Significant racial differences in response to high blood pressuremedications persist even when the variable of salt sensitivity iscontrolled, says a University of Maryland School of Medicineresearcher. Up to now, the difference in salt sensitivity among raceswas believed to be the only factor influencing the effectiveness ofdifferent medications in lowering blood pressure in African Americans,Hispanic Americans and Caucasians.
At the American Society of Hypertension scientific meeting in SanFrancisco May 27-31, 1997, Dr. Matthew R. Weir presented findingsfrom a clinical trial involving two of the most common kinds of bloodpressure medication. A professor of medicine and head of the Divisionof Nephrology at the University of Maryland School of Medicine inBaltimore, Weir authored the multi-center study, which compared theblood pressure-lowering effects of enalapril, an angiotensinconverting enzyme (ACE) inhibitor, and the calcium channel antagonistisradipine during high and low salt intake.
Nearly 400 African Americans, Hispanic Americans and Caucasians withhigh blood pressure who also were known to be salt-sensitive werestudied. Weir and colleagues found that isradipine lowered bloodpressure more effectively in African Americans on a high salt diet,while both drugs worked equally well for African Americans on a lowsalt diet. In Caucasians, both medications produced similar bloodpressure reduction on a high salt diet, but enalapril was moreeffective for Caucasians who restricted their salt intake. InHispanic-Americans, both drugs lowered blood pressure to similarlevels on both high and low salt diets.
"Our results show that there are issues other than salt sensitivity inthe racial differences we see in response to antihypertensivemedications," Weir said. "We controlled for salt sensitivity, andracial differences - although lessened - persisted. This reinforcesthe importance of dietary salt restriction for people of all races whohave high blood pressure."
In another presentation at the hypertension meeting, Weir discussed the relationship of high blood pressure to kidney disease. "We arenow observing that more aggressive treatment of hypertension can beboth safe and effective in preventing kidney damage," he said.
Materials provided by University of Maryland at Baltimore. Note: Content may be edited for style and length.
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