Prevalence of Primary Aldosteronism Across the Stages of Hypertension Based on a New Combined Overnight Test.

Primary aldosteronism (PA) is the most common endocrine cause of arterial hypertension. Despite the increasing incidence of hypertension worldwide, the true prevalence of PA in hypertension was only recently recognized. The objective of the work was to estimate the prevalence of PA in patients at different stages of hypertension based on a newly developed screening-diagnostic overnight test. This is a prospective study with hypertensive patients (n=265) at stage I (n=100), II (n=88), and III (n=77) of hypertension. A group of 103 patients with essential hypertension without PA was used as controls. PA diagnosis was based on a combined screening-diagnostic overnight test, the Dexamethasone-Captopril-Valsartan Test (DCVT) that evaluates aldosterone secretion after pharmaceutical blockade of angiotensin-II and adrenocorticotropic hormone. DCVT was performed in all participants independently of the basal aldosterone to renin ratio (ARR). The calculated upper normal limits for post-DCVT aldosterone levels [3 ng/dl (85 pmol/l)] and post-DCVT ARR [0.32 ng/dl/µU/ml (9 pmol/IU)] from controls, were applied together to establish PA diagnosis. Using these criteria PA was confirmed in 80 of 265 (30%) hypertensives. The prevalence of PA was: 21% (21/100) in stage I, 33% (29/88) in stage II, and 39% (30/77) in stage III. Serum K+ levels were negatively correlated and urinary K+ was positively correlated in PA patients with post-DCVT ARR (r=-0.349, p <0.01, and r=0.27, p <0.05 respectively). In conclusion, DCVT revealed that PA is a highly prevalent cause of hypertension. DCVT could be employed as a diagnostic tool in all subjects with arterial hypertension of unknown cause.

Enhanced performance of a modified diagnostic test of primary aldosteronism in patients with adrenal adenomas.

OBJECTIVE: Primary aldosteronism (PA) is the commonest cause of endocrine hypertension ranging from 4.6 to 16.6% according to the diagnostic tests employed. The aim of this study was to compare the traditional saline infusion test (SIT) with the modified post-dexamethasone saline infusion test (DSIT) by applying both tests on the same subjects. METHODS: We studied 68 patients (72% hypertensives) with single adrenal adenoma and 55 normotensive controls with normal adrenal imaging. Serum cortisol, aldosterone, and plasma renin concentration (PRC) were measured and the aldosterone-to-renin ratio (ARR) was calculated. Using the mean ± 2 s.d. values from the controls, we defined the upper normal limits for cortisol, aldosterone, and PRC for both the SIT and DSIT. RESULTS: In the controls, the post-DSIT aldosterone levels and the ARR were approximately two-fold and three-fold lower, respectively, than the corresponding post-SIT values (all P = 0.001) leading to lower cut-offs of aldosterone suppression. Applying these cut-offs to patients with adrenal adenomas, the prevalence of PA was 13.2% following the SIT and 29.4% following the DSIT, respectively. In addition, 54.5% of patients with PA had concomitant autonomous cortisol secretion (ACS). Targeted treatment of PA resulted in resolution of hypertension and restoration of normal secretory aldosterone dynamics. CONCLUSIONS: The DSIT improves the diagnostic accuracy of PA, allowing for the detection of milder forms of PA in patients with adrenal adenomas. This is of particular importance as such patients may be at an increased risk of developing cardiovascular and renal morbidity that could be enhanced in the presence of concomitant ACS.

High Prevalence of Primary Aldosteronism in Patients with Type 2 Diabetes Mellitus and Hypertension.

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. The prevalence of hypertension is higher in patients with diabetes mellitus-2 (DM-2). Following the limited existing data, we prospectively investigated the prevalence of aldosterone excess either as autonomous secretion (PA) or as a hyper-response to stress in hypertensive patients with DM-2 (HDM-2). A total of 137 HDM-2 patients and 61 non-diabetics with essential hypertension who served as controls (EH-C) underwent a combined, overnight diagnostic test, the Dexamethasone-captopril-valsartan test (DCVT) used for the diagnosis of PA and an ultralow dose (0.3 µg) ACTH stimulation test to identify an exaggerated aldosterone response to ACTH stimulation. Twenty-three normotensive individuals served as controls (NC) to define the normal response of aldosterone (ALD) and aldosterone-to-renin ratio (ARR) to the ultralow dose ACTH test. Using post-DCVTALD and ARR from the EH-C, and post-ACTH peak ALD and ARR from the NC, 47 (34.3%) HDM-2 patients were found to have PA, whereas 6 (10.4%) HDM-2 patients without PA (DCVT-negative) exhibited an exaggerated aldosterone response to stress-a prevalence much higher than ever reported. Treatment with mineralocorticoid receptor antagonists (MRAs) induced a significant and permanent reduction of BP in all HDM-2 patients. Early diagnosis and targeted treatment of PA is crucial to prevent any aggravating effect on chronic diabetic complications.