Intervention Review

Thyroid hormone replacement for subclinical hypothyroidism

  1. Heloisa Cerqueira Cesar Esteves Villar1,*,
  2. Humberto Saconato2,
  3. Orsine Valente3,
  4. Álvaro N Atallah4

Editorial Group: Cochrane Metabolic and Endocrine Disorders Group

Published Online: 18 JUL 2007

Assessed as up-to-date: 30 MAY 2006

DOI: 10.1002/14651858.CD003419.pub2


How to Cite

Villar HCCE, Saconato H, Valente O, Atallah ÁN. Thyroid hormone replacement for subclinical hypothyroidism. Cochrane Database of Systematic Reviews 2007, Issue 3. Art. No.: CD003419. DOI: 10.1002/14651858.CD003419.pub2.

Author Information

  1. 1

    Faculdade Estadual de Medicina de Marília, Departamento de Medicina Interna, Marília, São Paulo, Brazil

  2. 2

    Federal University of Rio Grande do norte, Department of Medicine, São Paulo, Vila Clementino, Brazil

  3. 3

    Universidade Federal de São Paulo / Escola Paulista de Medicina, Department of Internal Medicine, São Paulo, Brazil

  4. 4

    Universidade Federal de São Paulo / Escola Paulista de Medicina, Brazilian Cochrane Centre, São Paulo, SP, Brazil

*Heloisa Cerqueira Cesar Esteves Villar, Departamento de Medicina Interna, Faculdade Estadual de Medicina de Marília, Av. Cascata 123, Marília, São Paulo, 17515-300, Brazil. hvillar@famema.br.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 18 JUL 2007

SEARCH

 

Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Background

Subclinical hypothyroidism is defined as an elevated serum thyroid-stimulating hormone (TSH) level with normal free thyroid hormones values. The prevalence of subclinical hypothyroidism is 4% to 8% in the general population, and up to 15% to 18% in women who are over 60 years of age. There is considerable controversy regarding the morbidity, the clinical significance of subclinical hypothyroidism and if these patients should be treated.

Objectives

To assess the effects of thyroid hormone replacement for subclinical hypothyroidism.

Search methods

We searched The Cochrane Library, MEDLINE, EMBASE and LILACS. Ongoing trials databases, reference lists and abstracts of congresses were scrutinized as well.

Selection criteria

All studies had to be randomised controlled trials comparing thyroid hormone replacement with placebo or no treatment in adults with subclinical hypothyroidism. Minimum duration of follow-up was one month.

Data collection and analysis

Two authors independently assessed trial quality and extracted data. We contacted study authors for missing or additional information.

Main results

Twelve trials of six to 14 months duration involving 350 people were included. Eleven trials investigated levothyroxine replacement with placebo, one study compared levothyroxine replacement with no treatment. We did not identify any trial that assessed (cardiovascular) mortality or morbidity. Seven studies evaluated symptoms, mood and quality of life with no statistically significant improvement. One study showed a statistically significant improvement in cognitive function. Six studies assessed serum lipids, there was a trend for reduction in some parameters following levothyroxine replacement. Some echocardiographic parameters improved after levothyroxine replacement therapy, like myocardial relaxation, as indicated by a significant prolongation of the isovolumic relaxation time as well as diastolic dysfunction. Only four studies reported adverse events with no statistically significant differences between groups.

Authors' conclusions

In current RCTs, levothyroxine replacement therapy for subclinical hypothyroidism did not result in improved survival or decreased cardiovascular morbidity. Data on health-related quality of life and symptoms did not demonstrate significant differences between intervention groups. Some evidence indicates that levothyroxine replacement improves some parameters of lipid profiles and left ventricular function.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Thyroid hormone replacement for subclinical hypothyroidism

Subclinical hypothyroidism is a condition where some laboratory findings point at a thyroid gland not working properly. Patients with subclinical hypothyroidism may have vague, non-specific symptoms of actual hypothyroidism (for example dry skin, cold skin or feeling colder, constipation, slower thinking, poor memory) but these thyroid-related symptoms are not specific, that is why the diagnosis is based on test results. The fundamental question regarding people with subclinical hypothyroidism is whether they should be treated with thyroid hormones. To answer this question twelve studies of six to 14 months duration involving 350 people were analysed. Thyroid hormone therapy for subclinical hypothyroidism did not result in improved survival or decreased cardiovascular morbidity (for example less heart attacks or strokes). Data on health-related quality of life and symptoms did not demonstrate significant differences between placebo and thyroid hormone therapy. Some evidence indicated that thyroid hormone had some effects on blood lipids and technical measurements of heart function. Adverse effects were inadequately addressed in most of the included studies and have to be urgently investigated in future studies, especially in older patients.

 

摘要

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

背景

甲狀腺素補充應用於亞臨床甲狀腺低能症

亞臨床甲狀腺低能症定義為甲狀腺促素升高及游離甲狀腺激素正常。一般族群的盛行率為4%-8%,在超過60歲的女性盛行率為15%-18%。關於亞臨床甲狀腺低能症的合併症、臨床上的重要性、及病人是否需要被治療等方面有相當多的爭論。

目標

評估甲狀腺素補充對於亞臨床甲狀腺低能症的作用。

搜尋策略

我們尋找了Cochrane、MEDLINE、EMBASE、及LILACS醫學資料庫。關於目前在進行的試驗、參考文獻、及會議中的摘要我們也詳細的檢視。

選擇標準

所有的研究必須是隨機對照試驗,對照組為安慰劑或不治療的亞臨床甲狀腺低能症,且追蹤的時間至少為一個月。

資料收集與分析

由兩個獨立作業的作者來評估試驗的品質及選取資料。並連絡研究的作者以取得不足或額外的資料。

主要結論

總共選用了十二個試驗,包含共三百五十個人,試驗中追蹤的時間由六個月到十四個月不等。其中十一個試驗是比較甲狀腺素補充與安慰劑,只有一個試驗是比較甲狀腺素補充與不治療的亞臨床甲狀腺低能症病人。我們沒有發現任何一個試驗是評估心臟方面的併發症及死亡率。七個研究比較了症狀、情緒、及生活品質,沒有發現有統計學上的差異。其中一個試驗發現在認知功能上有統計學上的改善。六個試驗比較了血脂肪,發現在補充甲狀腺素的病人似乎可以改善某些血脂質指數。某些心臟指標也有改善的效果,例如心肌放鬆,在明顯等容心肌放鬆時間延長以及舒張功能障礙的病人可以看到改善。只有四個研究報告有副作用,但沒有統計學上的差異。

作者結論

在目前已知的隨機對照研究中,甲狀腺素補充並不會延長存活或減少心臟血管疾病.治療組在健康生活品質以及症狀方面沒有有意義的相差.某些証據顯示甲狀腺素可以改進血脂質及左心功能。

翻譯人

本摘要由臺灣大學附設醫院賴瑩純翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

甲狀腺素用於治療亞臨床甲狀腺低能症的效果仍不確定。亞臨床甲狀腺低能症在某些實驗的結果指向是甲狀腺在某些情況下沒有發揮效能。亞臨床甲狀腺低能的病人可能會有不明顯,不具特異性甲狀腺低下的症狀(比如說:皮膚乾、皮膚冷或感覺冷、便祕、思考緩慢、記憶力變差),但因為甲狀腺造成的症狀不具特異性,所以診斷的基礎在實驗室的測定結果。而最根本的問題是有亞臨床甲狀腺低能的人應不應該服用甲狀腺素。為了回答這個問題,我們分析了十二個為期六到十四個月的研究,人數共三百五十個人。   結果發現在使用甲狀腺素來治療亞臨床甲狀腺低能無法改善存活率或減少心臟血管方面的併發症(比如較少的心臟病或中風)。資料顯示健康相關生活品質及症狀在安慰組及甲狀腺素治療組沒有明顯差異。某些證據指出甲狀腺素治療對血脂及技術上測量的心功能有效果。副作用上沒有被明確的提出,因此迫切需要被研究調查,特別是在老人。