原发性甲状腺功能减退症中的血清促甲状腺激素。原发性甲状腺功能减退症中每日左甲状腺素最佳剂量的一个可能预测指标。

Serum thyrotropin in primary hypothyroidism. A possible predictor of optimal daily levothyroxine dose in primary hypothyroidism.

作者信息

Kabadi U M, Jackson T

机构信息

Endocrine Section, Veterans Affairs Medical Center, Phoenix, Ariz, USA.

出版信息

Arch Intern Med. 1995 May 22;155(10):1046-8.

PMID:7748047

Abstract

BACKGROUND

Pretreatment thyrotropin levels may be a reliable predictor of the optimal daily dose of levothyroxine sodium in patients with primary hypothyroidism. However, the older method of serum thyrotropin determination, with the reference range of less than 1 to 8 mU/L, has given way to a newer, supersensitive thyrotropin assay, with a reference range of 0.5 to 5.0 mU/L. Thus, at present, the previously established relationship between the levothyroxine dose and the pretreatment serum thyrotropin concentration may not be reliable in predicting the optimal daily dose of levothyroxine.

METHODS

We reassessed the relationship between the optimal daily levothyroxine dose and the pretreatment serum thyrotropin concentration as determined by the newer assay in 192 consecutive patients with primary hypothyroidism referred to an endocrinology clinic over a period of 4 years.

RESULTS

The optimal daily dose of levothyroxine sodium ranged from 25 to 225 micrograms, with most patients (65%) requiring 100 to 150 micrograms/d and a median dose of 125 micrograms. Multiple regression analysis documented a significant curvilinear correlation between the mean pretreatment serum thryrotropin concentration and the optimal daily levothyroxine dose for individual groups divided according to available tablet strengths (r = .994, P < .001). A simple linear regression was also significant (r = .92, P < .001), although with an intercept much higher than the minimum levothyroxine sodium dose of 25 micrograms/d. However, the relationships markedly improved when the linear regressions were determined separately for two further subgroups at the median daily dose of 125 micrograms, providing equations to predict even the smallest optimal daily dose of levothyroxine.

CONCLUSION

Pretreatment thyrotropin levels determined by new assays may also provide a useful guideline in determining the optimal daily maintenance dose of levothyroxine in patients with primary hypothyroidism.

摘要

背景

在原发性甲状腺功能减退患者中，治疗前促甲状腺激素水平可能是左甲状腺素钠最佳日剂量的可靠预测指标。然而，血清促甲状腺激素测定的旧方法，其参考范围为小于1至8 mU/L，已被更新的超敏促甲状腺激素测定法所取代，后者的参考范围为0.5至5.0 mU/L。因此，目前，先前确立的左甲状腺素剂量与治疗前血清促甲状腺激素浓度之间的关系在预测左甲状腺素最佳日剂量方面可能并不可靠。

方法

我们重新评估了在4年期间转诊至内分泌门诊的192例连续原发性甲状腺功能减退患者中，通过新测定法测定的左甲状腺素最佳日剂量与治疗前血清促甲状腺激素浓度之间的关系。

结果

左甲状腺素钠的最佳日剂量范围为25至225微克，大多数患者（65%）需要100至150微克/天，中位剂量为125微克。多元回归分析表明，根据可用片剂强度划分的各个组中，治疗前血清促甲状腺激素平均浓度与左甲状腺素最佳日剂量之间存在显著的曲线相关性（r = 0.994，P < 0.001）。简单线性回归也具有显著性（r = 0.92，P < 0.001），尽管其截距远高于左甲状腺素钠的最小日剂量25微克/天。然而，当以125微克的中位日剂量分别对另外两个亚组进行线性回归时，这种关系显著改善，从而提供了甚至可以预测左甲状腺素最小最佳日剂量的方程。