Chulalongkorn Medical Journal


Background: Current treatments of Graves’ disease have their own advantages and disadvantages. Radioactive Iodine (RAI) is an effective treatment but most of the patients will develop hypothyroidism.Objective: To study the results of treatment of Graves’ disease treated with RAI and to identify factors those could influence the outcomes.Methods: In all, 1,168 Graves’ disease patients who were treated with RAI were evaluated on their thyroid function for 1 - 26 years. The results of treatment were recorded in associated with patient’s gender, age, estimated gland size, pretreatment antithyroid drug and dose of RAI.Results: From 1,168 patients, 939 were females (80.4%), 1,098 (94.0%) received RAI from King Chulalongkorn Memorial Hospital, 64 (5.5%) were treated at Rajavithi Hospital. The incidence of hyperthyroid/euthyroid/hypothyroid was 34.3%/29.5%/36.1% , 22.0%/33.1%/44.9% and 2.1%/22.1%/75.8% at 1, 2 and 10 year after RAI therapy, respectively. Premedication with methimazole (MMI) or propylthiouracil (P.T.U.) reduced the effectiveness of RAI (P < 0.001). Patients with hypothyroid had younger age than those with hyperthyroid (P < 0.002) and euthyroid (P < 0.001). Patients with hyperthyroid had larger gland size than those with hypothyroid (P = 0.004) and euthyroid (P < 0.001) and received higher dose of RAI (P < 0.001). There were no differences in treatment outcome between gender and two medical centers.Conclusions: Premedication with either MMI or P.T.U. reduce RAI efficacy. Patients with larger gland size or older increase rate of treatment failure. Higher dose of RAI may be advisable to increase treatment efficacy.


Faculty of Medicine, Chulalongkorn University

First Page


Last Page