Predictive factors of radioactive iodine (RAI) treatment failure in the patients with Graves’ disease in Sunpasitthiprasong Hospital

Abstract

Background: The chosen treatment for Graves' disease with antithyroid drug (ATD) refractory disease or serious consequences from the condition these days is radioactive iodine (RAI, Iodine-131, I-131) therapy. However, upon therapy, RAI treatment failure was discovered. The patients, who suffer from prolonged hyperthyroidism and a higher risk of radiation exposure, must undergo RAI treatment again.

Objectives: To determine the success and failure rate of RAI treatment and to assess factors related with failure in the initial RAI treatment for Graves' disease in order to improve Graves' disease management.

Materials and Methods: This retrospective descriptive analytical study conducted was in patients with Graves’ disease who received the first dose of radioactive iodine (RAI) therapy in nuclear medicine department, Sunpasitthiprasong Hospital between April 2022 and April 2024. Data between groups were obtained and compared using Mann-Whitney U test and Fisher exact test. Logistic regression analysis was performed to evaluate factors associated with RAI treatment failure.

Results: A total of 540 patients were enrolled, with 431 females (79.81%) and a median age of 44. The patients in the success and failure groups after RAI therapy were 304 (56.30%) and 236 (43.70%), respectively. The failure group had significantly higher estimate initial thyroid gland size, FT3 level, and RAI treatment dose compared to the success group (P-value <0.001). These findings were consistent with Univariate logistic regression analysis (Crude OR = 1.01, P-value <0.001, Crude OR = 1.05, P-value = 0.002, and Crude OR = 1.11, P-value <0.001, respectively). However, Multivariate logistic regression analysis revealed that the only estimate initial thyroid gland size factor is significantly associated with treatment failure (adjusted OR = 1.02, P-value < 0.001). There was no significant association in the influence of age, gender, FT3 level, dose of RAI, type of antithyroid drugs used and duration of antithyroid drugs used on the treatment outcome.

Conclusions: This study found that a modest failure rate of 43.70%. The only factor of estimate initial thyroid gland size was significantly associated with treatment failure.