Study on Cutoff Revision Effects and Evaluation of NNT in Primary Aldosteronism

The goal of this observational study is to evaluate the real-world impact of applying the revised aldosterone-to-renin ratio (ARR) cutoff recommended in the 2025 primary aldosteronism guideline in adults with hypertension and biochemical findings suggestive of an intermediate probability of lateralizing primary aldosteronism (PA). The main questions it aims to answer are: * What is the number needed to test (NNT) to diagnose one case of primary aldosteronism when using the revised ARR cutoff (\>20)? * What is the optimal ARR cutoff for diagnosing PA in Korean patients? * What is the biochemical treatment response rate at 6 months after treatment for confirmed PA? Participants will: * Undergo standardized ARR testing after protocol-based medication adjustment and controlled sampling conditions. * Undergo confirmatory testing using the saline infusion test (SIT). * Receive standard clinical management for confirmed PA according to institutional practice. * Be followed for assessment of biochemical outcomes after treatment.