Early Levothyroxine Post Radioactive Iodine

Study Overview
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Brief Summary
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The study will try to answer the question of whether early treatment with levothyroxine at 4 weeks after radioactive iodine for Graves'disease will prevent overt hypothyroidism (low thyroid hormone levels).

Official Title
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Prevention of Overt Hypothyroidism Following Radioactive Iodine Therapy for Graves' Disease

Conditions
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Graves' Disease

Intervention / Treatment
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* Drug: Levothyroxine
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: -all adult patients (ages 18-70 years) with Graves' Disease (GD) who will receive radioactive iodine (RAI) ablation of the thyroid gland for treatment of GD Exclusion criteria: clinically manifest Graves' ophthalmopathy (GO) recent (<1 yr.) history of arrhythmias or any history of ventricular arrhythmias preexistent cardiomyopathy malnutrition psychiatric history that could get worse if patient remains persistently hyperthyroid unlikely to return for the planned follow-up visits unlikely to comply with the blood drawing schedule unlikely to complete the hypothyroid-Health Related Quality of Life (HDQL) and Thyroid Specific (TSQ) questionnaires

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Levothyroxine<br>In the intervention arm patients will start levothyroxine therapy at 4 weeks after RAI therapy. The initial dose of levothyroxine will be 25 mcg/day. It will be increased to 50 mcg/day 2 weeks later and then adjusted at 8 weeks post RAI based on a full face-to-face clinical and biochemical evaluation. | Drug: Levothyroxine<br>* Early initiation of levothyroxine after radioactive iodine (to start at 4 weeks).<br>* Other names: Thyroid hormone;|
| Placebo Comparator: Placebo<br>In the control arm patients will receive placebo capsules and be evaluated for levothyroxine therapy during a full face-to-face evaluation at 8 weeks. | Other: Placebo<br>* Placebo to start at 4 weeks after RAI<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Overt Hypothyroidism | Incidence of overt hypothyroidism at 8 weeks post radioactive iodine treatment (RAI). Overt hypothyroidism was defined as thyroid stimulating hormone (TSH) test result > 3.0 milliunits per liter (mIU/L) or thyroid hormone free T4 (fT4) < 0.8 nanograms per deciliter (ng/dL). Free T4 is the portion of total T4 thyroid hormone that is available to your tissues in your bloodstream. | 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Hypothyroid-Health Related Quality of Life | The mean change in Quality of life scores was measured by the Hypothyroid-Health Related Quality of Life (HRQL) questionnaire. This questionnaire consists of 27 questions specifying the severity of the discomfort or symptoms of hypothyroidism using a 5 point scale for each question with not at all=1 to all the time=5. Higher scores are associated with a lower quality of life. The change between weeks 4 and 8 were assessed using a hierarchical linear model. The primary parameter of interest from the model was the treatment by time interaction term. Time was a collection of indicator values representing each assessment point. | 4 weeks, 8 weeks | 
| Change in Thyroid Specific Quality of Life | The mean change in quality of life scores was measured by the Thyroid Specific Questionnaire (TSQ). This questionnaire consists of 12 questions ranked on a four-point scale for each question where 0 is 'better than usual' and 3 is 'much less than usual'. A higher score indicates higher levels of dissatisfaction and a lower quality of life. The change between weeks 4 and 8 were assessed using a hierarchical linear model. The primary parameter of interest from the model was the treatment by time interaction term. Time was a collection of indicator values representing each assessment point. | 4 weeks, 8 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Graves' disease, Radioactive iodine, Hypothyroidism