Evidences for mineralocorticoid excess in essential hypertension

Background: Primary hyperaldosteronism is more frequent among subjects with essential hypertension than previously thought. The prevalence, according to local and international evidence could fluctuate between 9 and 10%. Aim: To investigate if subjects with essential hypertension have different aldo sterone and renin plasma levels than normotensive subjects. Patients and me thods: One hundred twenty five subjects with essential hypertension, not re ceiving medications for a least two weeks prior to the study and 168 age an d sex matched normotensive controls were studied. Blood was drawn between 9 and 10 AM during a sodium free diet to determine plasma aldosterone, plasm a renin activity and potassium. Results: Plasma aldosterone was higher in h ypertensive subjects than controls (11.6 +/- 7.6 and 9.9 +/- 5.1 ng/dl resp ectively; p = 0.04). Plasma renin activity was lower in hypertensives than controls (1.42 +/- 1.28 and 1.88 +/- 1.39 ng/ml/h respectively; p < 0.001). Thus, plasma aldosterone/plasma renin activity ratio was higher in hyperte nsives (13.8 +/- 13.5 and 8.3 +/- 7.8; p < 0.001), A pathological ratio was defined as over 25, corresponding to the mean plus two standard deviations of the control group. Primary hyperaldosteronism was found in 5/125 hypert ensives (4%) and 1/168 normotensive subject (0.6%). None had hypokalemia. C onclusions: Subjects with essential hypertension have higher plasma aldoste rone and lower plasma renin activity than normal controls. A plasma aldoste rone/plasma renin activity over 25 was defined as abnormal.