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Completed

NCT Number: NCT01611896

Selenium Supplementation Versus Placebo in Patients With Graves' Hyperthyroidism

The purpose of this study is to investigate if selenium supplementation to the standard treatment with anti-thyroid drugs in patients with Graves' hyperthyroidism, will lead to a fewer people with anti-thyroid treatment failure and faster remission, in terms of better quality of life during the first year of treatment and more patients staying in remission.

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Key information

Conditions

Graves' Hyperthyroidism Autoimmune Diseases Endocrine System Diseases Exophthalmos Eye Diseases Goiter Graves Disease Hyperthyroidism Immune System Diseases Orbital Diseases Thyroid Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Endocrinology and Gastroenterology, Bispebjerg Hospital, Copenhagen, Denmark

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18 years or older.
  • Active Graves' hyperthyroidism (suppressed TSH (< 0.1) and positive TRAb) measured within the last two months prior to the inclusion date.
  • Written informed consent

Exclusion criteria

  • Major co-morbidity, making the participants unlikely to continuously receive trial intervention in the intervention period.
  • Previous treatment with radioactive iodine.
  • Current ATD treatment having been received for more than two months.
  • Treatment with immunomodulatory drugs, such as cyclosporine A, methotrexate, cyclophosphamide.
  • Allergy towards the components in the selenium and placebo pills.
  • Pregnant or breast-feeding women.
  • Intake of selenium supplementation above 70 µg per day (70 µg corresponds to the amount in a multivitamin tablet).
  • Unable to read and understand Danish.
  • Lack of informed consent

Treatment and study plan

Selenium

Dietary Supplement

100 µg tablets. The dose of daily supplement of selenium is set at 200 µg (two tablets). The duration of the intervention period is between 24-30 months. This is defined by the time of ATD treatment withdrawal, which is scheduled between approximately 12-18 months after randomisation. Selenium supplementation will continue 12 months after withdrawal of ATD treatment.

Other names: 'Selen, organisk selen', produced by Jemo-Pharm A/S

Placebo

Other

Placebo tablets, identical in regards to size, appearance, taste, smell, and solubility to the experimental intervention tablet will be produced by Jemo-Pharm A/S, http://www.jemo-pharm.dk/frame.cfm/cms/id=977/sprog=2/grp=6/menu=1/ (content as in section: Auxiliary agents). The placebo regimen will be identical to the selenium regimen, but consist of two non-active tablets per day for 24-30 months.

Primary outcomes

  1. Proportion of participants with the composite outcome of 'ATD treatment failure'

    Time frame: Last 12 months (± 1 month) of the intervention period

    'ATD treatment failure' is defined as:

    • The participant receives ATD treatment (at any level) during the last 12 months (± 1 month) of the intervention period; or
    • The participant has thyroid hyperfunction (TSH <0.1) during the last 12 months (± 1 month) of the intervention period; or
    • The participant has been referred to ablative therapy (radioactive iodine or thyroid surgery) at some point during the entire intervention period.

Secondary outcomes

  1. Proportion of participants who receives ATD treatment (at any level) during the last 12 months (± 1 month) of the intervention period

    Time frame: Last 12 months (± 1 month) of the intervention period

  2. Proportion of participants who has thyroid hyperfunction (TSH <0.1) during the last 12 months (± 1 month) of the intervention period

    Time frame: Last 12 months (± 1 month) of the intervention period

  3. Proportion of participants who has been referred to ablative therapy (radioactive iodine or thyroid surgery) at some point during the entire intervention period

    Time frame: Intervention period (24-30 months)

  4. Thyroid-specific QoL during the first year after randomisation, and at the end of the intervention period (24-30 months), as measured by the global score in the ThyPRO questionnaire

    Time frame: First year after randomisation, and at the end of the intervention period (24-30 months)

  5. Level of TRAb at 18 months, and at the end of the intervention period (24-30 months)

    Time frame: 18 months, and at the end of the intervention period (24-30 months)

  6. Hyperthyroid symptoms (ThyPRO subscale) during first year after randomisation

    Time frame: First year after randomisation

  7. Eye symptoms (ThyPRO subscale) during first year after randomisation, and at end of the intervention period (24-30 months)

    Time frame: First year after randomisation, and at end of the intervention period (24-30 months)

  8. Number of participants with adverse reactions during the intervention period

    Time frame: Intervention period (24-30 months)

    Participants will be asked to report about known adverse reactions (specified in the protocol) at 6 weeks, 12 weeks, 6 months, 12 months, 18 months, 24 months, and 12 months after ATD treatment withdrawal. In addition, participants are instructed to contact their trial contact person in case they experience adverse reactions.

  9. Number of participants with serious adverse events during the intervention period

    Time frame: Intervention period (24-30 months)

    To make sure we get information on serious adverse events, data on hospital admissions and mortality will be obtained through the national databases (the National Patient Registry and the Danish Civil Registration System) at the end of the trial. Also, participants are informed and instructed to contact their trial contact person in case they:

    • are admitted to a hospital for selenium intoxication;
    • experience a clinical picture indicative of selenium intoxication; or
    • experience a clinical picture unexpected, but suspected to be related to selenium intoxication.

Sponsors and collaborators

Lead sponsor

Rigshospitalet, Denmark

Other

Collaborators

  • Bispebjerg Hospital
  • Copenhagen Trial Unit, Center for Clinical Intervention Research
  • Danish Council for Independent Research
  • Esbjerg Hospital - University Hospital of Southern Denmark
  • Herlev Hospital
  • Hillerod Hospital, Denmark
  • Hvidovre University Hospital
  • Odense University Hospital
  • The Danish Council for Strategic Research

Registry information

Official study title

GRAves Selenium Supplementation Trial (GRASS) - an Investigator-initiated Randomised, Blinded, Multicentre Clinical Trial of Selenium Supplementation Versus Placebo in Patients With Graves' Hyperthyroidism

Acronym: GRASS

Important dates

Study start
2012
Primary completion
2021
Study completion
2024
First posted
Jun 5, 2012
Registry last updated
Feb 13, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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