To salt or not to salt in heart failure, that is the question!
Carpaij, N., Dijkhorst-Oei, L.T.
Locatie(s): Auditorium 1
Categorie(ën): Plenaire sessie; Presentations "Schop de Heilige Huisjes omver!"
Moderator:
Mw. dr. H.A.H. Kaasjager, Arnhem
Panelleden
Mw. dr. P.C. Oldenburg, Amersfoort
Mw. W.E.M. Schouten, Amsterdam
Dr. F.L.J. Visseren, Utrecht
Introduction: Current guidelines and patient folders advise sodium restriction to < 2 gr/day in patients with moderate to severe chronic heart failure (HF). The relationship of salt intake to blood pressure (BP) is the basis for the belief that restriction in dietary sodium intake will prevent BP-related cardiovascular events. In chronic HF, reducing BP and extracellular volume through salt restriction is thought to prevent the detrimental rise in pre-and afterload. Pharmacological treatment is supported by a wealth of evidence. However, guidelines report little evidence for the aforementioned life-style intervention with large impact on quality of life.
Clinical question: What is the evidence for a low-sodium diet with respect to better outcome in chronic HF patients?
Literature search: A literature search was conducted using the PubMed database. The entered search terms were: ‘low sodium diet’, ‘systolic heart failure patients’ AND ‘mortality’. Fifteen articles were found of which two were eligible.
Results: A systematic review and meta-analysis written by DiNicolantonio et al. evaluated six randomized trials comparing low-sodium diet (1.8 gr/day; 80 mmol/day) with normal-sodium diet (2.8 gr/day; 120 mmol/day) in 2774 patients with HF with reduced ejection fraction (HFrEF). Compared with a normal diet, a low-sodium diet increased all cause mortality (RR 1.95; 95% CI 1.66-2.29), sudden death (RR 1.72; 95% CI 1.21-2.44), death due to HF (RR 2.23; 95% CI 1.77-2.81) and HF readmissions (RR 2.10; 95% CI 1.67-2.64). One prospective study by Arcand et al. evaluated 123 stable ambulatory patients with systolic HF during a median follow-up time of 3 years. Mean sodium intakes were 1.4 ± 0.3; 2.4 ± 0.3 and 3.8 ± 0.8 gr/day in the lower, middle and upper tertiles, respectively. The high-sodium tertile was associated with an adjusted hazard ratio of 1.39 (95% CI 1.06-1.83) for all-cause hospitalization and 3.54 (95% CI 1.46-8.62) for mortality.
Interpretation of results: These data suggest that the dietary advice for sodium intake should not be below 2 gr/day, as suggested by the European Guidelines of Cardiology. Although, one randomized trial included in the meta-analysis by DiNicolantonio was referred in the latter guideline, the common advice on sodium restriction was not adjusted. This may be because the idea of abandoning the decennia-lasting practice of sodium restriction conflicts with physiologists’ model of high pre- and afterload as causes of morbidity and mortality in chronic HF. However, other mechanisms such as hyponatraemie and neurohumoral activation may be more important in determining outcome in HF patients. Paterna et al. showed that, in contrast with a normal sodium diet, a low-sodium diet increased brain natriuretic peptide, plasma renin activity and aldosterone concentrations. Furthermore, serum sodium concentration significantly decreased despite fluid restriction of 1 l/day.
Conclusion: In patients with chronic HF, available evidence should lead to a recommendation against strict sodium restriction of < 2 gr/day. Whether an upper-limit of sodium intake can be advised, remains to be investigated by randomized trials.
