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Electronic letters published:
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ACE inhibition in black patients
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Jay S Kaufman, PhD Department of Epidemiology, UNC School of Public Health, John M. Flack, M.D., M.P.H
Send rapid response to journal:
Jay_Kaufman{at}unc.edu Jay S Kaufman, et al.
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We read with interest the review article by Brewster and colleagues in which they summarized effects on blood pressure and blood pressure control of single antihypertensive agents reported in clinical studies that enrolled black patients in both the Americas and Africa. They highlight the observation that for ACE inhibitors the summary effect on diastolic control (as a binary outcome) did not differ significantly from placebo. However they also found that for these agents, changes in both systolic (-7.43 mmHg) and diastolic pressure (-3.35 mmHg) were each significantly greater than for placebo. The finding that the effect of ACE inhibition was non-significant in relation to placebo was based on only three studies, two of which enrolled participants with baseline DBP greater than or equal to 110 mmHg. Moreover, these two studies apparently used “per protocol analysis” (as opposed to intention-to-treat), and when only intention-to- treat analyses were considered the effect of ACE inhibition on DBP control was significantly greater than for placebo (RR = 1.74, 95% CI: 1.04, 2.92). An additional concern is that participants on multiple antihypertensive medications with poorly controlled blood pressure were allowed in these trials and subsequently treated with a single drug regimen, a scenario that likely attenuated the in-trial response. Blood pressure response distributions to ACE inhibitors overlap considerably between black and white populations. (1,2) That some antihypertensive therapies have reliably distinct effects in comparable black and white populations is an unlikely premise, and is also challenging because of the even greater social and genetic heterogeneity in black populations. For example, most of the genetic variability in the human species occurs within African-origin populations (3), and most genetic and social heterogeneity is within racial groups, not between them. The most sensible null hypothesis from which to work in any study of drug effects is that of homogeneity of effects across continental populations. When there is evidence of significant effect measure heterogeneity, then this null hypothesis may be rejected and the search for biological or social explanations may commence. However this present meta-analysis should not be over-interpreted as providing evidence for such differential treatment effects that merit differential prescribing patterns by race. Jay S. Kaufman, Ph.D. John M. Flack, M.D., M.P.H 1. Mokwe E, Ohmit SE, Nasser SA, Shafi T, Saunders E, Crook E, Dudley A, Flack JM. Determinants of blood pressure response to quinapril in black and white hypertensive patients: the Quinapril Titration Interval Management Evaluation trial. Hypertension. 2004 Jun;43(6):1202-7. 2. Sehgal AR. Overlap between whites and blacks in response to antihypertensive drugs. Hypertension. 2004 Mar;43(3):566-72. 3. Gabriel SB, Schaffner SF, Nguyen H, Moore JM, Roy J, Blumenstiel B, Higgins J, DeFelice M, Lochner A, Faggart M, Liu-Cordero SN, Rotimi C, Adeyemo A, Cooper R, Ward R, Lander ES, Daly MJ, Altshuler D. The structure of haplotype blocks in the human genome. Science. 2002 Jun 21;296(5576):2225-9. Conflict of Interest:None declared |
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