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Selenium Supplementation Versus Placebo in Patients With Graves' Hyperthyroidism

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

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT01611896
Acronym
GRASS
Enrollment
431
Registered
2012-06-05
Start date
2012-10-31
Completion date
2024-08-31
Last updated
2025-02-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Graves' Hyperthyroidism

Keywords

Graves' hyperthyroidism, Graves' disease, Selenium, Quality of Life, ThyPRO, Autoimmunity

Brief summary

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.

Interventions

DIETARY_SUPPLEMENTSelenium

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.

OTHERPlacebo

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.

Sponsors

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

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

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

Design outcomes

Primary

MeasureTime frameDescription
Proportion of participants with the composite outcome of 'ATD treatment failure'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

MeasureTime frameDescription
Proportion of participants who has thyroid hyperfunction (TSH <0.1) during the last 12 months (± 1 month) of the intervention periodLast 12 months (± 1 month) of the intervention period
Proportion of participants who has been referred to ablative therapy (radioactive iodine or thyroid surgery) at some point during the entire intervention periodIntervention period (24-30 months)
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 questionnaireFirst year after randomisation, and at the end of the intervention period (24-30 months)
Level of TRAb at 18 months, and at the end of the intervention period (24-30 months)18 months, and at the end of the intervention period (24-30 months)
Proportion of participants who receives ATD treatment (at any level) during the last 12 months (± 1 month) of the intervention periodLast 12 months (± 1 month) of the intervention period
Eye symptoms (ThyPRO subscale) during first year after randomisation, and at end of the intervention period (24-30 months)First year after randomisation, and at end of the intervention period (24-30 months)
Number of participants with adverse reactions during the intervention periodIntervention 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.
Number of participants with serious adverse events during the intervention periodIntervention 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.
Hyperthyroid symptoms (ThyPRO subscale) during first year after randomisationFirst year after randomisation

Countries

Denmark

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 23, 2026