This study aimed to determine if selenium supplementation for a period of six months can decrease signs and prevent worsening of mild Graves’ ophthalmopathy among Filipino patients.

We conducted an open-label, assessor-masked, randomized controlled trial involving adult patients diagnosed with mild Graves’ ophthalmopathy. Participants were divided into two groups: one group received standard care (eye drops) alone (control group), while the other group received an additional 200 mcg/day oral selenium supplementation alongside standard care. Inclusion criteria encompassed adult patients with Graves’ hyperthyroidism presenting at least one sign of mild ophthalmopathy and a disease duration of less than 18 months. Statistical analyses were performed using independent sample t-test, Mann-Whitney U test and Fisher’s Exact/Chi-square test to compare means, ranks and frequencies between the two intervention groups. Paired sample t-test, Wilcoxon signed rank test and McNemar test were employed to assess changes from baseline to the third and sixth month observations.

A significant difference in clinical activity score (CAS) was observed between the selenium supplementation group and the control group. Initially, 14 eyes (33.33%) in the selenium group exhibited a CAS score of 0, which increased to 27 eyes (64.29%) at the third month of treatment and slightly decreased to 26 eyes (61.9%) at the sixth month. Conversely, the control group had 11 eyes with a CAS score of 0 at baseline, which increased to 16 eyes (38.1%) at three months and decreased to 14 eyes (33.33%) at the sixth month. The improvement in CAS was significantly associated with reductions in caruncle and plica swelling (p = 0.040). Further analysis revealed a statistically significant difference in CAS between the treatment and control groups (p = 0.017) at the sixth month mark.

Selenium supplementation provided significant benefit in reducing the signs and preventing deterioration of mild Graves’ ophthalmopathy, as indicated by improved CAS scores. Future research exploring baseline and end of treatment selenium concentrations in the Philippines is recommended to further substantiate these findings.