Salt sensitivity of blood pressure in non-dialysis patients with chronic kidney disease

Abstract

Background: Chronic kidney disease (CKD) is a world-wide public health problem. Hypertension is both a cause and a complication of CKD, and a risk factor for progression of kidney disease. The effect of salt intake on blood pressure (BP) and the salt sensitivity in non-dialysis patients with CKD were studied.

Methods: One hundred and thirty non-dialysis patients with CKD were enrolled in the present study. Daily urinary excretion of sodium (representative of daily sodium intake) and BP was monitored in conditions of original eating habits. Estimated glomerular filtration rate (eGFR) was measured by the creatinine clearance (Ccr).

Results: There was a linear positive relationship between the salt intake and systolic blood pressure (SBP) (β = 0.250, p = 0.004). It had been found that the log of BP/24-h urinary sodium (salt sensitivity index) had linear relationship with the log of eGFR (βsyst = -0.364, p = 0.000, βdiast = -0.345, p = 0.000, respectively). Multi-stepwise regression analysis showed SBP was mainly influenced by salt intake and eGFR. There was a negative correlation between diastolic blood pressure (DBP) and age.

Conclusion: These results demonstrated a linear relationship between the salt intake and SBP in non-dialysis patients with CKD. The salt sensitivity of BP rose with the decline of renal function.