LETTER TO THE EDITOR
Response to renin-angiotensin system antagonists in hypertensive black subjects
Larisa M. Humma, PharmD and
Patricia L. Adenekan, PharmD
University of Illinois at Chicago, College of Pharmacy, Department of Pharmacy Practice, 833 S. Wood, Room 164, Chicago, IL, USA 60612
humma{at}uic.edu
We read with interest the study by Flack et al. (1) which appeared in the April 2, 2003, issue of the Journal. We commend the researchers on investigating the effects of aldosterone antagonism in the black population, who are traditionally underrepresented in clinical trials. However, we have some concerns regarding the characteristics of the study subjects.
First of all, we question the investigators' use of weight, rather than body mass index (BMI), as an anthropometric measurement. Data from the Framingham Heart Study indicate that higher BMI is a major determinant of inadequate blood pressure control with antihypertensive medications (2). Though not statistically different, both male and female subjects in the eplerenone group had greater body weight than did those in the losartan group. Thus, we are curious as to whether BMI differed between treatment groups and, if so, whether these differences may have contributed to the disparity in results between groups.
Second, the study included participants from both the U.S. and Africa. The investigators do not report the percentage of black participants who were from Africa versus those from the U.S. This information is important in conferring the applicability of the study findings to blacks in the U.S. Differences in environmental factors have been reported among populations of African origin, with higher BMI and greater sodium intake reported among American blacks compared to African blacks (3). Similar to BMI, sodium intake is a well-known factor influencing antihypertensive response to renin-angiotensin system antagonists (4–6). Thus, whether aldosterone antagonism would produce similar antihypertensive effects in black Americans compared to black Africans is uncertain.
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References
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- Flack JM, Oparil S, Pratt JH, et al. Efficacy and tolerability of eplerenone and losartan in hypertensive black and white patients. J Am Coll Cardiol. 2003;41:1148–1155[Abstract/Free Full Text]
- Lloyd-Jones DM, Evans JC, Larson MG, O'Donnell CJ, Roccella EJ, Levy D. Differential control of systolic and diastolic blood pressure: factors associated with lack of blood pressure control in the community. Hypertension. 2000;36:594–599[Abstract/Free Full Text]
- Cooper R, Rotimi C, Ataman S, et al. The prevalence of hypertension in seven populations of West African origin. Am J Public Health. 1997;87:160–168[Abstract/Free Full Text]
- Singer DR, Markandu ND, Cappuccio FP, Miller MA, Sagnella GA, MacGregor GA. Reduction of salt intake during converting enzyme inhibitor treatment compared with addition of a thiazide. Hypertension. 1995;25:1042–1044[Abstract/Free Full Text]
- Weir MR, Chrysant SG, McCarron DA, et al. Influence of race and dietary salt on the antihypertensive efficacy of an angiotensin-converting enzyme inhibitor or a calcium channel antagonist in salt-sensitive hypertensives. Hypertension. 1998;31:1088–1096[Abstract/Free Full Text]
- Houlihan CA, Allen TJ, Baxter AL, et al. A low-sodium diet potentiates the effects of losartan in type 2 diabetes. Diabetes Care. 2002;25:663–671[Abstract/Free Full Text]
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