Department of Neuropsychology, Transitional Learning Center, Galveston, TX 77550, USA.
Clin Endocrinol (Oxf). 2011 Mar;74(3):365-9. doi: 10.1111/j.1365-2265.2010.03935.x.
The diagnosis of growth hormone deficiency (GHD) in adults is established through growth hormone (GH) stimulation testing, which is often complex, expensive, time-consuming and may be associated with adverse side effects. The decision to perform GH provocative testing is influenced by clinical findings, medical history and biochemical evidence. We report in this study our experience using the glucagon stimulation test (GST) in assessing GHD in adult patients with traumatic brain injury (TBI) as it relates to baseline serum insulin-like growth factor-1 (IGF-1) concentrations.
A receiver operating characteristic (ROC) curve analysis was performed to determine the optimal IGF-1 cut-off for diagnosis of GHD at different potential diagnostic GST cut-off values (<3, <5, & <10 μg/l).
One hundred and thirty-eight patients (98 men and 40 women) with a documented history of moderate to severe TBI were assessed for GHD using serum IGF-1 concentrations and the GST.
IGF-1 values were compared with peak GH values obtained following the GST.
An IGF-1 cut-off value of 175 μg/l minimized the misclassification of GHD patients and GH-sufficient patients and provided a sensitivity of 83% and specificity of 40%, as well as a negative predictive power of 90% considering a criterion for peak GH response of <3 μg/l.
Our current findings are consistent with previous work assessing peak GH response using the insulin tolerance test (ITT) in a non-TBI sample, suggesting that diagnostic accuracy may be optimized if the GST is used when obtained serum IGF-1 concentrations are below 175 μg/l. While the decision to perform provocative testing to assess GHD in adult patients should be based on the clinician's clinical impression, the findings from this retrospective study can provide useful clinical information and serve as a guide.
成年人生长激素缺乏症（GHD）的诊断通过生长激素（GH）刺激试验确立，该试验通常复杂、昂贵、耗时，并且可能伴有不良反应。进行 GH 激发试验的决定受临床发现、病史和生化证据的影响。我们在此研究报告中介绍了在评估创伤性脑损伤（TBI）成年患者的 GHD 时使用胰高血糖素刺激试验（GST）的经验，因为它与基线血清胰岛素样生长因子-1（IGF-1）浓度有关。
进行了受试者工作特征（ROC）曲线分析，以确定在不同潜在诊断 GST 截止值（<3、<5 和 <10μg/l）下，用于诊断 GHD 的最佳 IGF-1 截止值。
138 例有中度至重度 TBI 病史的患者接受了血清 IGF-1 浓度和 GST 检查以评估 GHD。
将 IGF-1 值与 GST 后获得的峰值 GH 值进行比较。
IGF-1 截止值为 175μg/l 可最大限度地减少 GHD 患者和 GH 充足患者的误诊，并提供 83%的敏感性和 40%的特异性，以及考虑到峰值 GH 反应<3μg/l 的标准时为 90%的阴性预测值。
我们目前的发现与以前在非 TBI 样本中使用胰岛素耐量试验（ITT）评估峰值 GH 反应的工作一致，这表明如果在获得血清 IGF-1 浓度低于 175μg/l 时使用 GST，诊断准确性可能会得到优化。虽然进行激发试验以评估成年患者的 GHD 的决定应基于临床医生的临床印象，但这项回顾性研究的结果可以提供有用的临床信息并作为指导。
