Salt is not the only factor: Races respond differently to blood pressure treatment

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Salt is not the only factor: RACES RESPOND DIFFERENTLY TO HIGH BLOOD PRESSURE TREATMENT

Significant racial differences in response to high blood pressure medications persist even when the variable of salt sensitivity is controlled, says a University of Maryland School of Medicine researcher. Up to now, the difference in salt sensitivity among races was believed to be the only factor influencing the effectiveness of different medications in lowering blood pressure in African Americans, Hispanic Americans and Caucasians.

At the American Society of Hypertension scientific meeting in San Francisco May 27-31, 1997, Dr. Matthew R. Weir will present findings from a clinical trial involving two of the most common kinds of blood pressure medication. A professor of medicine and head of the Division of Nephrology at the University of Maryland School of Medicine in Baltimore, Weir authored the multi-center study, which compared the blood pressure-lowering effects of enalapril, an angiotensin converting enzyme (ACE) inhibitor, and the calcium channel antagonist isradipine during high and low salt intake.

Nearly 400 African Americans, Hispanic Americans and Caucasians with high blood pressure who also were known to be salt-sensitive were studied. Weir and colleagues found that isradipine lowered blood pressure more effectively in African Americans on a high salt diet, while both drugs worked equally well for African Americans on a low salt diet. In Caucasians, both medications produced similar blood pressure reduction on a high salt diet, but enalapril was more effective for Caucasians who restricted their salt intake. In Hispanic-Americans, both drugs lowered blood pressure to similar levels on both high and low salt diets.

"Our results show that there are issues other than salt sensitivity in the racial differences we see in response to antihypertensive medications," Weir said. "We controlled for salt sensitivity, and racial differences - although lessened - persisted. This reinforces the importance of dietary salt restriction for people of all races who have high blood pressure."

In another presentation at the hypertension meeting, Weir will discuss the relationship of high blood pressure to kidney disease. "We are now observing that more aggressive treatment of hypertension can be both safe and effective in preventing kidney damage," he said.