Impact of the Revised Aldosterone-Renin Ratio (ARR) Cutoff in the 2025 Primary Aldosteronism Guideline in Real-World Practice: A Prospective Study

Primary aldosteronism (PA) is one of the most common causes of secondary hypertension and is associated with an increased risk of cardiovascular, renal, and metabolic complications independent of blood pressure levels. Despite its clinical importance and the availability of effective targeted treatments such as adrenalectomy or mineralocorticoid receptor antagonists, PA remains substantially underdiagnosed in routine clinical practice, with estimates suggesting that only a small proportion of eligible hypertensive patients undergo appropriate screening.

The aldosterone-to-renin ratio (ARR) is the most widely used screening tool for PA. Traditionally, an ARR cutoff of >30 has been used to define a positive screening result. However, recent evidence suggests that this threshold may lack sufficient sensitivity and may miss a considerable number of patients with clinically relevant PA. In response, recent international hypertension and endocrine society guidelines have proposed lowering the ARR cutoff to >20 in order to improve case detection and broaden screening indications.

However, lowering the ARR threshold may also increase the number of false-positive results, potentially leading to an increased burden of aldosterone suppression test. Therefore, the clinical utility of the revised cutoff must be evaluated in real-world settings, particularly with regard to diagnostic yield and testing efficiency.

This study is a multicenter, prospective observational cohort study designed to evaluate the impact of applying the revised ARR cutoff (>20) in routine clinical practice in Korea. Patients with hypertension who meet predefined biochemical screening criteria indicating an intermediate probability of lateralizing PA will be enrolled.

Participants will undergo standardized pre-analytical preparation, including medication adjustment and controlled sampling conditions. All eligible participants will undergo confirmatory testing using the saline infusion test (SIT), performed under standardized protocols (supine or seated depending on institutional practice).