Thyroid hormone replacement for subclinical hypothyroidism

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.

Published Online: 21 JAN 2009

Assessed as up-to-date: 30 MAY 2006

DOI: 10.1002/14651858.CD003419.pub2

Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

Radioiodine therapy for differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases

Background

Differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases has been observed in follow-up studies. The management of this condition remains controversial. Most studies support blind radioactive iodine treatment while others negate this approach.

Objectives

To assess the effects of radioiodine therapy for differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases.

Search methods

Studies were obtained from computerised searches of MEDLINE, EMBASE, The Cochrane Library, China National Infrastructure (CNKI) and paper collections of conferences held in Chinese.

Selection criteria

Randomised controlled clinical trials and prospective controlled clinical trials.

Data collection and analysis

Two authors independently extracted data and interviewed authors of all potentially relevant studies by electronic mail to verify randomisation procedures. One author entered data into a data extraction form and the second one verified the results of this procedure.

Main results

Because of the absence of any suitable randomised or prospective controlled trial in this area, results currently cannot be presented.

Authors' conclusions

The currently available evidence is insufficient to reliably assess the potential of radioiodine treatment for differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases.

Published Online: 21 JAN 2009

Assessed as up-to-date: 30 MAY 2008

DOI: 10.1002/14651858.CD006988.pub2

Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

The Biopsy-Proven Benign Thyroid Nodule: Is Long-Term Follow-Up Necessary?

Background

Thyroid nodules are common, and of those biopsied by fine-needle aspiration (FNA), the majority will be benign colloid nodules (BCN). Current guidelines suggest these BCN should be followed by ultrasonographic examination (US) every 3 years, with no endpoint specified. This study evaluated if long-term follow-up of benign thyroid nodules was associated with change in treatment or improvement in diagnosing a missed malignancy compared with short-term follow-up.

Study Design

All patients with FNA-based diagnosis of BCN at our institution from 1998 to 2009 were identified. Patients observed after the diagnosis were divided into short-term follow-up (<3years) and long-term follow-up (≥3years). Rates of repeat FNA, thyroidectomy, and malignancy detection were compared.

Results

Of 738 patients with BCN, 92 patients underwent thyroid resection after the initial US. Six hundred forty-six patients were observed, of which 366 returned for 1 or more follow-up US: 226 in the short-term group (median 13 months) and 140 in the long-term group (median 57 months). There were more follow-up US in long-term vs short-term (medians 4 vs 2, p < 0.01), more repeat FNAs in the long-term group (18 of 140 vs 8 of 226, p < 0.01); but no difference in interval thyroidectomies (13 of 140 vs 31 of 226, p = 0.25) or malignant final pathology (0 of 13 vs 2 of 31, p > 0.99). For all patients undergoing surgery, pathology was malignant in 2 of 136 (1.5%).

Conclusions

Long-term follow-up of patients with BCN is associated with increased repeat FNA and US without improvement in the malignancy detection rate. After 3 years of follow-up, consideration should be given to ceasing long-term routine follow-up of biopsy-proven BCN.

Journal of the American College of Surgeons

Volume 217, Issue 1 , Pages 81-88, July 2013