Division of Endocrinology and Metabolism, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan,
Division of Endocrinology and Metabolism, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.
Horm Res Paediatr. 2019;92(1):45-51. doi: 10.1159/000502418. Epub 2019 Sep 25.
Congenital hypothyroidism (CH) can be divided into 2 types, transient CH (T-CH) and permanent CH (P-CH), depending on the requirement of levothyroxine (LT4) for life-long treatment. Several studies have recently reported that the LT4 dosage is useful for predicting the LT4 requirement, but none of the studies followed their patients to puberty.
To determine the cutoff value for the LT4 dosage as a predictor of the LT4 requirement after puberty in patients with CH.
The LT4 dosage and clinical data on 99 patients with CH who were followed at the participating hospitals from the neonatal period to 15 years of age or older were retrospectively analyzed. Based on their LT4 requirement at their last hospital visit, the participants were divided into the P-CH group (n = 75), who were treated with LT4, and the T-CH group (n = 24), who were not.
At age 1 year, a higher LT4 dosage was required for the P-CH group (median 3.75 vs. 2.88 µg/kg/day; p < 0.001). When the LT4 dosage cutoff value at age 1 year was set at 4.79 and 1.74 µg/kg/day, the specificity of P-CH and T-CH (for denying T-CH and P-CH, respectively) was 100 and 97%, respectively.
An LT4 dosage above 4.7 µg/kg/day and below 1.8 µg/kg/day at age 1 year may help predict P-CH and T-CH, respectively.
先天性甲状腺功能减退症（CH）可分为 2 种类型，即暂时性 CH（T-CH）和永久性 CH（P-CH），这取决于终身治疗对左甲状腺素（LT4）的需求。最近有几项研究报告称 LT4 剂量可用于预测 LT4 的需求，但这些研究均未对患者进行到青春期后随访。
确定 LT4 剂量的临界值，作为预测 CH 患者青春期后 LT4 需求的指标。
回顾性分析了 99 例在参与医院接受治疗的 CH 患儿的 LT4 剂量和临床数据，这些患儿从新生儿期随访至 15 岁或以上。根据他们最后一次就诊时的 LT4 需求，将参与者分为 P-CH 组（n=75），即需要 LT4 治疗的患者，以及 T-CH 组（n=24），即不需要 LT4 治疗的患者。
在 1 岁时，P-CH 组需要更高的 LT4 剂量（中位数 3.75 比 2.88 µg/kg/天；p < 0.001）。当 1 岁时 LT4 剂量的临界值设定为 4.79 和 1.74 µg/kg/天时，P-CH 和 T-CH 的特异性（分别为否认 T-CH 和 P-CH）分别为 100%和 97%。
1 岁时 LT4 剂量高于 4.7 µg/kg/天且低于 1.8 µg/kg/天可能有助于分别预测 P-CH 和 T-CH。
