Clinical Characteristics and Treatment Outcomes of Primary Aldosteronism in a Tertiary Hospital in Thailand

Background: Primary aldosteronism (PA) is the most common cause of endocrine hypertension, increasing cardiovascular and renal risks. This study aimed to provide comprehensive information on PA patients in Thailand, where data are limited. Materials and A retrospective study of 127 PA patients during 2012 to 2023 from Thammasat University Methods: Hospital was conducted. Data on clinical and biochemical parameters, screening, confirmatory testing, subtype classification, and treatment outcomes were evaluated. Results: Fifty patients (39%) had unilateral PA, 50 (39%) bilateral PA, and 27 (21%) were classified as inconclusive subtype. Mean age was 54 years, and 54% were female. All participants had hypertension, with 10% having resistant hypertension. Eighty-three percent had hypokalemia. Median plasma aldosterone concentration (PAC), direct renin concentration (DRC), and PAC/DRC ratio (ADRR) were 21.7 ng/dL, 3.7 μIU/mL, and 5.3 ng/dL: μIU/mL, respectively. The recumbent saline infusion test (RSIT) was the most common confirmatory test, with a 66% positive rate. Adrenal CT scan was performed in all cases. Ninety-two percent of patients underwent adrenal venous sampling, with a 78% success rate. Among adrenal ectomy patients, 53% achieved complete clinical success and 94% achieved biochemical success. Unilateral PA showed higher PAC, ADRR, PAC-potassium ratio, and lower DRC. Conclusions: Comprehensive PA data supports accurate diagnosis and tailored treatment. Hypokalemia is common in Thai PA patients. Unilateral PA shows a severe phenotype with distinctive hormonal profiles. For confirmatory testing, RSIT is reliable and SSIT promising. AVS, superior to CT for subtyping, is crucial for accurate subtype classification, as nearly all unilateral PA patients achieve complete biochemical remission post-adrenalectomy.