唾液皮质醇对库欣综合征的诊断价值探讨

Diagnostic Value of Salivary Cortisol in Cushing's Syndrome

目的评价唾液皮质醇(SC)与血皮质醇(PTC)的相关性,探讨SC筛查库欣综合征的价值。方法以18例经病理证实的库欣综合征患者作为疾病组,13例单纯性肥胖患者作为疾病对照组,36例健康志愿者作为正常对照组,收集8∶00、16∶00、24∶00及1 mg地塞米松过夜抑制试验(DST)后次日8∶00的血液和唾液,收集24 h尿液并记录尿量。用电化学发光法检测唾液、血液和尿游离皮质醇(24 h UFC)浓度。结果SC与PTC在4个时间点呈显著直线相关,相关系数r值依次为0.71、0.74、0.78、0.71,总的相关系数r=0.73,P均<0.05;SC与24 h UFC在4个时间点也呈显著正相关(r值分别为0.75、0.70、0.76和0.58),库欣综合征组的午夜SC均值明显高于正常对照组和单纯性肥胖组(P<0.001);8∶00 SC以6.21 nmol/L作为临界值,筛查库欣综合征的灵敏度为100%,特异性为84.0%;若以8.33 nmol/L作为临界值,筛查库欣综合征的灵敏度为62.5%,特异性为100%;午夜24∶00 SC以2.80 nmol/L作为临界值,筛查库欣综合征的灵敏度为100%,特异性为93.9%;若以4.56 nmol/L作为临界值,筛查库欣综合征的灵敏度为93.8%,特异性为100%。结论SC与PTC及24 h UFC具有较好的相关性,午夜24∶00 SC是一种简单方便且无创的库欣综合征筛查指标,具有较高的灵敏度和特异性。

Objective To evaluate the usefulness of the measurement of midnight salivary cortisol（SC） in the initial diagnosis of Cushing＇s syndrome（CS）. Methods A total of 18 patients with pathologically confirmed CS were recruited in the study. Thirteen patients with pure obesity and 36 healthy people served as controls. Salivary samples at 8 ： 00, 16 ： 00, 24 ： 00 and 8 ; 00 the next day after the 1 mg dexamethasone suppression test（DST） were collected by a commercially-available saliva collection device, and assayed by Electro Chemiluminescence Immuno Assay （ECLIA）. Results There were highly significant correlations between salivary eortisol and plasma eortisol （PTC） at the 4 time points. The correlation coefficient was 0.73 （0.71, 0.74, 0.78 and 0.61 at the four time points,respectively） （P〈0.05）. Midnight salivary cortisol level in Cushing＇s Syndrome [（10. 58± 5. 17） nmol/L3 was significantly higher than healthy people [（1. 55± 0. 60） nmol/L]. The receiver operating characteristics curve （ROC） analysis showed a sensitivity of 100.00% and specificity of 84.00% at 8 ：00 with the cut-off point of 6.21 nmol/L. Conclusion The measurement of midnight salivary cortisol is a convenience and noninvasive screening test for the initial diagnosis of Cushing＇s Syndrome.