Health Sciences Department, University of Florence, Florence, Italy.
Meyer Children's Hospital IRCCS, Florence, Italy.
Endocrinol Diabetes Metab. 2024 Sep;7(5):e70000. doi: 10.1002/edm2.70000.
In childhood, growth hormone (GH) deficiency (GHD) diagnosis is based on auxological assessment and biochemical provocative tests, whose reliability remains disputed. Recently, several papers have been published on standardising the duration of some tests. The aim of our study was to analyse the possible length reduction of the L-DOPA provocative test.
We retrospectively investigated the response of GH to L-DOPA in 256 children, analysing 267 tests (some patients were retested over time for the persistence of severe auxopathy). We studied the same data considering GH peak threshold both at 8 ng/mL (Italian GHD cut-off) and at 10 ng/mL (international cut-off). Based on stimulation tests, patients were divided into two groups: GHD and no-GHD short children. We described the results in the whole population and then clustering for gender and pubertal stage. We termed as index the test stopped at 90 min.
The GH peak after L-DOPA mostly occurred at 60 min. The sensitivity of the index test was the highest, while the specificity was slightly higher using the 8 ng/mL threshold (specificity = 0.68; 95% CI 0.60-0.76) then using the 10 ng/mL threshold (specificity = 0.56; 95% CI 0.47-0.65) at 90 min. The two ROC curves showed moderate performance of the test at 90 min. While the negative predictive value was 100% in both tests, the positive predictive value was slightly better with 10 ng/mL cut-off. Considering the two groups established by GHD definition and placing a GH threshold at 10 ng/mL, stopping L-DOPA test time at 90 min would have changed the test result and subsequentially patient's classification in 3/267 of the analysed tests (1.1%), while with the Italian GH threshold value at 8 ng/mL in 7/267 of the tests (2.6%).
Our research shows that omitting 120-min time reduces L-DOPA test specificity, especially with GHD cut-off at 10 ng/mL.
在儿童时期，生长激素（GH）缺乏症（GHD）的诊断基于生长评估和生化激发试验，但这些方法的可靠性仍存在争议。最近，有几篇论文发表了关于一些试验持续时间标准化的内容。我们研究的目的是分析 L-多巴激发试验可能的缩短。
我们回顾性分析了 256 名儿童的 L-多巴激发试验中 GH 的反应，分析了 267 次试验（一些患者因严重生长障碍持续存在而在一段时间内进行了重复测试）。我们根据 GH 峰值阈值分别为 8ng/mL（意大利 GHD 截断值）和 10ng/mL（国际截断值）研究了相同的数据。基于刺激试验，患者被分为 GHD 和非 GHD 矮小儿童两组。我们描述了整个人群的结果，然后按性别和青春期阶段进行聚类。我们将 90 分钟时停止的试验称为索引试验。
L-多巴后 GH 峰值大多出现在 60 分钟。索引试验的灵敏度最高，而使用 8ng/mL 阈值时特异性略高（特异性=0.68；95%CI 0.60-0.76），然后使用 10ng/mL 阈值时特异性略高（特异性=0.56；95%CI 0.47-0.65）在 90 分钟时。两条 ROC 曲线显示 90 分钟时试验的性能中等。虽然两种试验的阴性预测值均为 100%，但使用 10ng/mL 截断值时阳性预测值略好。考虑到 GHD 定义建立的两组，并将 GH 阈值设置为 10ng/mL，在 90 分钟时停止 L-多巴试验时间将改变 3/267 次分析测试（1.1%）的测试结果和随后的患者分类，而使用意大利 GH 阈值值为 8ng/mL 时，7/267 次测试（2.6%）的测试结果和随后的患者分类。
我们的研究表明，省略 120 分钟的时间会降低 L-多巴试验的特异性，尤其是在 GHD 截断值为 10ng/mL 时。
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