Appraisal of Modified Tests for Diagnosis and Treatment of Primary Aldosteronism: A Single Center Experience

Introduction: Primary aldosteronism (PA), the most common endocrine cause of secondary hypertension, is generally under diagnosed using current diagnostic tests. Objective: To present our findings, based on studies using modified diagnostic tests, on the diagnosis, prevalence and treatment of PA. Design and Methods: We prospectively studied 992 hypertensive patients and 278 matched controls. Participants underwent conventional confirmatory tests for the diagnosis of PA modified by the addition of dexamethasone including the Fludrocortisone Dexamethasone Suppression Test (FDST), the Dexamethasone Captopril Valsartan Test (DCVT) and the Dexamethasone Saline Infusion Test (DSIT). Normal cut-offs of basal aldosterone-to-renin ratio and post-test (FDST, DCVT and DSIT) aldosterone levels and aldosterone-to-renin ratio were calculated from the control groups, who had normal adrenal imaging. Results: Hypertensive patients had significantly higher baseline blood pressure and lower serum potassium levels compared to controls. Using the basal aldosterone-to-renin ratio as screening test, the prevalence of PA was 17.8%. After applying the modified tests to all patients, the prevalence of PA was 33.4%. Targeted treatment with Mineralocorticoid Receptor Antagonists was administered in 252 hypertensives, with bilateral PA; 188 (74.6%) of them obtained a biochemical response and normalization of blood pressure. Unilateral disease had 48 patients who underwent laparoscopic adrenalectomy obtaining a biochemical success rate was 94%. Conclusion: Our modified methodology and the use of normotensive controls for calculation of normal cut-offs of aldosterone suppression, significantly improves the sensitivity and specificity of the existing tests on the diagnosis of PA, allowing the detection of milder forms.