Hypertension in Africa and effectiveness of its management with various classes of antihypertensive drugs and in different socio-economic and cultural environments

Abstract

Hypertension is the commonest cardiovascular disease in Africans occurring in more than 15% of the adult population in some studies. It occurs in the lower as much as in the higher socio-economic groups. Recent studies have confirmed earlier findings that essential hypertension in Africans is characterised by volume loading, low plasma renin activity, high salt taste threshold, high urinary sodium and low potassium excretion and high plasma aldosterone. The commonest complication of hypertension in Africans is congestive cardiac failure followed by cerebrovascular accidents. Coronary heart disease is rare. Even in the absence of overt heart failure and compounding factors like obesity, alcoholism, cigarette smoking, diabetes mellitus and myocarditis, evidence of abnormal left ventricular morphology and function is often present in newly diagnosed patients with moderate or severe hypertension. Response to monotherapy with beta-blockers or ACE inhibitors is usually poor but is good with thiazide diuretics or calcium channel blockers. The diuretics are an essential component of a two or three drug regime containing other classes of antihypertensive drugs. Cost of drugs is the most important determinant of compliance with drug treatment and consequently the likelihood of progression of the diseases to more severe forms in long term follow-up.