ORF31-08 - Real-World Applicability of the 2025 Endocrine Society Guidelines for Primary Aldosteronism for Patients in Thailand

Background: The 2025 Endocrine Society (ES) guidelines for primary aldosteronism (PA) propose new approaches for screening, new methods for predicting PA subtypes, and new indications for using confirmatory testing to predict adrenal venous sampling (AVS) outcomes.

Objective: To assess the applicability and diagnostic performance of the updated 2025 ES guidelines in a large cohort of Thai patients with PA.

Methods: This retrospective study included 227 patients diagnosed with PA at Phramongkutklao Hospital, Bangkok, Thailand from June 2015 to October 2025. All patients with PA were diagnosed using the 2016 ES guidelines and further affirmed with subsequent AVS and/or biochemical or clinical improvement following unilateral adrenalectomy or mineralocorticoid receptor antagonist therapy. Three complementary analyses were conducted to evaluate the performance of 2025 ES guideline recommendations for 1) screening; 2) subtype prediction based on renin, aldosterone, and potassium values; and 3) confirmatory testing-based subtype prediction.

Results: The updated 2025 ES screening criteria demonstrated high concordance for detecting PA (94.7-97.4%) with the 2016 reference criteria. In contrast, the prediction of subtype based on renin, aldosterone, and potassium measurements, as newly proposed in the 2025 ES guidelines, performed poorly. The true discovery rate of unilateral PA among those predicted to have a “low”, “intermediate”, and “high” probability of lateralizing PA was 80% (4/5), 63% (109/173), and 79.6% (39/49), respectively, indicating a high rate of lateralizing PA regardless of probability stratifications. Furthermore, the use of the seated saline suppression test to predict lateralizing PA, as newly proposed in the 2025 ES guidelines, also did not provide high discriminatory value for lateralization; 91.9% of those with unilateral PA and 85.3% of those with bilateral PA had a positive saline suppression test, a finding that persisted among patients designated as “intermediate” probability of lateralizing PA for whom the 2025 ES guidelines recommend confirmatory testing to guide subtyping (96.2% and 84.4%, respectively). The use of confirmatory testing for predicting lateralizing PA among those labeled “intermediate” probability showed an overall accuracy of only 65.9%, primarily driven by low specificity (15.6%) and suboptimal negative predictive value (71.4%).

Conclusion: The updated 2025 ES guidelines for PA screening demonstrated very good performance in detecting PA in Thai patients. In contrast, the new ES recommendation to predict subtype, with either measurements obtained during screening or confirmatory testing, lack discriminatory power. Thai clinicians evaluating PA should consider these caveats when applying the 2025 ES guidelines to their practice.

Keywords: Primary aldosteronism; Saline suppression test; Lateralizing; Thailand