Factors Predicting Treatment Failure in Patients Treated with Iodine-131 for Graves′ disease

Treatment of Graves′ disease with iodine-131 ( ¹³¹ I) is well-known; however, all patients do not respond to a single dose of ¹³¹ I and may require higher and repeated doses. This study was carried out to identify the factors, which can predict treatment failure to a single dose of ¹³¹ I treatment in these patients. Data of 150 patients with Graves′ disease treated with 259-370 MBq of ¹³¹ I followed-up for at least 1-year were retrospectively analyzed. Logistic regression analysis was used to predict factors which can predict treatment failure, such as age, sex, duration of disease, grade of goiter, duration of treatment with anti-thyroid drugs, mean dosage of anti-thyroid drugs used, ^99m Tc-pertechnetate ( ^99m TcO ₄ ^- ) uptake at 20 min, dose of ¹³¹ I administered, total triiodothyronine and thyroxine levels. Of the 150 patients, 25 patients required retreatment within 1 year of initial treatment with ¹³¹ I. Logistic regression analysis revealed that male sex and ^99m TcO ₄ ^- uptake were associated with treatment failure. On receiver operating characteristic (ROC) curve analysis, area under the curve (AUC) was significant for ^99m TcO ₄ ^- uptake predicting treatment failure (AUC = 0.623; P = 0.039). Optimum cutoff for ^99m TcO ₄ ^- uptake was 17.75 with a sensitivity of 68% and specificity of 66% to predict treatment failure. Patients with >17.75% ^99m TcO ₄ ^- uptake had odds ratio of 3.14 (P = 0.014) for treatment failure and male patients had odds ratio of 1.783 for treatment failure. Our results suggest that male patients and patients with high pre-treatment ^99m TcO ₄ ^- uptake are more likely to require repeated doses of ¹³¹ I to achieve complete remission.

Keywords

Graves′ disease - iodine-131 therapy - technetium-99m uptake - treatment failure

Publication History

Article published online:
21 May 2022