Comparison of 24-h urinary aldosterone level and random urinary aldosterone-to-creatinine ratio in the diagnosis of primary aldosteronism

• Published in: PloS one Vol. 8; no. 6; p. e67417
• Main Authors: Wu, Che-Hsiung, Yang, Ya-Wen, Hu, Ya-Hui, Tsai, Yao-Chou, Kuo, Ko-Lin, Lin, Yen-Hung, Hung, Szu-Chun, Wu, Vin-Cent, Wu, Kwan-Dun
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28.06.2013; Public Library of Science (PLoS)
• Subjects: Adenoma; Adenoma - complications; Adenoma - urine; Adrenal Gland Neoplasms - complications; Adrenal Gland Neoplasms - urine; Adrenal glands; Adult; Aldosterone; Aldosterone - urine; Biology; Bladder; Buddhism; Chemistry; Creatinine; Creatinine - urine; Diagnosis; Diagnostic software; Diagnostic systems; Endocrine disorders; Essential Hypertension; Female; Historical account; Hospitals; Humans; Hyperaldosteronism - diagnosis; Hyperaldosteronism - etiology; Hyperaldosteronism - urine; Hypertension; Hypertension - urine; Hypokalemia; Internal medicine; Kinases; Male; Medical diagnosis; Medical imaging; Medicine; Metabolism; Middle Aged; Nephrology; Patients; Plasma; Potassium; Prospective Studies; Restoration; ROC Curve; Salt loading; Salts; Sodium; Studies; Surgery; Tomography; Tumors; Urinary bladder; Urine; Taiwan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0067417

Historically, urinary aldosterone level measurement was a commonly employed confirmatory test to detect primary aldosteronism (PA). However, 24-h urine collection is inconvenient and cumbersome. We hypothesized that random urinary aldosterone measurements with correction for creatinine concentration might be comparable to 24-h urinary aldosterone levels (Uald-24 h) in the diagnosis of PA. The non-concurrent prospective study was conducted between June 2006 and March 2008 in patients admitted for confirmation of aldosteronism by salt loading test. A 24-h urine sample, which was collected during hospitalization on the day before saline infusion testing after restoration of serum hypokalemia, was collected from all subjects. Moreover, participants were asked to collect a first bladder voiding random urine sample during clinic visits. Uald-24 h and the random urinary aldosterone-to-creatinine ratio (UACR) were calculated accordingly. A total of 102 PA patients (71 patients diagnosed of aldosterone-producing adenoma, 31 with idiopathic hyperaldosteronism) and 65 patients with EH were enrolled. The receiver operating characteristic curve showed comparable areas under the curves of UACR and Uald-24 h. The Bland-Altman plot showed mean bias but no obvious heteroscedasticity between the two tests. When using random UACR >3.0 ng/mg creatinine as the cutoff value, we obtained a specificity of 90.6% to confirm PA from essential hypertension. Our study reinforce that the diagnostic accuracy of random UACR was comparable to that of Uald-24 h in PA patients. With the quickness and simplicity of the UACR method and its equivalence to Uald-24 h, this assay could be a good alternative diagnostic tool for PA confirmation.