IN PRIMARY ALDOSTERONISM THE CIRCADIAN BLOOD-PRESSURE RHYTHM IS SIMILAR TO THAT IN PRIMARY HYPERTENSION

To investigate whether the 24-hour blood pressure (BP) profile of prim ary aldosteronism differs from that of primary hypertension, ambulator y BP monitoring was performed in 11 patients with primary aldosteronis m (9 with an adrenal adenoma and 2 with idiopathic hyperaldosteronism) and in 11 primary hypertensives, matched for sex (5M,6F), age (mean: 52 vs 49 yrs) and casual BP. We found no difference in 24-hour BP, noc turnal BP fall, BP variability (standard deviation and peaks of pressu re) response to postural changes (lying-standing BP) between the two g roups (all p values n.s.). Within the patients with primary aldosteron ism no correlation was observed between BP, plasma renin activity, blo od and urine aldosterone levels, blood and urine K+ and size of the tu mour. Thus, at variance with previous reports, these results show that diurnal rhythm of BP and BP variability are similar in primary aldost eronism and primary hypertensives with similar demographic features an d casual BP levels. They also show that an orthostatic fall of BP is n ot a common feature in this disease.