Primary aldosteronism in hypertensive patients: clinical implications and target therapy

BACKGROUND: The prevalence of primary aldosteronism (PA) in hypertensive patients varies according to diagnostic testing and ascertained normal cut-offs. The aim of this case-control study was to confirm the high prevalence of PA in a large hypertensive population and evaluate the antihypertensive effect of mineralocorticoid receptor antagonists (MRA) treatment. MATERIAL AND METHODS: We investigated 327 hypertensive and 90 matched normotensive subjects with normal adrenal imaging. Serum aldosterone (ALD), active renin (REN) levels and aldosterone/active renin (ALD/REN) ratio were measured before and after a combined sodium chloride, fludrocortisone and dexamethasone suppression test (FDST). Post-FDST values were compared to cut-offs obtained from controls (post-FDST ALD 2·96 ng/dL and post-FDST ALD/REN 0·93 ng/dL/μU/mL). PA patients received MRA treatment. RESULTS: By applying the combination of post-FDST ALD levels and ALD/REN ratio, 28·7% of the hypertensive patients had PA. There was a positive, albeit weak, correlation between systolic (SBP) and diastolic blood pressure (DBP) and ALD levels and/or ALD/REN ratio after the FDST (P < 0·0001). SBP was associated with a post-FDST ALD of 3·24 ng/dL and ALD/REN ratio of 0·90 ng/dL/μU/mL, whereas post-FDST ALD had an inverse association at serum K+ values of less than 3·9 mEq/L. MRA treatment in 69 PA patients, resulted in a significant reduction in the maximum SBP and DBP values (28 ± 15 and 14 ± 7 mmHg, respectively, P < 0·0001). CONCLUSIONS: Using the FDST, an increased prevalence of PA in hypertensives was observed. Α significant blood pressure lowering effect was obtained with MRA treatment, implying that these agents may be beneficial in a significant number of hypertensive patients.