Effect of race on hypertension and antihypertensive therapy

The presence of hypertension in individual patients confers significant risk in terms of coronary artery disease, myocardial infarction, stroke and congestive heart failure. However, it is also a modifiable risk factor, as risk may be decreased through either lifestyle changes or pharmacotherapy to reduce the elevated blood pressure. Over the past 3 decades, there has been strenuous debate among clinical scientists regarding the role played by racial background in both the pathogenesis and response to pharmacotherapy. A number of studies, such as the third National Health and Nutrition Examination Survey (NHANES III) have demonstrated a higher prevalence of hypertension in black populations. The Hispanic Health and Nutrition Examination Survey (HHANES) suggested that the prevalence of hypertension in Hispanics of Caribbean descent was similar to that of African Americans, while Mexican Americans had lower rates of the disease. It appears that the pathophysiological consequences of elevated blood pressure may also be more severe in black patients. Thus, these patients will have a worse prognosis than their white counterparts at any given blood pressure level. The incidence of end-stage renal disease has been reported to be as much as 17 times more common in African American patients. A number of individual factors have been postulated for these differences including increased sodium intake, differences in sodium handling, decreased potassium intake, decreased calcium intake, elevated fasting insulin levels, lower levels of plasma renin activity and urinary kallikrein excretion. These differences in prevalence and pathophysiology have resulted in recommendations for differential therapeutic approaches in the treatment of hypertension. A major trial conducted in the Veteran Affairs Medical Centers in the USA noted that African Americans are generally more responsive to diuretics and calcium channel blockers than to ACE inhibitors or beta-blockers. However, it has been reported that this resistance may be overcome by increasing the dose of these agents. It has been postulated that these differences may be related to lower plasma renin activity noted in the black population, since diuretics and calcium channel blockers appear to be better suited to this population. These differential therapeutic recommendations will be reviewed in light of our current knowledge of the disease.