A rapid review and narrative synthesis of the evidence for oral sodium chloride supplements in the management of heart failure.

Aims: Intravenous (i.v.) hypertonic saline alongside i.v. loop diuretics is sometimes used to enhance diuresis in people hospitalized with heart failure (HF) but is challenging to administer. Oral sodium chloride (NaCl) supplements might be a practical alternative, but little is known about their effects in patients with HF. We performed a rapid review of the relevant evidence. Methods and results: A rapid systematic review was registered (PROSPERO: CRD420250618965) and reported following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Medline and Cochrane Central Register of Controlled Trials databases were searched for studies involving adults with HF administered with oral NaCl. Randomized and observational studies were included. Studies of oral NaCl restriction or i.v. hypertonic NaCl were excluded. All available data were extracted. Risk of bias was evaluated using Risk of Bias 2 and Risk Of Bias In Nonrandomized Studies of Interventions tools. From an initial 335 records, five studies involving 139 patients were included. Oral NaCl did not affect weight or urine volume but were associated with higher serum and urinary sodium concentrations. Some studies reported that NaCl was associated with smaller diuretic-induced increases in serum urea and creatinine, lower haematocrit, higher plasma volume, and less neurohormonal activation compared to normal NaCl intake. Clinical outcomes, including hospital length of stay and mortality, were unaffected. The quality of evidence was limited by small sample sizes and methodological heterogeneity. Conclusion: For patients with HF treated with loop diuretics, higher oral NaCl intake may increase serum and urine sodium concentration, improve renal function, and reduce neurohormonal activation. There is insufficient evidence to support oral NaCl as an adjunct to diuretic treatment. More research is needed.