Interim effects of salt substitution on urinary electrolytes and blood pressure in the China Salt Substitute and Stroke Study (SSaSS)

Liping Huang, Maoyi Tian, Jie Yu, Qiang Li, Yishu Liu, Xuejun Yin, Jason HY Wu, Matti Marklund, Yangfeng Wu, Nicole Li, Paul Elliott, Lijing L. Yan, Darwin R. Labarthe, Zhixin Hao, Jingpu Shi, Xiangxian Feng, Jianxin Zhang, Yuhong Zhang, Ruijuan Zhang, Bo ZhouZhifang Li, Jixin Sun, Yi Zhao, Yan Yu, Bruce Neal*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The Salt Substitute and Stroke Study is an ongoing 5-year large-scale cluster randomized trial investigating the effects of potassium-enriched salt substitute compared to usual salt on the risk of stroke. The study involves 600 villages and 20,996 individuals in rural China. Intermediate risk markers were measured in a random subsample of villages every 12 months over 3 years to track progress against key assumptions underlying study design. Measures of 24-hour urinary sodium, 24-hour urinary potassium, blood pressure and participants’ use of salt substitute were recorded, with differences between intervention and control groups estimated using generalized linear mixed models. The primary outcome of annual event rate in the two groups combined was determined by dividing confirmed fatal and non-fatal strokes by total follow-up time in the first 2 years. The mean differences (95% CI) were -0.32 g (-0.68 to 0.05) for 24-hour urinary sodium, +0.77 g (+0.60 to +0.93) for 24-hour urinary potassium, -2.65 mmHg (-4.32 to -0.97) for systolic blood pressure and +0.30 mmHg (-0.72 to +1.32) for diastolic blood pressure. Use of salt substitute was reported by 97.5% in the intervention group versus 4.2% in the control group (P<.0001). The overall estimated annual event rate for fatal and non-fatal stroke was 3.2%. The systolic blood pressure difference and the annual stroke rate were both in line with the statistical assumptions underlying study design. The trial should be well placed to address the primary hypothesis at completion of follow-up.

Original languageEnglish (US)
Pages (from-to)136-145
Number of pages10
JournalAmerican heart journal
StatePublished - Mar 2020

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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