Therapeutic Response to Radioactive Iodine Treatment in Graves' Disease / 대한내분비학회지

BACKGROUND: Prediction of therapeutic response to radioactive iodine (RAI) in Graves disease is poorly understood. Although thyrotropin binding inhibitor immunoglobulin (TBII) level is a strong index for relapse after antithyroid drug treatment, conflicting results are described regarding its prognostic significance in Graves disease treated with RAI. This study is to evaluate possible prognostic factors including TBII wbich affect the outcome of RAI therapy in Graves disease. METHODS: Two hundred and one patients with Graves disease who were followed for over 12 months after RAI treatment were studied retrospectively. The subjects were divided into hypothyroid, euthyroid and hyperthyroid groups, based on the thyroid function evaluated at 12 months after RAI therapy. We evaluated the association of clinical parameters including patients age, goiter size, degree of hyperthyroidism and TBII index with outcome of RAI treatment. RESULTS: In Graves disease, response rate to RAI was 70.1% (hypothyroid 22.4% and euthyroid 47.7%) until 12th month. The mean age of hypothyroid group was 40+/-11 years, significantly older than that other groups (euthyroid: 33+/-12, hyperthyroid: 35+/-13, p<0.05). Initial level of thyroid function, duration of antithyroid drug treatment prior to RAI, goiter size and dosage of RAI were not significantly different between the groups. There were 61 patients who had both TBII tests before and after RAI. Twelve had negative TBII and 49 had positive TBII before RAI admini-stration. The rate of unremitted hyperthyroidism after RAI therapy was significantly lower in patients with negative TBII than in those with positive TBII prior to RAI treatment( 0% versus 46.9%, p<0.05). CONCLUSION: Graves patients with positive TBII prior to RAI therapy were associated with lower therapeutic response to RAI than those with negatve TBII. And old age was associated with the development of early hypothyroidism after RAI therapy. These results suggest these factors be also considered in the treatment of Graves disease with RAI.

Clinical Characteristics of Graves' Disease Patients with Undetectable Thyrotropin Binding Inhibitor Immunoglubulin (TB2) / 대한내분비학회지

Background: Graves disease is an autoimmune disease caused by TSH receptor antibodies. Thyrotropin binding inhibitor immunoglobulins(TBII) are detected in most Graves patients, but some patients have no TBII activities in their sera. It is unknown whether the clinical features of TBII-positive patients are different from those of TBII-negative patients. Methods: To evaluate the prevalence of TBII-negative Graves' patients and its clinical differences from TBII-positive patients, we examined TBII by radioreceptor assay in 686 consecutive untreated Graves patients. We found 84 TBII-negative patients(15 men and 69 women, mean age ±EM: 40.9±.4 years) and compared their clinical characteristics with 87 TBII-positive patients (22 men and 65 women, mean age±EM: 39.9±.5 years) who were selected randomly from the same patients group. Results: In this study, TBII was undetectable in 12.2% of patients with Graves' disease(84 of 686). TBII-negative group had a less weight loss than TBII-positive group. However, there was no significant differences in age, sex ratio, prevalence of ophthalmopathy, duration of illness and positive rate of family history for thyroid diseases between TBII-negative and