Hot Line - Use of salt substitutes reduces CV events and death

29 Aug 2021

The use of potassium chloride-containing salt substitutes to reduce dietary sodium intake are effective in lowering blood pressure (BP)¹ but their impact on cardiovascular (CV) events is unclear. There are also some concerns regarding salt substitute-associated hyperkalaemia and its sequelae in people with chronic kidney disease.

In a Hot Line session today, Professor Bruce Neal (The George Institute for Global Health, Sydney, Australia) presented results from the Salt Substitute and Stroke Study (SSaSS), which compared the effects of reduced-sodium salt substitute with regular salt.

Adults with previous stroke or aged at least 60 years and with poorly controlled BP were recruited from 600 villages in rural areas of China. Participants were cluster-randomised by village in a 1:1 ratio to receive regular salt or salt substitute (around 75% sodium chloride and 25% potassium chloride). The primary outcome was stroke and the two secondary outcomes were major CV events (non-fatal stroke, non-fatal acute coronary syndrome and vascular death) and total mortality.

A total of 20,995 participants – mean age 65.4 years – were recruited, 72.6% with a history of stroke and 88.4% with a history of hypertension. Approximately half (49.5%) were female.

During an average follow-up of 4.74 years, salt substitute reduced the risk of stroke compared with regular salt (29.14 vs. 33.65 per 1,000 patient-years; rate ratio [RR] 0.86; 95% confidence interval [CI] 0.77 to 0.96; p=0.006).

Salt substitute also reduced secondary outcomes, with fewer major CV events (49.09 vs. 56.29 per 1,000 patient-years; RR 0.87; 95% CI 0.80 to 0.94; p<0.001) and lower total mortality (39.27 vs. 44.61 per 1,000 patient-years; RR 0.88; 95% CI 0.82 to 0.95; p<0.001). 

There was no increased risk of serious adverse events attributed to clinical hyperkalaemia with salt substitute compared with regular salt (3.35 vs. 3.30 per 1,000 patient-years; RR 1.04; 95% CI 0.80 to 1.37; p=0.76). No other risks were identified.

Commenting on these encouraging findings, Prof. Neal said, “This study provides clear evidence about an intervention that could be taken up very quickly at very low cost. The trial result is particularly exciting because salt substitution is one of the few practical ways of achieving changes in the salt people eat. Other salt reduction interventions have struggled to achieve large and sustained impact.’’ Noting that salt substitute could provide benefits for people around the world, Prof. Neal added, “It is primarily lower-income and more disadvantaged populations that add large amounts of salt during food preparation and cooking.² This means that salt substitute has the potential to reduce health inequities related to cardiovascular disease.”

 

Missed the session? Watch it on demand:

https://digital-congress.escardio.org/ESC-Congress/sessions/2838-hot-line-ssass

 

See also the Late-Breaking Trial, DECIDE-Salt:

https://digital-congress.escardio.org/ESC-Congress/sessions/2607-late-breaking-trials-in-hypertension