5042 The Prevalence of Primary Aldosteronism in Incidentally Discovered Adrenocortical Adenomas Irrespective of Blood Pressure: A Prospective Cohort Study

Abstract Disclosure: T. Uslar: None. A. Burnier: None. B. Sanfuentes: None. P. Böhm: None. M. Orellana: None. F.J. Guarda: None. R.I. Olmos: None. Á. Huete: None. N. Mertens: None. C. Besa: None. A. Majerson: None. J. Cartes: None. C.E. Fardella: None. F. Allende: None. S. Solari: None. A. Vaidya: Consulting Fee; Self; Corcept Therapeutics, HRA Pharmaceuticals. R. Baudrand: None. Background: Incidental adrenocortical adenomas are commonly found on imaging. Guidelines recommend screening for primary aldosteronism (PA) only when adrenocortical adenomas are accompanied by hypertension or unexplained hypokalemia. Objective: To prospectively evaluate the prevalence of PA in consecutive patients with incidentally discovered adrenocortical adenomas. Design: Prospective, longitudinal, single-center study. Methods: 254 consecutive patients with incidentally discovered adrenocortical adenomas were studied, without any evidence of autonomous cortisol secretion, excluded via 1mg dexamethasone suppression test. A structured protocol was followed, which involved measurement of plasma aldosterone (PAC), 24h-urinary aldosterone and sodium, plasma renin activity (PRA) and/or direct renin (DRC). Samples were collected in the morning, in a seated posture, after withdrawing interfering medications. Possible PA was defined across a continuum by having a low renin (DRC <10 uIU/mL or PRA < 1ng/mL/hr) in addition to one of the following 3 criteria reflecting the severity of PA: 1) overt PA: aldosterone/renin ratio (ARR) >30, PA >15 ng/dL, and/or 24h urinary aldosterone >10 ug/24h; 2) moderate PA: ARR 20-30 and PAC 10-15 ng/dL; 3) mild PA: ARR <20 and PAC 5-10ng/dL. Adjusted linear regressions were performed. Patients were followed longitudinally to evaluate treatment outcomes with paired T-test. Results: Among patients with incidentally discovered adrenocortical adenomas, 35% (n=89/254) had possible PA. Overt, moderate, and mild PA were identified in 10%, 12%, and 13% of the overall sample, respectively. Notably, one in five of these individuals (20%) were normotensive. There were trends across the 3 phenotypes of PA indicating a continuum of severity, including: systolic blood pressure (152 ±19, 144 ±13, 142 ±16 mmHg, p-trend=0.02), resistant hypertension (56%, 38%, 33% p-trend=0.034), daily defined dose of antihypertensives (DDD) (2.9 ±1.8, 2.1 ±1.5, 1.0 ±0.8 p-trend=0.001), higher PAC (30.7 ±29.4, 10.3 ± 2.7, 7.9 ±2.5ng/dL p-trend<0.001) and urinary aldosterone (18.2 ±12, 5.6 ±3.6, 5.5 ±3.9 ug/24h p-trend<0.001). In longitudinal treatment follow-up (mean 28-months), 83% had a favorable response to treatment (84% medical, 16% adrenalectomy). After treatment, there was a decrease in SBP of -31.3 ±23 mmHg in overt PA, -13.2 ±19 mmHg in moderate PA, and -9.4 ±18 mmHg in mild PA (p<0.001 in all groups). Similar trends were observed for DDD, with a significant increase in renin in all groups. Conclusions: Overt PA, as well as a continuum of PA, was frequently seen in up to 35% of incidentally discovered adrenocortical adenomas. These findings underscore the importance of screening for PA in all patients with adrenocortical adenomas, irrespective of blood pressure and/or hypokalemia. Presentation: 6/1/2024