One of the late-breaking trials presented during the virtual European Society of Cardiology (ESC) Congress 2021 held in late August was the Salt Substitute and Stroke Study (SSaSS), which was simultaneously published in New England Journal of Medicine. Formerly, salt substitutes with reduced sodium levels and increased potassium levels have been shown to lower blood pressure, but their effects on cardiovascular and safety outcomes remained uncertain.
The SSaSS trial was an open-label, cluster-randomized trial involving persons from 600 villages in rural China. The participants had a history of stroke or were 60 years of age or older and had high blood pressure. The villages were randomly assigned in a 1:1 ratio to the intervention group, in which the participants used a salt substitute (75% sodium chloride and 25% potassium chloride by mass), or to the control group, in which the participants continued to use regular salt (100% sodium chloride). The primary outcome was stroke, the secondary outcomes were major adverse cardiovascular events and death from any cause, and the safety outcome was clinical hyperkalemia.
A total of 20,995 persons were enrolled. The mean age of the participants was 65.4 years, 49.5% were female, 72.6% had a history of stroke, and 88.4% had hypertension. The mean duration of follow-up was 4.74 years. The rate of stroke was lower with the salt substitute than with regular salt (29.14 events vs. 33.65 events per 1000 person-years; rate ratio, 0.86; 95% confidence interval [CI], 0.77 to 0.96; P=0.006), as were the rates of major cardiovascular events (49.09 events vs. 56.29 events per 1000 person-years; rate ratio, 0.87; 95% CI, 0.80 to 0.94; P<0.001) and death (39.28 events vs. 44.61 events per 1000 person-years; rate ratio, 0.88; 95% CI, 0.82 to 0.95; P<0.001). The rate of serious adverse events attributed to hyperkalemia was not significantly higher with the salt substitute than with regular salt (3.35 events vs. 3.30 events per 1000 person-years; rate ratio, 1.04; 95% CI, 0.80 to 1.37; P=0.76).
The salt substitute used in this trial is of low cost and easy to manufacture. Therefore, the study results should have major implications for the food industry as well as for policy makers.
Reference: https://www.nejm.org/doi/full/10.1056/NEJMoa2105675
