In individuals with newly diagnosed Graves' hyperthyroidism, daily supplementation with selenium did not have any effects compared with placebo as add-on to standard antithyroid drugs, and the findings do not support the use of selenium supplementation in Graves' hyperthyroidism.
Key Findings
Results
Selenium supplementation did not reduce non-remission rates compared to placebo in newly diagnosed Graves' hyperthyroidism.
Non-remission was observed in 114 (53.3%) participants in the placebo group and 118 (54.6%) in the selenium group.
OR = 1.0 (95% CI: 0.7-1.5); P = 0.98.
Non-remission was defined as receiving ATD or remaining hyperthyroid (TSH <0.1 mIU/L) during the last 12 months of the intervention period or referral to ablative therapy (radioactive iodine or surgery).
The trial was a double-blinded, placebo-controlled, multi-centre design with 430 participants recruited between Dec 7th 2012 and Dec 3rd 2018.
Results
Selenium supplementation had no beneficial effect on quality of life compared to placebo on any ThyPRO scale.
QoL was serially assessed using the thyroid-related patient-reported outcome measure ThyPRO.
There was no beneficial effect of selenium, as compared with placebo, on any ThyPRO scale.
Participants' QoL at the end of the study was comparable to that of the general population sample.
QoL outcomes were compared with previously collected norm data from the general population.
Results
Thyrotropin receptor antibody levels were similar between the selenium and placebo groups at follow-up visits.
Thyrotropin receptor antibody levels were similar in the groups at the 18-month and end-of-study follow-up visits.
This indicates selenium supplementation did not meaningfully affect the autoimmune marker central to Graves' disease pathophysiology.
Methods
The GRASS trial was a double-blind, multi-centre, placebo-controlled RCT enrolling 430 participants with newly diagnosed Graves' hyperthyroidism.
Participants were randomised to daily supplementation with 200 μg selenium or placebo tablets.
Supplementation duration was 24-30 months, depending on the timing of antithyroid drug (ATD) withdrawal.
Recruitment occurred between Dec 7th 2012 and Dec 3rd 2018.