Objective: To evaluate the efficacy of 24 h urinary free cortisol (24 h UFC) in the diagnosis of subclinical Cushing's syndrome (SCS), and explore the best diagnostic cut-off value. Methods: The clinical data of patients with adrenal incidentaloma in Chinese PLA General Hospital between January 2008 and December 2016 was retrospectively reviewed and analyzed. All SCS patients were diagnosed based on the current Cushing's syndrome (CS) guidelines and confirmed by histopathology and then treated as study group, and additional patients with non-functional adrenal adenoma (NFA) were enrolled as control group. ROC curve was used to evaluate efficacy of 24 h UFC and 24 h UFC to creatinine ratio (UFCCR), and explore their best cut-off values. Results: There were 161 patients with NFA, of which contained 84 males and 77 females, with a mean age of (51.02±10.49) years old. There were 88 patients with SCS, of which contained 26 males and 62 females, with a mean age of (51.74±10.29) years old. The 24 h UFC and UFCCR levels were significant higher in SCS group than those in NFA group[510 (363, 698) nmol vs 335 (209, 467) nmol for 24 h UFC, and 7.82(4.79, 12.13) ml vs 4.82(2.41, 6.57)ml for UFCCR, both P<0.05]. ROC analysis showed that the optimal cut-off for 24 h UFC was 480 nmol (AUC 0.716, 95% CI: 0.648-0.784, with a sensitivity of 58.0% and a specificity of 79.4%) and the optimal cut-off for UFCCR was 6.84 ml (AUC 0.729, 95% CI: 0.662-0.796, with a sensitivity of 59.1% and a specificity of 78.7%). Conclusions: The recommended cut-off points of 24 h UFC and UFCCR for diagnosing SCS in AI patients were 480 nmol and 6.84 ml, respectively.
目的： 探讨24 h尿游离皮质醇(24 h UFC)对肾上腺意外瘤(AI)中亚临床库欣综合征(SCS)的诊断价值和最佳诊断切点。 方法： 回顾性分析2008年1月—2016年12月在解放军总医院内分泌科住院诊治的AI患者的病例资料，以目前国内外指南推荐的库欣综合征(CS)诊断标准＋术后病理证实为金标准，SCS为试验组，肾上腺无功能腺瘤(NFA)为对照组，采用ROC曲线对24 h UFC以及24 h UFC/血清肌酐比值(UFCCR)对SCS的诊断价值进行评价并找出最佳切点。 结果： 共纳入SCS患者88例，其中男26例，女62例，就诊年龄(51.02±10.49)岁；NFA患者161例，其中男84例，女77例，就诊年龄(51.74±10.29)岁。SCS组24 h UFC、UFCCR均显著高于NFA组，分别为510(363，698)nmol比335(209，467)nmol和7.82(4.79，12.13)ml比4.82(2.41，6.57)ml，均P<0.05。24 h UFC为诊断指标的曲线下面积为0.716(95% CI：0.648 ～ 0.784)，最佳切点为480 nmol，灵敏度为58.0%，特异度为79.4%；UFCCR为诊断指标的曲线下面积为0.729(95% CI：0.662 ～ 0.796)，最佳切点为6.84 ml，灵敏度为59.1%，特异度为78.7%。 结论： 在我院实验室条件下，24 h UFC用于诊断AI中SCS切点为480 nmol，UFCCR切点为6.84 ml，诊断价值中等，可用于临床参考。.
Keywords: Adrenal gland neoplasms; Sensitivity and specificity; Subclinical Cushing′s syndrome; Urinary free cortisol.