There Are No Racial, Age, Sex, or Weight Differences in the Effect of Salt on Blood Pressure in Salt-Sensitive Hypertensive Patients

Background:

This report is part of a larger, multicenter, placebo-controlled study designed to test the effects of low and high salt intake on the antihypertensive action of enalapril maleate or isradipine in salt-sensitive, hypertensive patients.

Objective:

To present our findings with respect to the effects of race, age, sex, and weight on the blood pressure response to low and high salt intake in salt-sensitive hypertensive patients before randomization into the larger study.

Patients and Methods:

After 3 weeks (weeks —9 to —6) of ad lib salt intake (100-200 mmol/d of sodium), 1916 patients whose sitting diastolic blood pressure was between 95 and 115 mm Hg entered a 3-week period (week —6 to —3) of low salt intake (50-80 mmol/d of sodium) and then a 3-week period (week —3 to 0) of high salt intake (200-250 mmol/d of sodium). Of the 1916 patients, 624 were identified as being sensitive to salt by demonstrating an increase in sitting diastolic blood pressure of equal to or more than 5 mm Hg from the low to high salt intake. Of these patients, 367 were white, 156 were black, 92 were Hispanic, 8 were Asian, and 1 was American Indian. Also, 315 were men and 309, women; 351 were 55 years or younger and 273 were older than 55 years; and 195 had a body mass index of 27 or less and 429 had a body mass index higher than 27.

Results:

The sitting blood pressure decreased with salt restriction and increased with salt load in all groups of patients (P<.001). There were no statistically significant differences in the blood pressure changes to salt changes by race, age, sex, and weight.

Conclusions:

This large, multicenter study did not demonstrate any statistically significant effect of race, age, sex, and weight on blood pressure response to salt changes in salt-sensitive hypertensive patients. Arch Intern Med. 1997;157:2489-2494