Dos Santos Patricia Borges, Gertrudes Larissa Nascimento, Conceição Flavia Lucia, de Andrade Bruno Moulin, de Carvalho Denise Pires, Vaisman Mario, Teixeira Patricia de Fatima Dos Santos
Post Graduation Program in Endocrinology, Medicine School, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Front Endocrinol (Lausanne). 2019 Jul 17;10:465. doi: 10.3389/fendo.2019.00465. eCollection 2019.
To evaluate the impact of metformin (MTF) use on TSH levels, thyroid volume and volume of benign thyroid nodules (TNs). Additionally, to study if iodine status influences the outcomes. A total of 23 euthyroid patients (42 TNs) with benign thyroid nodules, diagnosed by fine needle aspiration biopsy, were randomly assigned to MTF or placebo (P) use for 6 months. Serum TSH, homeostatic model assessment for insulin resistance (HOMA-IR), and urinary iodine concentrations (UIC) were assessed. Ultrasound was used to evaluate TNs and thyroid volumes (TV) and their variations throughout the study. Diabetic patients, those undergoing levothyroxine replacement, and/or using thyroid- or insulin level-influencing drugs were excluded. The sample consisted predominantly of patients without IR. Both intervention groups were similar regarding several confounding variables and showed a comparable median UIC. Serum TSH decreased significantly after MTF (-0.21 vs. 0.09 mUI/L in the P group; = 0.015). At 6 months, no significant variations were found between groups with respect to TN volumes, TV, HOMA-IR, or body mass index (BMI). However, a tendency toward enlargement of TV with placebo (16.0%; = 0.09) and a protective effect of MTF on growing TN (OR: 0.25; CI 0.05-1.20) was detected after excluding patients with IR (a lower UIC subgroup). The reduction on TSH levels with MTF maintained in the population without iodine insufficiency (-0.24 vs. +0.07 in the P group; = 0.046) and was accentuated in those with excessive or more than adequate UIC (-0.69; = 0.043). A protective effect of MTF on growing TN was suggested (OR: 0.11; IC: 0.02-0.84) in those with higher UIC. This study demonstrated that MTF caused a reduction in TSH levels in benign nodular goiter. This effect was more accentuated in patients with higher levels of UIC and was accompanied by a suggested protective effect on TN enlargement.
评估二甲双胍（MTF）的使用对促甲状腺激素（TSH）水平、甲状腺体积及良性甲状腺结节（TN）体积的影响。此外，研究碘状态是否会影响上述结果。通过细针穿刺活检确诊的23例患有良性甲状腺结节的甲状腺功能正常患者（42个TN）被随机分为两组，分别使用MTF或安慰剂（P），为期6个月。评估血清TSH、胰岛素抵抗稳态模型评估（HOMA-IR）及尿碘浓度（UIC）。在整个研究过程中，使用超声评估TN及甲状腺体积（TV）及其变化。排除糖尿病患者、接受左甲状腺素替代治疗的患者和/或使用影响甲状腺或胰岛素水平药物的患者。样本主要由无胰岛素抵抗的患者组成。两个干预组在几个混杂变量方面相似，且UIC中位数相当。MTF治疗后血清TSH显著降低（P组为-0.21 vs. 0.09 mUI/L；P = 0.015）。6个月时，两组在TN体积、TV、HOMA-IR或体重指数（BMI）方面未发现显著差异。然而，排除胰岛素抵抗患者（较低UIC亚组）后，发现安慰剂组有TV增大的趋势（16.0%；P = 0.09），MTF对生长中的TN有保护作用（OR：0.25；CI 0.05 - 1.20）。在无碘缺乏的人群中，MTF使TSH水平降低的作用持续存在（P组为-0.24 vs. +0.07；P = 0.046），在UIC过高或充足的人群中更为明显（-0.69；P = 0.043）。在UIC较高的人群中，提示MTF对生长中的TN有保护作用（OR：0.11；IC：0.02 - 0.84）。本研究表明，MTF可使良性结节性甲状腺肿患者的TSH水平降低。在UIC水平较高的患者中，这种作用更为明显，且对TN增大有潜在保护作用。
