Predictive Factors of Outcomes in Personalized Radioactive Iodine (131I) Treatment for Graves’ Disease

Abstract

BackgroundGraves’ disease (GD) is the most common cause of hyperthyroidism in iodine-sufficient areas. Radioactive iodine 131I treatment (RIT), as the 1st therapeutic option, is widely accepted by doctors and patients. The aim of this study was to investigate factors influencing the success rate of calculated RIT in GD. MethodsThyroid function outcome (hyperthyroidism or euthyroidism/hypothyroidism) was verified retrospectively at least 1 year after RIT and was compared with presenting clinical characteristics and pre-RIT parameters in 167 patients with GD treated with 131I-iodide in the authors’ institute. ResultsAfter RIT, 83 patients (49.7%) became euthyroid, 64 patients (38.3%) became hypothyroid and 20 (12.0%) remained hyperthyroid. Multiple logistic regression analyses demonstrated that there was no statistically significant association between RIT outcomes and sex, age, history of GD, previous antithyroid drug treatment, thyroid hormone levels, thyroid gland mass or radioactive iodine 131I dosage. The only variables associated with the success rate were the course of disease over 6 months (odds ratio, 3.70; confidence interval, 1.75–7.17; P=0.014) and 2-hour radioactive iodine uptake (RAIU) >58.5% (odds ratio, 4.08; confidence interval, 2.03–7.83; P=0.005). Conclusionsour study has shown that a calculated approach for the treatment of GD was effective, but high failure rates were observed in patients presenting higher 2-hour RAIU, particularly those with 2-hour RAIU of more than 58.5%.