A systematic review conducted by Kamal R. Mahtani et al in JAMA looked into the evidence of salt restriction recommendation on heart failure prognosis. The investigators evaluated previous trials but could not find a conclusive relationship between salt consumption and heart failure prognosis.
Heart failure medical management is stable, however, the lifestyle modifications and recommendations including salt restriction have been controversial. Some randomized clinical trials proposed that salt restriction may worsen the heart failure. Although a lot of guidelines are suggestive of restricting patients with heart failure on salt consumption, these suggestions are not based on evidence-based studies.
Mahtani et al brought up the question of whether currently published studies could demonstrate the effectiveness of salt restriction on heart failure prognosis. Out of multiple studies, they included studies with chronic stable heart failure outpatients and acutely decompensated heart failure admitted patients in their systematic review. Their study included 9 studies involving 479 participants. They defined two sets of outcomes as the primary outcomes including cardiovascular-associated mortality, all-cause mortality, and adverse events (eg, stroke, myocardial infarction, hyponatremia, and hypernatremia) and the secondary outcomes included hospitalization, length of inpatient stay, change in clinical signs and symptoms of heart failure, measurement, and adherence to low dietary salt intake, and change in blood pressure.
They demonstrated that their systematic review did not find enough evidence on the effectiveness of reduced dietary salt intake on cardiovascular-associated or all-cause mortality, cardiovascular-associated events, hospitalization, or length of hospital stay. They mentioned that based on 3 studies they include, an improvement trend in the clinical signs and symptoms of heart failure was shown by reducing dietary salt intake. The previous studies including meta-analysis were unable to show a meaningful relationship between low sodium intake and better prognosis of heart failure. Mahtani suggested that as the suggestion to decrease sodium intake is broadly used among physicians and even on guidelines, it is important to conduct a broad study to evaluate the effect.