Jonklaas Jacqueline
Division of Endocrinology, Georgetown University, Washington, District of Columbia, USA.
Curr Opin Endocrinol Diabetes Obes. 2017 Oct;24(5):356-363. doi: 10.1097/MED.0000000000000355.
A subset of patients being treated for hypothyroidism do not feel well while taking levothyroxine (LT4) replacement therapy, despite having a normal serum thyroid stimulating hormone level. Pursuing a relative triiodothyronine deficiency as a potential explanation for patient dissatisfaction, has led to trials of combination therapy with liothyronine (LT3), with largely negative outcomes. This review attempts to reconcile these diverse findings, consider potential explanations, and identify areas for future research.
Patients being treated with LT4 often have lower triiodothyronine levels than patients with endogenous thyroid function. Linking patient dissatisfaction with low triiodothyronine levels has fueled multiple combination therapy trials that have generally not shown improvement in patient quality of life, mood, or cognitive performance. Some trials, however, suggest patient preference for combination therapy. There continues, moreover, to be anecdotal evidence that patients have fewer unresolved symptoms while taking combination therapy.
The 14 trials completed to date have suffered from employing doses of LT3 that do not result in steady triiodothyronine levels, and having insufficient power to analyze results based on baseline dissatisfaction with therapy and patient genotype. Future trials that are able to incorporate such features may provide insight into what thyroid hormone preparations will most improve patient satisfaction with therapy.
一部分接受甲状腺功能减退治疗的患者，尽管血清促甲状腺激素水平正常，但在服用左甲状腺素（LT4）替代治疗时仍感觉不适。将相对三碘甲状腺原氨酸缺乏作为患者不满的潜在解释，引发了与碘塞罗宁（LT3）联合治疗的试验，但结果大多为阴性。本综述试图调和这些不同的发现，考虑潜在的解释，并确定未来研究的领域。
接受LT4治疗的患者的三碘甲状腺原氨酸水平通常低于具有内源性甲状腺功能的患者。将患者的不满与低三碘甲状腺原氨酸水平联系起来，推动了多项联合治疗试验，但这些试验总体上并未显示患者的生活质量、情绪或认知表现有所改善。然而，一些试验表明患者更喜欢联合治疗。此外，仍有轶事证据表明患者在接受联合治疗时未解决的症状较少。
迄今为止完成的14项试验存在以下问题：使用的LT3剂量无法导致三碘甲状腺原氨酸水平稳定，且没有足够的能力根据对治疗的基线不满和患者基因型来分析结果。未来能够纳入这些特征的试验可能会深入了解哪种甲状腺激素制剂最能提高患者对治疗的满意度。
