November 24, 1997

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

Author Affiliations

From the Oklahoma Cardiovascular and Hypertension Center and the University of Oklahoma, Oklahoma City (Dr Chrysant), the University of Maryland School of Medicine, Baltimore (Dr Weir), the University of Michigan, Ann Arbor (Dr Weder), University of Oregon Health Sciences Center, Portland (Dr McCarron), Miami Heart Research Institute, Miami, Fla (Dr Canossa-Terris), St Louis University Health Sciences Center, St Louis, Mo (Dr Cohen), Sandoz Pharmaceutical Corp, Hanover, NJ (Dr Mennella), Hill Top Research, Tacoma, Wash (Dr Kirkegaard), National Research Institute, Los Angeles, Calif (Dr Lewin), and the University of Indiana School of Medicine, Indianapolis (Dr Weinberger).

Arch Intern Med. 1997;157(21):2489-2494. doi:10.1001/archinte.1997.00440420121013

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 increasein 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