MICROALBUMINURIA IS ASSOCIATED WITH SALT SENSITIVITY IN HYPERTENSIVE PATIENTS

We have investigated 59 patients with mild-to-moderate uncomplicated e ssential hypertension in order to estimate whether salt sensitivity is associated with greater urinary albumin excretion. Patients whose ave rage mean blood pressure (BP) value on day 5 of the high-sodium regime n (300 mmol/l NaCl) exceeded 10 mm Hg or more than that on day 5 of th e low-sodium regimen (40 mmol/l NaCl) were classified as salt sensitiv e. We have demonstrated that salt sensitive patients (n=29) manifest g reater urinary albumin excretion than salt resistant patients (51.5 +/ - 15 vs 11.5 +/- 12.8 mg/24h). Hypertensive patients selected as salt sensitive had a longer duration of hypertension (87.5 +/- 62 vs 41.5 /- 33.6 months); greater body mass index (BMI) (29.0 +/- 4.7 vs 24.7 /- 3.6 kg/m(2)); lower urinary excretion of sodium after 3 days of sod ium loading (172.1 +/- 23.3 vs 245.8 +/- 21.6 mmol/day); and slightly, but significantly higher mean BP (121.3 +/- 7.4 vs 115.3 +/- 5.3 mmHg ) than salt resistant patients (n=29). Nevertheless, there was no sign ificant correlation between duration of hypertension and the degree of urinary albumin excretion in salt sensitive patients. On the other ha nd, a significant correlation was demonstrated in a group of salt resi stant hypertensive patients, suggesting that salt sensitivity could be linked with an early tendency to abnormal albumin excretion, while in salt resistant patients it may depend on hypertension-related renal d isfunction. Therefore, measurement of microalbuminuria in patients wit h essential hypertension can be a useful marker for salt sensitivity.