Diet, ExerCIse and carDiovascular hEalth (DECIDE) - Salt Reduction Strategies for the Elderly in Nursing Homes in China

The DECIDE - Salt in Elderly (Diet, ExerCIse and carDiovascular hEalth - Salt Reduction Strategies for the Elderly in Nursing Homes in China) is to evaluate the effects, safety and cost-effectiveness of salt substitution (SS) and stepwise salt supply control (SSSC) in reducing blood pressure in Chinese elderly in nursing homes. The study will recruit over 960 old people from 48 nursing homes in northern China. The 48 nursing homes will be randomised into the following 4 groups. 1. salt substitute (SS) and stepwise salt supply control (SSSC); 2. SS only; 3. SSSC only; and 4. no SS and no SSSC (control). The intervention will last over 2 years. The randomization will be conducted centrally after the baseline survey completed. Primary outcome will be the change in systolic blood pressure. The secondary outcomes include: the changes in diastolic blood pressure, 24hr urinary sodium, potassium and microalbumin, and incidence of hyperkalemia, hypokalemia, hyponatremia, cardiovascular events, and all causes death, and incremental cost-effectiveness ratio.