Abstract-Race has been considered an important factor in determining blood pressure response to treatment and selection of antihypertensive drug therapy. Data collected during a clinical trial that evaluated rapidity of medication up-titration with blood pressure response to monotherapy with the angiotensin-converting enzyme (ACE) inhibitor quinapril were used to characterize response in 533 black and 2046 white participants. Our objectives were to examine the influence of race and other factors on blood pressure response and to assess the degree to which nonrace factors account for apparent racial differences in response. Average systolic and diastolic blood pressure responses (baseline minus follow-up) to treatment were assessed with treatment groups combined. Crude systolic and diastolic blood pressure responses averaged 4.7 and 2.4 mm Hg less, respectively, in black compared with white participants; however, the response distributions largely overlapped. In multivariate linear regression models adjusted for study design variables and measured participant characteristics, the racial difference in systolic response was reduced by 51% to 2.3 mm Hg, and diastolic response by 21% to 1.9 mm Hg. In these models, participant characteristics, including age, gender, body size, and pretreatment blood pressure severity, significantly predicted either attenuated or enhanced blood pressure response to treatment. Our findings demonstrate that a large source of variability of blood pressure response to treatment is within, not between, racial groups, and that factors that vary at the level of the individual contribute to apparent racial differences in response to treatment. Key Words: ACE inhibitors Ⅲ antihypertensive therapy Ⅲ blood pressure response Ⅲ hypertension Ⅲ race R ace has long been considered an important factor in determining blood pressure (BP) response to treatment, at least to single antihypertensive drugs. [1][2][3][4] More specifically, blacks with hypertension have been reported to be less responsive to monotherapy with angiotensin-converting enzyme (ACE) inhibitors, 5 -blockers, 6 -8 and angiotensin receptor blockers 9 than to diuretics and calcium antagonists. Many of these same studies have reported that white hypertensive patients respond better to these antihypertensive agents than do blacks. 10,11,1,3,4 Authoritative treatment guidelines such as the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure 12 have acknowledged this evidence of lesser BP response among blacks to certain drug classes and have not dismissed the notion that race be considered when selecting antihypertensive drug therapy.There are concerns, however, with the interpretation of data from these studies. First, black and white hypertensives typically differ on baseline characteristics 13,14 that may confound racial differences in BP response; observed response differences have almost never been adjusted for potential confounding factors other than baseline BP. Second, when racial BP ...
