Salt Sensitivity and Nondippers in Chronic Kidney Disease

Abstract

High salt-sensitivity and nondipper blood pressure (BP) rhythm are highly associated with each other, because both are caused by impaired renal sodium excretion capability. We proposed that nocturnal hypertension and resultant pressure natriuresis could compensate for daytime sodium retention. If so, high BP may continue until sodium is sufficiently excreted at night. In fact, it takes longer for the night-time BP to fall in patients with more severe renal dysfunction. The time appears to be an essential component of the nondipper BP rhythm and, therefore, we defined the duration as the dipping time. Also, renal function was the sole determinant of a nocturnal BP dip other than age, sex, or BMI. Furthermore, we reported that diuretic therapy or dietary salt restriction, which can prevent sodium retention, restored the circadian BP rhythm into a dipper pattern. Large-scale studies are needed to explore whether these interventions can decrease the risks.