Abstract
BACKGROUND: Hypertension is the leading risk factor for cardiovascular disease worldwide. Patients with blood pressure (BP) response to dietary sodium reduction are referred to as "salt sensitive." Salt sensitivity (SS) might be due to differences in sodium storage capacity and the erythrocyte SS examines this capacity of the red blood cells. This study aimed to test the effect of a self-performed sodium reduced diet on BP in patients with essential hypertension and examine whether erythrocyte SS predicts SS. METHODS AND RESULTS: Seventy-two patients with hypertension were included and randomized 2:1 to either sodium reduction or a control group for 4 weeks. Blood samples, 24-hour BP measurement, and 24-hour urine collection were performed before and after. The intervention group received advice on how to lower sodium intake. Urinary sodium excretion decreased 66 mmol (95% CI, -96 to -37 mmol) in the intervention group compared with the control group. Systolic 24-hour BP decreased 9 mm Hg after low-sodium diet compared with the control group (95% CI, -13 to -4 mm Hg). Similarly, the difference in reduction in diastolic BP between the groups was 5 mm Hg (95% CI, -8 to -1 mm Hg). We found no correlation between erythrocyte SS at baseline and decrease in 24-hour BP, neither systolic nor diastolic (P=0.66 and P = 0.84). CONCLUSIONS: Self-performed sodium reduction was feasible and led to decrease in 24-hour BP of 9/5 mm Hg compared with a control group. The erythrocyte SS did not correlate to the change in BP after lowering sodium intake. REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: NCT05165823.