Thyroid-Associated Ophthalmopathy after Treatment for Graves’ Hyperthyroidism with Antithyroid Drugs or Iodine-131

Context: Previous randomized trials have suggested an association between radioiodine treatment for Graves’ hyperthyroidism and thyroid-associated ophthalmopathy (TAO). Objectives: The aim of the study was to compare the occurrence of worsening or development of TAO in patients who were treated with radioiodine or antithyroid drugs. Design: We conducted a randomized trial (TT 96) with a follow-up of 4 yr. Patients, Setting, and Intervention: Patients with a recent diagnosis of Graves’ hyperthyroidism were randomized to treatment with iodine-131 (163 patients) or 18 months of medical treatment (150 patients). Early substitution with T4 was given in both groups. Main Outcome Measure: Worsening or development of TAO was significantly more common in the iodine-131 treatment group (63 patients; 38.7%) compared with the medical treatment group (32 patients; 21.3%) (P < 0.001). Results: The risk for de novo development of TAO was greater in patients treated with iodine-131 (53 patients) than with medical treatme...