Form. If your topic is selected for a synthesis, you will be contacted by an ESP Center to refine the questions and determine a timeline for the report.

This Management e-Brief is provided to inform you about recent HSR&D findings that may be of interest. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs. If you have any questions or comments about this Brief, please email CIDER. The Center for Information Dissemination and Education Resources (CIDER) is a VA HSR&D Resource Center charged with disseminating important HSR&D findings and information to policy makers, managers, clinicians, and researchers working to improve the health and care of Veterans.

This report is a product of VA/HSR&D's Evidence Synthesis Program (ESP), which was established to provide timely and accurate synthesis of targeted healthcare topics of particular importance to VA managers and policymakers –; and to disseminate these reports throughout VA.

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