Hypertension in Blacks

What is it about?

It is about the physiology of renal sodium handling, and how measuring plasma renin and aldosterone identifies the best therapy for patients with resistant hypertension. Black patients are more likely to have genetic causes of salt and water retention, due to inappropriate aldosterone secretion, and/or overactivity of the renal epithelial sodium channel (ENaC). Not only true Liddle syndrome (variants of SCNN1B (ENaC), but also variants of at least 5 other genes cause overactivity of ENaC, which is the chief determinant of salt and water retention. Patients with primary aldosteronism (usually due to bilateral hyperplasia) or inappropriate aldosterone secretion have a low renin/high aldosterone phenotype and are best treated with aldosterone antagonists. Those with a Liddle phenotype (low renin/low aldosterone) are best treated with amiloride, an antagonist of ENaC. Those with a renal phenotype (high renin/high aldosterone) are best treated with a renin inhibitor or angiotensin receptor blocker. Rarely, adrenalectomy or renal revascularization may be indicated.

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Why is it important?

African-Americans are more likely to have their hypertension detected, more likely to have it treated, and more likely to have it treated more intensively, but less likely to have it controlled. They have a much higher risk of stroke. To address this disparity it is important to individualize therapy. Physiological phenotyping with plasma renin and aldosterone markedly improved blood pressure control in black patients in Africa with uncontrolled hypertension.[1] This approach should be used also in African-Americans. 1. Akintunde A, Nondi J, Gogo K, Jones ESW, Rayner BL, Hackam DG, Spence JD. Physiological phenotyping for personalized therapy of uncontrolled hypertension in Africa. Am J Hypertens. 2017 Sep 1;30(9):923-930 PMID: 28472315