午夜血清皮质醇对库欣综合征诊断价值的评价

Value of midnight serum cortisol in the diagnosis of Cushing's syndrome

目的评价午夜血清皮质醇对库欣综合征患者的诊断价值,并计算最佳诊断切点。方法回顾性分析1991-2011年解放军总医院内分泌科收治并经病理确诊的285例库欣综合征患者的临床资料,同时收集146例临床怀疑库欣综合征后经试验检查排除库欣综合征患者的临床资料。所有患者住院期间测定8:00、16:00、00:00血清皮质醇,应用ROC曲线对午夜血清皮质醇的诊断效能进行评价,并与其余两个时间点进行比较,最终得出最佳诊断切点及对应的敏感性和特异性。结果8:00,16:00,00:00血清皮质醇ROC曲线下面积分别为0.904,0.930和0.984,诊断准确率分别为84.5%,91.5%和94.5%。鉴别库欣综合征与假库欣状态,8:00血皮质醇最佳切点为502 nmol/L(敏感性82.6%,特异性88.2%),16:00血皮质醇最佳切点为505.6 nmol/L(敏感性88.7%,特异性97.7%),00:00血皮质醇最佳切点为249 nmol/L(敏感性96.2%,特异性91.6%)。结论午夜血清皮质醇比8:00、16:00血清皮质醇诊断效能更高,午夜血清皮质醇以249 nmol/L为切点具有较高的敏感性和特异性。

Objective To evaluate the clinical value of the midnight serum cortisol in the diagnosis of Cushing＇s syndrome,and to explore the best cut-off value.Methods The clinical data of 285 patients surgically conformed as Cushing＇s syndrome and 146 patients with pseudo-Cushing＇s states in Chinese PLA General Hospital in 1991-2011 were retrospectively analyzed.The levels of serum cortisol were determined at 8：00,16：00,00：00 in all patients.ROC curve was used to evaluate the efficacy of the midnight serum cortisol in the diagnosis of Cushing＇s syndrome.The best cut-off value and its corresponding sensitivity and specificity were calculated.Results The AUCs of serum cortisol at 8：00,16：00,0：00 in diagnosing Cushing＇s syndrome were 0.904,0.930 and 0.984,respectively,and their corresponding diagnostic accuracies were 84.5%,91.5% and 94.5%.The best cut-off value of serum cortisol at 8：00 was 502 nmol/L with sensitivity of 82.6% and specificity of 88.2%,505.6 nmol/L at 16：00 with sensitivity of 88.7% and specificity of 97.7%,249nmol/L at 00：00 with sensitivity of 96.2% and specificity of 91.6%.Conclusion Midnight serum cortisol is better than those at the other time points in the diagnosis of Cushing＇s syndrome.Midnight serum cortisol level at 249 nmol/L has higher sensitivity and specificity.