Is radioiodine more likely than antithyroid drugs to worsen ophthalmopathy in patients with Graves disease?

This Practice Point commentary discusses the findings and limitations of a systematic review by Acharya et al. that assessed the utility of radioiodine to treat Graves hyperthyroidism. The authors examined 10 randomized controlled trials, and focused on the potential causative relationship between radioiodine and Graves ophthalmopathy. They concluded that the risk of Graves ophthalmopathy following radioiodine therapy is higher than that after treatment with antithyroid drugs (relative risk [RR] 4.23). The risk of severe Graves ophthalmopathy was also found to be increased after treatment with radioiodine (RR 4.35). Glucocorticoid prophylaxis was highly effective in preventing disease progression in patients with pre-existing Graves ophthalmopathy (RR 0.03). Here, I highlight the issues to consider when interpreting and generalizing these results, such as the limitations imposed by the inconsistency of disease classification and description in the various trials. Although this systematic review highlighted the small but real risk of Graves ophthalmopathy progression following radioiodine therapy, it could not provide insight into the extent of this progression or identify which patients are at highest risk and so might benefit most from prophylaxis.