Increased urine albumin excretion (UAE) in salt-sensitive (SS) patients with hypertension (EH).

We previously showed increased glomerular capillary pressure in SS hypertensives and suggested that this may underlie the greater propensity of these patients to develop renal failure. In this study, we have tested whether an association exists between salt-sensitivity and risk of renal disease, determined by UAE. To determine salt-sensitivity, patients were given a diet containing a low (10 mEq/day) Na+ intake for 1 week followed by a high (250 mEq/day) Na+ intake for 1 more week. Sodium sensitivity index was calculated as the ratio of the changes in mean arterial pressure (MAP) to the changes in urine Na+ from the low to the high Na+ intake. Thirty-four patients were classified as SS, and 62 as salt-resistant (SR). Age (47±1.7 vs. 46±1.2 years), and body-mass index (26±0.4 vs. 25±0.4 Kg/m2) were similar between SS and SR. During high Na+ intake, MAP increased by 16±0.8 mm Hg in SS and by 2.9±0.5 mm Hg in SR. UAE was higher in SS than in SR (36.2±4.2 vs. 16.3±1.9 mg/24 hr; P<0.001). A significant correlation was present between salt-sensitivity index and UAE (r=0.50; P<0.0001). These studies have shown greater UAE in SS hypertensive patients, suggesting that these patients may be at greater risk of renal complications as a consequence of hypertension.