潜在性甲状腺機能低下症:レボチロキシンRCT 総頸動脈IMT・動脈硬化進展予防効果みとめず

1年半程度では潜在性甲状腺機能低下症への積極治療の総頸動脈IMTなどへの動脈硬化効果認めず


潜在性甲状腺機能低下症、ここでは TSH 4.60-19.9 で、遊離サイロキシン(fT4)値参照範囲内の症例への治療RCT

介入：TSH正常化目標レボチロキシン量調整 vs プラシーボ
主要アウトカムは、超音波測定総頸動脈IMT（中膜内膜複合体）、プラーク最大厚


Impact of Thyroid Hormone Therapy on Atherosclerosis in the Elderly With Subclinical Hypothyroidism: A Randomized Trial
The Journal of Clinical Endocrinology & Metabolism, Volume 103, Issue 8, 1 August 2018, Pages 2988–2997, https://doi.org/10.1210/jc.2018-00279
Published: 28 May 2018  Article history

被検者　185名、平均年齢 74.1歳、女性 47% 、レボチロキシン割り付け 96名
ベースライン総体平均 TSH ± SD  6.35 ± 1.95 mIU/L
治療後　レビチロキシン群  3.55 ± 2.14 mIU/L プラシーボ割り付け群   5.29 ± 2.21 mIU/L  (P < 0.001)

治療期間 18.4ヶ月(IQR 12.2 - 30.0ヶ月）後、平均 CIMT レボチロキシン .85 ± 0.14 mm vs プラシーボ 0.82 ± 0.13 mm [群間差 = 0.02 mm; 95% CI, −0.01 to 0.06; P = 0.30]

頸動脈プラーク比率 は同等 n = 135; 70.8% under levothyroxine and 75.3% under placebo; P = 0.46)

最大頸動脈厚  2.38 ± 0.92 mm  vs 2.37 ± 0.91 mm  (群間差 −0.03; 95% CI, −0.34 to 0.29; P = 0.86)

性別、ベースラインTSH、既存心血管疾患による有意関連認めず

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Subclinical HypothyroidismJune 29, 2017
N Engl J Med 2017; 376:2556-2565
https://www.nejm.org/doi/full/10.1056/NEJMcp1611144
Subclinical Hypothyroidism

• Subclinical hypothyroidism is defined as an elevated thyrotropin level with a normal free thyroxine (T4) level. To confirm the diagnosis, a transient increase in thyrotropin should be ruled out by a repeat measurement of thyrotropin and free T4 after 2 to 3 months.；１回では判断しない、２−３ヶ月後TSH、fT4再検必要

• In up to 46% of patients with subclinical hypothyroidism who have a thyrotropin level of less than 7 mIU per liter, the thyrotropin level normalizes within 2 years.；TSH < 7mIU/Lなら４６％では、２年内にTSH正常 

• Subclinical hypothyroidism, particularly when the thyrotropin level is more than 10 mIU per liter, is associated with an increased risk of hypothyroid symptoms and cardiovascular events.； TSH  >10 mIU/Lなら甲状腺機能低下症・心血管イベントリスク増加 

• There are few data from randomized, controlled trials of levothyroxine therapy for subclinical hypothyroidism to inform the effects of treatment on cardiovascular outcomes.：心血管疾患への治療の影響に関する情報提供にはレボチロキシン治療RCTからの十分なデータ不足している 

• Treatment is generally recommended for persons 70 years of age or younger who have thyrotropin levels of at least 10 mIU per liter, although long-term benefits have not been shown.：長期効果は不明だが、治療は一般には７０歳以下の　TSH <10 font="" miu=""> 

• Among patients who have thyrotropin levels of less than 10 mIU per liter or who are older than 70 years of age, treatment decisions are based on individual patient factors (e.g., symptoms of hypothyroidism, a positive test for antibodies to thyroid peroxidase, or cardiac risk factors).；TSH <10 font="" miu="" peroxidase="">を行う

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