Substituting salt with a low-sodium alternative in 600 rural villages across five provinces in China decreased rates of stroke, major cardiovascular events, and death from any cause in individuals with a history of stroke or who were 60 years of age or older with hypertension. The findings from the Salt Substitute and Stroke Study (SSaSS), presented during ESC Congress 2021 and simultaneously published in the New England Journal of Medicine (NEJM), could have benefits for other countries in Asia, Africa and Latin America in which salt intake is above recommended levels.

Researchers cluster-randomized 20,995 participants by village (two in each province) in a 1:1 ratio to either use of a salt substitute or continued use of regular salt. Those participants in intervention villages were given free salt substitute to cover the needs of their entire household as a replacement for regular salt in all cooking, seasoning and food preservation. Participants in control villages continued their usual habits. The primary outcome was stroke, followed by secondary outcomes of major adverse cardiovascular events and death from any cause. The safety outcome was clinical hyperkalemia.

Overall results found the risk of stroke was reduced with use of the salt substitute compared with regular salt use (29.14 vs. 33.65 per 1,000 patient-years). Major cardiovascular events were also reduced with salt substitute (49.09 vs. 56.29 per 1,000 patient-years), along with total mortality (39.27 vs. 44.61 per 1,000 patient-years). Additionally, researchers observed no increased risk of serious adverse events attributed to clinical hyperkalemia in the salt substitute group compared with the regular salt group.

"This study provides clear evidence about an intervention that could be taken up very quickly at very low cost," said principal investigator Bruce Neal, MD. "The trial result is particularly exciting because salt substitution is one of the few practical ways of achieving changes in the salt people eat." He added that the findings from the study suggest use of a salt substitute "has the potential to reduce health inequities related to cardiovascular disease."

In a related NEJM editorial, Julie R. Ingelfinger, MD, calls the SSaSS findings "impressive" and notes that if the strategy is feasible over time "the salt substitute approach might have a major public health consequence in China and possibly elsewhere. However, she cautions about some of the study's limitations including the use of only one salt substitute version, the lack of serial monitoring of potassium levels and the possibility that hyperkalemic episodes went undetected. "Overall, the SSaSS provides some intriguing hints," she writes, "but wider effectiveness is hard to predict, given limited generalizability."

Clinical Topics: Prevention

Keywords: ESC Congress, ESC21, Stroke, Blood Pressure, Primary Prevention, ACC International

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