Radioiodine therapy and Graves' ophthalmopathy

Appearances of and increases in Graves' ophthalmopathy (GO) have been reported after treatment of patients with hyperthyroidism with radioiodine. We sought to determine the rates of appearance or increase in manifestations of GO in American patients treated with radioiodine for hyperthyroidism. Methods: The study population, which consisted of 76 patients (range, 10.6-72 y), included 61 women and individuals of diverse ethnicity. The patients were followed for 1 y after radioiodine treatment. The clinical activity score (CAS) included 10 items of ophthalmic change that were evaluated at 2 and 6 mo and at 1 y; appearance of a new item scored 1 point. We evaluated interactions of 6 covariates-prolonged hyperthyroidism, prolonged hypothyroidism, smoking, treatment with an antithyroid drug (ATD), and serum levels of thyroid -stimulating immunoglobulin (TSI) and of high free T-3 (FT3)-With the numbers of patients with 2 or more CAS points and with exophthalmometer readings increased by at least 2 mm. In addition, patients completed a scored quality-of-life (QOL) questionnaire at baseline and at 1 y to assess eye symptoms. Results: The mean CAS points for all patients at 2 mo was 0.63 and was not significantly different at 1 y. In 9 of 10 CAS items, there were few patients affected at 1 y and for the most part there were fewer patients affected than at baseline. However, exophthalmometer readings increased in 39% of patients by a mean of 2.6 mm. Individual patients frequently exhibited increases and decreases in item manifestations. Exophthalmometer readings decreased by 2 mm or less in 13%. Of the covariates, only hyperthyroidism prolonged by at least 2.5 mo was significantly associated with 2 or more CAS points at 1 y; no covariate was significantly associated with the development of increased exophthalmometer readings. Eye symptoms recorded in the QOL were insignificantly improved over the year; symptoms did not correlate with CAS points or with exophthalmometer readings. Conclusion: After radioiodine treatment, no substantial change was seen in manifestations of CAS items except for a modest increase in exophthalmometer readings in 39% of patients. Manifestations of CAS items frequently appeared and disappeared. Prolonged hyperthyroidism is best avoided. Ocular symptoms were insignificantly fewer at 1 y after radioiodine therapy. The observed changes do not warrant prophylactic treatment of patients with steroids. Key Words: Graves' ophthalmopathy; radioiodine therapy; clinical activity score; quality-of-life questionnaire