Selenium supplementation in inactive moderate to severe Graves' orbitopathy patients: a randomized controlled trial.

PURPOSE: This study was designed to evaluate the effect of selenium supplementation in inactive moderate-severe Graves' orbitopathy (GO) patients.

METHODS: This study was a single-center, placebo-controlled, double-masked, randomized trial. Inactive moderate-severe GO participants were randomized to receive six months of 200 micrograms/day of selenium supplementation or placebo. Thorough eye exams, clinical activity score (CAS), Graves' Ophthalmopathy quality of life questionnaire (GO-QOL), and serum selenium level were evaluated at baseline and 6 months after the interventions. The chi-squared or Fisher's exact test was used to compare categorical variables. The t-test and the paired t-test were used to compare continuous variables between two independent samples and two dependent samples, respectively.

RESULTS: A total of 25 participants were enrolled, 13 in the selenium group and 12 in the placebo group. Both groups had adequate baseline serum selenium levels at 98.96 ± 15.63 mcg/L and 102.55 ± 17.71 mcg/L, respectively. After 6 months of intervention, the selenium group showed a greater improvement in palpebral aperture (mean difference: -1.4 ± 1.7 mm, p  = .04) compared to the placebo group (-0.3 ± 2.7 mm). Notably, 5(41.67%) people in the placebo group developed larger palpebral apertures. Proptosis, ocular motility, and soft tissue signs did not change significantly. GO-QOL and CAS score improvement showed no statistically significant difference between both groups. Minor adverse effects were observed.

CONCLUSIONS: Selenium supplementation has a positive effect on eyelid aperture even in inactive moderate-to-severe GO patients with a sufficient baseline selenium level.