Using a Salt Substitute Associated with Significant Reduction in Stroke and Death in Those with a History of Stroke

Replacing salt with a salt substitute in home cooking may significantly reduce risk of recurrence and all-cause mortality for people who have a history of stroke, according to data published in JAMA Neurology. Findings from a prespecified, secondary subgroup analysis of the China Salt Substitute and Stroke Study (SaSS; NCT02092090) suggest that salt substitution in diet may be a cost-effective and scalable method to improve cardiovascular health without increasing risk of hyperkalemia.

SaSS was an open-label, cluster-randomized clinical trial conducted in 600 villages across 5 provinces in northern China. A total of 20,995 participants were randomized 1:1 to either receive a salt substitute (containing 75% sodium chloride, 25% potassium chloride) to completely replace their use of salt in home cooking (300 villages, n=10,504), or to continue cooking with regular salt (300 villages, n=10,491). The prespecified subgroup analysis included 15,249 participants with a history of stroke who were evaluated over a median follow-up period of 61.2 months based on routinely collected health data or face-to-face visits every 6 months. Study outcomes, including the primary endpoint of stroke incidence and secondary endpoints of total major vascular events and total mortality, were adjudicated by a blinded committee.

Key results include the following:

• The recurrent stroke rate was 16.8% in the salt substitute group and 19.1% in the regular salt group (rate ratio [RR], .86; 95% CI, .77 to .95; P=.005), corresponding to a 14% relative reduction for salt substitution.
• Salt substitution was associated with a greater reduction in hemorrhagic stroke (relative reduction, 30%; 95% CI, .56 to .87; P=.002) compared with ischemic stroke (relative reduction, 8%; 95% CI, .81 to 1.04; P=.19).
• People who used the salt substitute experienced a 12% reduction in total mortality (RR, .88; 95% CI, 4% to 18%; P=.003) and a 21% reduction in stroke-related deaths (95% CI, 5% to 33%; P=.01).
• Hyperkalmeia risk was not significantly different across the 2 diet groups (RR, 1.01; 95% CI, .74 to 1.38; P=.96).

The authors of the article note that the open-label format of the SaSS study, the exploratory nature of secondary subgroup analyses, and the restriction to rural northern China are limitations on their study.