China Salt Substitute Study

This randomised trial will clearly identify whether a low-sodium, high-potassium salt-substitute is a feasible means of lowering blood pressure in high-risk individuals in rural China. The randomised design and the large size (n=600) will ensure that the results are reliable and precise. The 12-month duration will address the long-term practicability of the intervention strategy. The study is being conducted because salt-substitute-based blood pressure lowering may be particularly appropriate for rural populations in low- and middle-income countries. First, sodium intake is often very high. Second, the salt-substitute can be easily incorporated into the diet because most food is prepared and eaten at home. Third, the intervention can be provided at very low cost.

Comparisions: Low sodium high potassium salt (65% sodium chloride, 25% potassium chloride, 10% magnesium sulphate) compared to normal salt (100% sodium chloride).

Inclusion criteria

Participant inclusion will be based upon the presence of:

• A doctor-confirmed high risk of future vascular disease defined as a history of any one of:

• Stroke or transient ischaemic attack
• Hospitalisation for management of any acute coronary syndrome
• Surgery or angioplasty for peripheral vascular disease
• Treated diabetes and age 55 years or older
• Systolic blood pressure >160mmHg
• Estimated daily sodium intake of 260mmol/24hrs (about 15g/24hrs of NaCl) or above and expectation that at least 50% of daily dietary salt intake can be replaced with the salt-substitute. This will be estimated through interview of the potential participant and the individual responsible for daily food preparation (if this is not the patient) using a structured questionnaire.
• Provision of informed consent

Exclusion criteria

Potential participants will be excluded if:

• they are on potassium-sparing medication
• there is an established history of significant renal impairment that would preclude the use of the salt-substitute in the opinion of the responsible physician.
• there is any reason why either the salt-substitute or normal salt are definitely indicated or definitely contra-indicated.