Analysis of risk factors of rapid thyroidal radioiodine-131 turnover in Graves’ disease patients

Rapid iodine-131((131)I) turnover in the thyroid gland is an important feature of Graves’ disease (GD) and also a strong predictor of radioiodine therapy failure. The aim of this study was to explore the predictors of rapid (131)I turnover. The clinical data on 2543 patients were retrospectively reviewed. Patients were divided into 2 groups depending on present or absent with rapid (131)I turnover defined as a 4-hour to 24-hour (131)I uptake ratio of ≥1. Overall, 590 cases (23.2%) had a rapid (131)I turnover. In the univariate analysis, gender, age, FT(3)/FT(4) concentration, disease duration, with or without antithyroid drugs (ATD), time of ATD, thyroid weight and thyroid textures displayed significant differences. Cutoff values of age, FT(3) and thyroid weight to predict rapid (131)I turnover were 38 years, 35 pmol/l and 56 g by receiver operating characteristic curves. Binary logistic regression analysis further revealed higher probability of rapid (131)I turnover in patients with thyroid weight ≥56 g (odds ratio [OR]:3.7, 95% confidence interval [CI]: 3.032–4.559), age <38 years (OR:2.3, 95%CI: 1.906–2.856), FT(3) concentration ≥35 pmol/l (OR:7.6, 95%CI: 5.857–8.563) and females (OR:2.2, 95%CI: 1.757–2.791). In conclusion, larger goiters, younger age, higher FT(3) concentration and females are independently associated with rapid (131)I turnover in GD patients.