An Assessment of the Occurrence of Hypothyroidism in Patients Treated With RAI for Hyperthyroidism.

• Conditions: Nodule Solitary Thyroid; Toxic Multinodular Goiter; Radioactive Iodine-Induced Hypothyroidism
• Interventions: Radiation: radioacive iodine therapy

• Registration Number: NCT04663451
• Lead Sponsor: Universitair Ziekenhuis Brussel

Brief Summary

Low RAIU in patients with hyperthyroidism represents a common obstacle in the treatment with RAI. Therefore, a higher dose of RAI must be administered to cure hyperthyroidism in these patients. If we treat patients with thiamazole before starting RAI treatment, serum TSH will rise and result in an increase in iodine uptake by the thyroid gland. By doing so, the dose of RAI to be administered might be lowered to achieve similar therapeutic efficacy.

In the past, either calculated or fixed doses of 131I have been used to treat hyperthyroidism. The supposed advantage of a calculated dose compared to a fixed dose is the lowering of hypothyroidism frequency. However, various research papers have contradicted this statement.

Antithyroid drugs and RAI therapy have been widely used in the past, either in combination, or independent from one another. This has been done primarily in older patients, to reduce the risk of exacerbation of hyperthyroid symptoms after initiation of RAI.

The use of propylthiouracil has been shown to decrease the response rate after RAI due to radioprotective effects.

The use of methimazole and carbimazole did not have a negative effect on treatment failure, as long as the medication was discontinued various days before RAI administration. Although this statement is contested in other studies.

It is interesting to evaluate retrospective data of patients treated with RAI to evaluate prognostic factors of treatment respons and post RAI hypothyroidism.

Detailed Description

Not available

Study Timeline

• Study Start: 2020-09-11
• Primary Completion: 2020-11-24
• Study First Submitted: 2020-11-26
• Study First Submitted QC: 2020-12-04
• Study First Posted: 2020-12-11
• Status Verified: 2021-04
• Last Update Submitted: 2021-04-14
• Last Update Posted: 2021-04-19
• Study Completion: 2021-05

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 150

Inclusion Criteria

• Hyperthyroid patients, either subclinical or overt, who have undergone RAI treatment in the period of 2005-2015.

Exclusion Criteria

• Prior use of L-thyroxine
• Prior thyroid surgery
• Prior RAI treatment
• Patients with thyroiditis

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Toxic Nodule	radioacive iodine therapy	Hyperthyroid patients with underlying toxic nodule
Toxic multinodular goiter	radioacive iodine therapy	Hyperthyroid patients with underlying toxic multinodular goiter

Primary Outcome Measures

Name	Time	Method
The proportion of patients in which hypothyroidism occurs	Between 2-5 years after treatment	The proportion of patients in which hypothyroidism occurs after radioiodine treatment

Trial Locations

Locations (1)

Universitair Ziekenhuis Brussel; 🇧🇪 Brussels, Belgium