Determination of the Aldosterone/Renin Ratio in 269 Patients with Adrenal Incidentaloma

To determine the prevalence of primary aldosteronism among patients with incidentally discovered adrenal adenomas ('incidentalomas') plasma concentrations of aldosterone (PA) and plasma renin activity (PRA) were determined in 269 patients (100 normotensives, 169 hypertensives) newly referred incidentaloma patients. Among the 100 normotensives a PA [ng/dl]/PRA [ng/ml.h]-ratio (A/R-R) >50 and a concomitant elevation of PA (>15 pg/ml) was initially seen in two cases but further investigations excluded the presence of primary aldosteronism in both patients suggesting a prevalence of primary aldosteronism of <1% among normotensive patients with adrenal incidentaloma. Among the 169 hypertensive incidentaloma patients 14 presented with both, an elevated PA [>15 pg/ml] and an A/R-R >50. Primary aldosteronism was confirmed in 6 of this cases resulting in a prevalence of primary aldosteronism among hypertensive incidentaloma patients of 4%. Although obtained in patients with a supposedly high pre-test probability of primary aldosteronism this percentage--while in keeping with the older literature--is surprisingly low given the recently reported large(r) prevalence of primary aldosteronism among hypertensives in general.