Context: Primary aldosteronism (PA) is an established cause of hypertension, whereas high-normal serum aldosterone levels have been linked to an increased risk for hypertension.
Objective: We aimed to define the post-fludrocortisone-dexamethasone suppression test (FDST) normal cutoff values of aldosterone and the aldosterone to renin ratio and evaluate the presence of PA in normotensive individuals.
Design: This study was designed as a case-control study.
Setting: The study was performed in a tertiary general hospital.
Patients: One hundred normotensive participants (80 females), mean age 53 years, were studied.
Main outcome measures: All participants underwent baseline biochemical and hormonal evaluation, FDST, and adrenal computerized tomography. Blood pressure was assessed at baseline and after 5 years.
Results: Sixty-nine participants with normal adrenal computerized tomography who remained normotensive after 5 years were used as a control population to calculate the cutoff values of adequate aldosterone suppression. PA was defined as a combination of post-FDST aldosterone to renin ratio of 0.93 ng/dL · μU/mL or greater (100% sensitivity and 96% specificity) and post-FDST aldosterone of 2.96 ng/dL or greater (100% sensitivity and 61% specificity on receiver-operating characteristic analysis). Thirteen of 100 participants had PA at baseline and 11 (85%) developed hypertension, whereas only 20 of 87 without PA (23%) developed hypertension at 5 years [odds ratio (OR) 18.42, 95% confidence intervals (CI) 3.76-90.10, P < .0001]. Logistic regression analysis showed a positive relation of PA [odds ratio (OR) 16.30, confidence interval (CI) 1.78-150.30, P = .01] and a negative relation of serum potassium (OR 0.39, CI 0.19-0.79, P = .01) with the development of hypertension.
Conclusions: Normotensive PA represents a clinical entity referring to normotensive individuals with PA who are at increased risk for hypertension.