BACKGROUND: Selenium (Se) shows potential benefit in Graves' disease (GD) especially those with active Graves' ophthalmopathy(GO).  
OBJECTIVES: To evaluate the efficacy of Se supplementation among patients with GD and GO.
METHODOLOGY: We performed a meta-analysis of trials evaluating the efficacy of Se supplementation among adult patients with GD and active GO, versus either placebo or an alternative drug, and on top of standard therapy. Results were presented as mean differences, standard errors, and 95% confidence intervals,and graphically presented as forest plots.Estimates were calculated using the inverse variance method for continuous variables and pooled using the fixed effects model. I2 and Chi2 tests were used to assess heterogeneity.
RESULTS: Only  two  trials  were  ultimately  included  in  the  analysis. Both studies totaled 197 participants with GD and non-severe  GO  on  standard  therapy,  and  compared  Se  supplementation to placebo. The only common outcomes of  interest  were  changes  in  TSH  receptor  antibody  (TRAB)  and thyroid peroxidase antibody (TPOAB) titers. We found no statistically significant difference in either TRAB (95% CI,-1.38  [-3.19,  0.44],  p=0.14)  or  TPOAB  (95%  CI,  36.66  [-32.56, 105.88], p=0.30) titers between Se and placebo groups on follow  up.However,our analysis was limited by the small number of included studies, a small sample size, and lack of other synthesizable outcomes.
CONCLUSION: This is the  first  meta-analysis  summarizing  the available data on Se supplementation in patients with GD and  non-severe  GO.We found no statistically significant differences in both TRAB and TPOAB titers between Se and placebo groups. We recommend larger studies to validate these findings. 

Thyrotropin-binding Inhibitory Immunoglobulin ; Graves Ophthalmopathy ; Selenium ; Iodide Peroxidase ; Immunoglobulins, Thyroid-stimulating ; Graves Disease ; Thyroid Microsomal Antibodies ; Autoantibodies ; Forests ; Thyroid Gland