Assessing Primary Aldosteronism Screening Implementation and Interpretation in an Outpatient Internal Medicine Clinic: A Cohort Study.

Background/Objective: Primary aldosteronism (PA) is associated with increased cardiovascular risk and accounts for up to 30% of resistant hypertension cases, but less than 2% of true PA cases are diagnosed. The aldosterone-to-renin ratio (ARR) is the most common screening tool but is often misinterpreted due to failure to assess aldosterone and renin separately. Appropriate screening should be conducted off mineralocorticoid antagonists and serum potassium should be within normal limits on the day of testing. The aim of this study was to determine rates of appropriate PA screening and management in primary care. Methods: Adults newly established between 2021 and 2024 with indications for PA screening including resistant hypertension, hypertension on ≥4 medications or 3 medications with blood pressure > 130/80 mmHg, or hypertension with atrial fibrillation, adrenal adenoma, or hypokalemia were included. We assessed whether patients underwent renin and aldosterone testing, if testing occurred under appropriate conditions, and whether results were interpreted correctly. Results: A total of 312 patients were indicated for PA screening primarily due to being on 3 antihypertensives with uncontrolled blood pressure (35.3%) or ≥4 antihypertensives (42.9%). Twelve patients (3.8%) were screened for PA, and 5 (41.7%) of those patients were screened appropriately. All screenings were interpreted as negative, yet 4 patients had true positive results. This study was limited to new patient encounters within a single internal medicine clinic and only followed patients for up to 12 months. Conclusion: PA remains underdiagnosed and mismanaged in primary care. Findings highlight the need for better provider education, awareness, and standardized protocols to improve detection and treatment for PA.