Switching to a salt substitute reduced stroke risk by 14%

Switching from regular salt to a salt substitute reduced the risk of stroke, major CV events, and death in a large-scale trial of adults in rural China with a history of stroke or stroke. high risk of stroke.

In nearly 21,000 adults and a mean follow-up of 4.74 years, the stroke rate was 14% lower with the use of a salt substitute compared to regular salt (29.14 vs. 33.65 events per 1000 person-years; RR = 0.85; 95% CI, 0.77-0.96; P = .006).

The results of the Salt Substitute and Stroke Study (SaSS) were presented at the congress of the European Society of Cardiology and simultaneously published in The New England Journal of Medicine.

“The rationale for salt substitutes is that higher dietary sodium intake and lower dietary potassium intake are associated with high BP levels, and salt substitutes fortified with potassium have a dual reduction effect. PA ” Bruce Neal, MB, ChB, PhD, scientific director of the George Institute for Global Health, said at a press conference. “Before doing the SSaSS, we had pretty good evidence that salt substitutes lowered BP, but we lacked data on their effect on strokes and heart attacks. There were also concerns about supplementing people’s diets with potassium, as it could cause hyperkalemia in people with severe kidney disease.

Proof of CV protection

The open-label, randomized cluster trial recruited 20,995 adults from rural villages in China who had a history of stroke or were aged 60 and over and had high BP. The average age of participants was 65, 49.5% were female, 72.6% had a history of stroke, and 88.4% had hypertension.

Participants were randomly assigned to use common salt or a salt substitute consisting of 70% sodium chloride and 25% potassium chloride. Participants were asked to use regular salt as they usually would or to use the salt substitute in place of common salt for cooking, seasoning and preserving food, more sparingly than their previous use of common salt.

In addition to the reduction in the primary endpoint of stroke, the rate of major adverse CV events, a composite of non-fatal stroke, non-fatal acute coronary syndrome, or death from vascular causes, was 13% lower among participants in the salt replacement group (49.09 events versus 56.29 events per 1,000 person-years; RR = 0.87; 95% CI: 0.8-0.94; P <.001). All-cause mortality was 12% lower in the salt replacement group (39.28 events versus 44.61 events per 1,000 person-years; RR = 0.88; 95% CI: 0.82-0, 95; P <.001).

The researchers calculated a different mean systolic BP of –3.34 mm Hg).

There was no difference between groups in the rate of serious adverse events attributed to hyperkalemia.

“Intriguing clues” of advantages

The study is one of the largest dietary intervention trials conducted, Neal said.

“The key question is whether the results of the SSaSS, carried out in China, are likely to be generalizable to other populations,” said Neal. “The answer to that is almost certainly yes. The way the body deals with sodium, potassium, associations with BP, are very consistent among various populations around the world.

Julie R. Ingelfinger

In a related editorial, Julie R. Ingelfinger, MD, professor of pediatrics at Harvard Medical School, senior consultant in pediatric nephrology and pediatrician at Massachusetts General Hospital for Children and Massachusetts General Hospital, and associate editor of NEJM, noted that processed foods are rarely used in rural Chinese villages studied in the SSaSS; Dietary sodium chloride is added during food preparation in every household – a stark contrast to typical Western diets.

“Commercial food preservation adds a lot of sodium chloride to the diet, and the use of salt substitutes wouldn’t even begin to account for the bulk of salt intake,” Ingelfinger wrote.

Calling the results impressive, Ingelfinger wrote that the salt substitute approach could have a major public health consequence in China, and possible elsewhere, if the strategy is feasible over time.

“Overall, SSaSS provides some intriguing clues, but broader effectiveness is difficult to predict, given the limited generalization,” Ingelfinger wrote.

The references:

Perspective

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Eva Prescott, MD, DMSc, FESC

It’s a great trial. The authors are to be congratulated for having carried out a cluster-randomized trial in 600 villages and including more than 20,000 people with previous stroke or aged at least 60 years with poorly controlled hypertension. Participants were followed for an average of 5 years for significant concrete results and the study appears to be of high quality and meticulously conducted. The results show that the study participants were compliant – a reduction in sodium secretion and an increase in potassium secretion – and had a reduction in BP and a significant and clinically relevant reduction in primary and secondary outcomes. . Notably, there did not appear to be a risk of hyperkalemia, which was a concern when switching from sodium to potassium.

The study confirms that the reduction in BP can be achieved by replacing sodium with potassium and – novelty here – that this also translates into outcome benefits, both for stroke and mortality. all causes combined. There was also an unexpected effect on non-vascular mortality, but this may be related to the imprecise recording of the cause of death in some cases, as the authors noted.

The implications of the trial are that salt substitution should probably be implemented much more than at present, especially in areas where medical treatment is not optimal. However, the intervention only targeted people with poorly controlled BP or stroke and people with impaired kidney function were excluded. It is therefore not known whether this approach can be generalized to the entire population. Thus, simple implementation in entire populations can be tricky.

Eva Prescott, MD, DMSc, FESC

Professor of Cardiology

Head of the Cardiovascular Research Center

Bispebjerg Frederiksberg Hospital

University of copenhagen

Disclosures: Prescott does not report any relevant financial disclosure.

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