Elias Paula C L, Martinez Edson Z, Barone Bruno F C, Mermejo Livia M, Castro Margaret, Moreira Ayrton C
Division of Endocrinology Department of Medicine (P.C.L.E., B.F.C.B., L.M.M., M.C., A.C.M.) and Division of Statistics Department of Social Medicine (E.Z.M.), Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Sao Paulo 14049-900, Brazil.
J Clin Endocrinol Metab. 2014 Jun;99(6):2045-51. doi: 10.1210/jc.2013-4262. Epub 2014 Mar 14.
The comparison of variability, reproducibility, and diagnostic performance of late-night salivary cortisol (LNSF) and urinary free cortisol (UFC) using concurrent and consecutive samples in Cushing's syndrome (CS) is lacking. Objectives, Patients, and Methods: In a prospective study, we evaluated 3 simultaneous and consecutive samples of LNSF by RIA and UFC by liquid chromatography associated with tandem mass spectrometry in Cushing's disease (CD) patients (n = 43), adrenal CS patients (n = 9), and obese subjects (n = 18) to compare their diagnostic performances. In CS patients, we also performed a modified CS severity index.
There was no difference in the coefficient of variation (percentage) between LNSF and UFC among the 3 samples obtained for each patient with Cushing's disease (35 ± 26 vs 31 ± 24), adrenal CS (28 ± 14 vs 22 ± 14), and obesity (39 ± 37 vs 48 ± 20). LNSF confirmed the diagnosis of hypercortisolism even in the presence of normal UFC in 17.3% of CS, whereas the inverse situation was not observed for UFC. The area under the receiver-operating characteristic curves for LNSF was 0.999 (95% credible interval [CI] 0.990-1.00) and for UFC was 0.928 (95% CI 0.809-0.987). The ratio between areas under the curve was 0.928 (95% CI 0.810-0.988), indicating better performance of LNSF than UFC in diagnosing CS. There was no association between the CS severity index and the degree of biochemical hypercortisolism.
Our data show that despite similar variability between both methods, LNSF has a superior diagnostic performance than UFC and should be used as the primary biochemical diagnostic test for CS diagnosis.
缺乏在库欣综合征（CS）中使用同步和连续样本对午夜唾液皮质醇（LNSF）和尿游离皮质醇（UFC）的变异性、可重复性和诊断性能进行比较的研究。目的、患者和方法：在一项前瞻性研究中，我们通过放射免疫分析法（RIA）评估了43例库欣病（CD）患者、9例肾上腺CS患者和18例肥胖受试者的3份同步且连续的LNSF样本，并通过液相色谱串联质谱法评估了UFC样本，以比较它们的诊断性能。在CS患者中，我们还进行了改良的CS严重程度指数评估。
在为每位库欣病患者、肾上腺CS患者和肥胖受试者获取的3份样本中，LNSF和UFC之间的变异系数（百分比）没有差异（分别为35±26 vs 31±24、28±14 vs 22±14、39±37 vs 48±20）。在17.3%的CS患者中，即使UFC正常，LNSF也能确诊皮质醇增多症，而UFC未观察到相反情况。LNSF的受试者工作特征曲线下面积为0.999（95%可信区间[CI] 0.990 - 1.00），UFC为0.928（95% CI 0.809 -
