Aldosterone to Potassium Ratio after Adrenocorticotropin Stimulation in Unilateral Primary Aldosteronism Diagnosis

抄録

Background : It is important to identify patients with primary aldosteronism (PA) who have a high possibility of having aldosterone-producing adenoma (APA). However, the usefulness of the adrenocorticotropic hormone (ACTH) stimulation test for such purposes is controversial. This study aimed to evaluate the diagnostic accuracy of the ACTH stimulation test, corrected for serum potassium concentration, in the identification of unilateral lesion among patients with PA.
Methods : Seventy-nine patients with PA admitted to three medical centers were included in the study. ACTH stimulation tests and saline infusion tests (SITs) were performed. Plasma aldosterone concentration (PAC) was examined at 0, 30, and 60 min following ACTH stimulation and at 240 min following SIT. Receiver operator characteristic curve analysis was used to evaluate the diagnostic accuracy. Medical records were reviewed retrospectively.
Results : The area under the curve (AUC) at 240 min following SIT was 0.920, and the optimal cut-off value was 133.7pg/mL, with a sensitivity of 92.3％ and a specificity of 93.1％. For the ACTH stimulation test, the AUCs for the PAC-to-potassium concentration ratio at 0, 30, and 60 min were 0.979, 0.984, and 0.971, respectively. The most effective parameter for predicting unilateral lesion suggesting APA was the PAC-to-potassium concentration ratio at 30 min, with a sensitivity of 100％ and a specificity of 95.5％.
Conclusion : These results show that the PAC-to-potassium concentration ratio at 30 min in the ACTH stimulation test, as well as the PAC at 240 min in the SIT, is an excellent and practical indicator for identifying unilateral lesion in patients with PA.