Erickson Dana, Natt Neena, Nippoldt Todd, Young William F, Carpenter Paul C, Petterson Tanya, Christianson Teresa
Division of Endocrinology, Diabetes, Metabolism and Nutirtion, Mayo Clinic College of Medicine, 200 1st Street SW, Rochester, Minnesota 55905, USA.
J Clin Endocrinol Metab. 2007 Aug;92(8):2972-6. doi: 10.1210/jc.2006-2662. Epub 2007 May 8.
The definitive diagnosis of Cushing's syndrome (CS) in the setting of mild disease, as well as exclusion of CS in the setting of conditions that might mimic this clinical entity (pseudo-Cushing's syndrome), continues to present a significant challenge to the clinician.
The aim of the study was to review characteristics of the combined dexamethasone-suppressed CRH stimulation test in patients evaluated at an academic center for the possibility of mild CS.
DESIGN, PATIENTS, AND METHODS: We conducted a retrospective review of 66 patients. A total of 51 patients underwent final statistical analysis: 21 (41%) had Cushing's disease, and 30 were considered to have pseudo-CS based on the clinical scenario, comorbidities, and follow-up. Sensitivity, specificity, and diagnostic accuracy of cortisol and ACTH levels for the diagnosis of Cushing's disease were calculated at 1 min before, and 15, 30, 45, and 60 min after CRH administration. Diagnostic cutoffs for each parameter were determined by minimizing the absolute difference between sensitivity and specificity. Diagnostic accuracy was characterized by the area under the receiver operating characteristic curve, determined using the trapezoid rule.
The highest diagnostic accuracy was provided by the serum ACTH level at 15 min post-CRH, in which the area under the receiver operating characteristic curve was 99.7%, and a cutoff of more than 27 pg/ml (>5.9 pmol/liter) provided a sensitivity of 95% and specificity of 97% for the diagnosis of CS. A 15-min post-CRH cortisol greater than 2.5 mug/dl (70 nmol/liter) provided a sensitivity and specificity of 90 and 90%, respectively.
Our results differ from previous studies because our data suggest that when using the combined dexamethasone-suppressed CRH stimulation test, a 15-min post-CRH ACTH value greater than 27 pg/ml (5.9 pmol/liter) had the highest diagnostic accuracy for the detection of CS. However, the sensitivity and specificity for this test were not statistically different from the sensitivity and specificity of other tests, such as those measuring post-CRH stimulated ACTH levels or post-CRH cortisol levels at other time points. Therefore, clinicians should be cautious about interpretation of suppression and stimulation tests in the diverse population of patients with hypercortisolism.
在轻度疾病情况下确诊库欣综合征（CS），以及在可能模拟该临床实体的情况（假性库欣综合征）中排除CS，仍然给临床医生带来重大挑战。
本研究的目的是回顾在一所学术中心接受评估的可能患有轻度CS的患者中联合地塞米松抑制的促肾上腺皮质激素释放激素（CRH）刺激试验的特征。
设计、患者和方法：我们对66例患者进行了回顾性研究。共有51例患者进行了最终统计分析：21例（41%）患有库欣病，30例根据临床情况、合并症和随访情况被认为患有假性CS。在注射CRH前1分钟以及注射后15、30、45和60分钟计算皮质醇和促肾上腺皮质激素（ACTH）水平对库欣病诊断的敏感性、特异性和诊断准确性。通过最小化敏感性和特异性之间的绝对差异来确定每个参数的诊断临界值。诊断准确性通过使用梯形法则确定的受试者操作特征曲线下面积来表征。
CRH注射后15分钟时血清ACTH水平的诊断准确性最高，受试者操作特征曲线下面积为99.7%，大于27 pg/ml（>5.9 pmol/升）的临界值对CS诊断的敏感性为95%，特异性为97%。CRH注射后15分钟时皮质醇大于2.5 μg/dl（70 nmol/升）的敏感性和特异性分别为90%和90%。
我们的结果与先前的研究不同，因为我们的数据表明，在使用联合地塞米松抑制的CRH刺激试验时，CRH注射后15分钟时ACTH值大于27 pg/ml（5.9 pmol/升）对CS检测的诊断准确性最高。然而，该试验的敏感性和特异性与其他试验（如在其他时间点测量CRH刺激后的ACTH水平或CRH刺激后的皮质醇水平的试验）的敏感性和特异性在统计学上没有差异。因此，临床医生在解释皮质醇增多症患者群体中不同的抑制和刺激试验结果时应谨慎。
