In this 2022 systematic review and meta-analysis, 1 Yin et al evaluated 21 trials, including SSaSS, for the effect of salt substitutes on BP and other clinical outcomes, and the generalizability of the study results to diverse populations. The systematic review included parallel-group, step-wedge, and cluster-randomized controlled trials reporting the effect of salt substitutes on BP or clinical outcomes.
STUDY SUMMARY
Salt substitutes reduced BP across diverse populations
This systematic review and meta-analysis reviewed existing literature for randomized controlled trials investigating the effects of potassium-enriched salt substitutes on clinical outcomes for patients without kidney disease. The most commonly used salt substitute was potassium chloride, at 25% to 65% potassium.
The systematic review identified 21 trials comprising 31,949 study participants from 15 different countries with 1 to 60 months’ duration. Meta-analyses were performed using 19 trials for BP outcomes and 5 trials for vascular outcomes. Eleven trials were rated as having low risk for bias, 8 were deemed to have some concern, and 2 were rated as high risk for bias. Comparisons of data excluding studies with high risk for bias yielded results similar to comparisons of all studies.
The meta-analysis of 19 trials demonstrated reduced SBP (–4.6 mm Hg; 95% CI, –6.1 to –3.1) and DBP (–1.6 mm Hg; 95% CI, –2.4 to –0.8) in participants using potassium-enriched salt substitutes. However, the authors noted substantial heterogeneity among the studies (I 2 > 70%) for both SBP and DBP outcomes. Although there were no subgroup differences for age, sex, hypertension history, or other biomarkers, outcome differences were associated with trial duration, baseline potassium intake, and composition of the salt substitute.
Potassium-enriched salt substitutes were associated with reduced total mortality (risk ratio [RR] = 0.89; 95% CI, 0.85-0.94), CV mortality (RR = 0.87; 95% CI, 0.81-0.94), and CV events (RR = 0.89; 95% CI, 0.85-0.94). In a meta-regression, each 10% reduction in the sodium content of the salt substitute was associated with a 1.5–mm Hg greater reduction in SBP (95% CI, –3.0 to –0.03) and a 1.0–mm Hg greater reduction in DBP (95% CI, –1.8 to –0.1). However, the authors suggest interpreting meta-regression results with caution.
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