Primary aldosteronism is diagnosed with increasing frequency, especially between patients with hypertension. Thus, a reliable screening test is necessary to avoid costly and demanding diagnostic procedures to this population. The aim of the present study is the evaluation of aldosterone to renine ratio (A/R) in the diagnostic algorithm of patients with hypertension with or without adrenal insidentaloma.
A total of 115 subjects were studied: 13 patients with surgically proven hyperaldosteronism (Group I: age 50.5±1.4 yrs), 23 patients with adrenal incidentaloma (Group II: age 60.3±1.8 yrs, 11 hypertensive and 12 normotensive) and 79 subjects without known endocrinopathy (Group III: age 48.7±1.3 yrs, 27 hypertensive and 52 normotensive).
A ROC analysis was performed to define the A/R value that best discriminates patients with hyperaldosteronism. This analysis discloses that a A/R of 25 has a 100% sensitivity and A/R of 60 has a 100% specificity for primary hyperaldosteronism. A/R >25 was found in 1/11 hypertensive and in 2/12 non hypertensive patients of group II and in 4/27 hypertensive and in 2/52 non hypertensive subjects of group III. Patients of group II demonstrated significantly higher A/R than patients of group III (15.6±2 pg/ml and 9.88±0.9 pg/ml respectively P=0.002) and lower renin levels (16.68±3.2 μU/ml and 33.3±5.0 μU/ml respectively, P=0.001). No difference in A/R between hypertensive and normotensive individuals of groups II and III was found. Furthermore, patients of group II with subtle glucocorticoid hypersecretion demonstrated lower A/R compared to patients with normal cortisol secretion (11.7±2 vs 19.4±2.9, P=0.04).
Our results demonstrate that A/R is a reliable screening marker for the general population and for the patients with adrenal incidentalomas in order to exclude primary hyperaldosteronism. Furthermore, subtle aldosterone hypersecretion, as indicated by increased A/R, in patients with adrenal insidentalomas is not associated with the presence of hypertension or subtle glucocorticoid hypersecretion.
01 - 05 Apr 2006
European Society of Endocrinology