A meta-analysis confirms benefits for blood pressure reduction and clinical outcomes seen in the large SSaSS trial. 

Hypertension remains a leading cause of morbidity and mortality throughout the world. Several studies, including the Salt Substitute and Stroke Study (SSaSS; N Engl J Med 2021; 385: 1067-1077) indicate benefits of salt substitutes for blood pressure reduction and clinical outcomes. To assess whether these benefits are consistent across all available trials, researchers conducted a meta-analysis of 21 trials of salt substitutes that included 31,949 participants.

The SSaSS study alone contributed 20,995 participants and most of the clinical outcomes. Nineteen trials reported blood pressure effects and five reported clinical outcomes. The interventions varied, with the proportion of potassium chloride in the salt substitute varying from 25 to 65%. The mean baseline systolic blood pressure ranged from 113 mmHg to 177 mmHg.

Salt substitutes were associated with reductions of 4.6 mmHg in systolic blood pressure and 1.6 mmHg in diastolic blood pressure. The effect was generally consistent across subgroups (including geographical region). A lower proportion of sodium chloride in the substitute was associated with a greater blood pressure reduction. Salt substitutes reduced the risk for all- cause death by 11%, vascular death by 13% and major adverse cardiovascular events by 11%. Hyperkalaemia events were not significantly more common with salt substitute.

Comment: This meta-analysis, and especially the SSaSS trial, supports the inclusion of salt substitutes as an option for eligible patients with hypertension. Moreover, this strategy may be particularly useful in resource-poor settings and where there is high baseline salt intake. Few dietary interventions have this strength of evidence relating to improved outcomes. Of note, the DASH diet is also supported by evidence of blood pressure lowering in randomised controlled trials and is potentiated by a low-sodium diet.
HARLAN M. KRUMHOLZ, MD, SM
Harold H. Hines, Jr. Professor of Medicine, Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, USA.

Yin X, et al. Effects of salt substitutes on clinical outcomes: a systematic review and meta-analysis. Heart 2022 Aug 9; e-pub (https://doi.org/10.1136/heartjnl-2022-321332).

This summary is taken from the following Journal Watch title: General Medicine.