OBJECTIVE: To observe the long-term (3 years) consumption of enriched potassium salt (KCL/NaCL = 1:1 by weight) on all causes mortality and target organ damage in Chinese living in nursing houses.
DESIGN AND METHOD: The study was designed as a single blind prospective intervention. Participants were living in 22 nursing houses in northern China. The nursing houses were randomized into 2 groups: normal salt (control group) and enriched potassium salt (intervention group). The study salt was calculated and dispensed to each nursing house every 3 months. The six-time follow-up visits were carried out during 3 years. Items of the follow-up included questionnaire, physical examination, blood sample and spot urine collection. Data of people moving in or out and of death were collected. The mortality was calculated by observed person-year (p-y).
RESULTS: Totally 1839 people (intervention group 1032, control 807) were analyzed. The baselines of age, SBP, DBP, and urinary sodium to potassium ratio (UNa/K) were not different between control and intervention groups. After using study salt for 3 years, the mean age, blood pressure and UNa/K are listed below. The proportion of impaired kidney function (ratio of microalbumin to creatinine> = 30 mg/g) was 26.8% and 16.2% for control and intervention group respectively (Chi square = 21.683, P < 0.001). The all causes mortality was 82.73/1000 p-y and 48.90/1000 p-y for control and intervention group respectively (Chi square = 28.626, p = 0.000).
CONCLUSIONS: The results demonstrate a beneficial effect of long term enriched K salt consumption on all causes mortality. This might be due to its effect on the blood pressure lowering and/or the beneficial effect on kidney function induced by potassium substitution. Further implementation study of enriched K salt in general population is expected.