Iodine uptake variability as a predictive biomarker for radioiodine therapy outcomes in Graves Disease: Validation through multi‐time‐point RAIU assessment in a 1249‐patient cohort

Aims To investigate the impact of iodine uptake variability (IUV) as a predictive biomarker associated with Graves Disease (GD) on the success rate of radioiodine (RAI) therapy for GD within 36 months, and discover IUV indicators for predicting GD prognosis. Materials and Methods This retrospective study included patients with GD who underwent RAI therapy at the Second Affiliated Hospital of Anhui Medical University between October 2012 and October 2022. Spearman correlation and maximal information coefficient analyses were used, along with hierarchical clustering and Kaplan–Meier survival analysis. Logistic and Cox regression were performed, and receiver operating characteristic curves and random sampling were used for validation. Results The study comprised 1249 patients (333 males (26.66%) and 916 females (73.34%)). After a 3‐year follow‐up, there were 1014 (81.18%) and 235 (18.82%) cases in the success and failure groups, respectively. IUV was an independent factor for GD prognosis under RAI treatment. RAIU‐Range/Max was recommended as a representative indicator for IUV, with a clinical threshold of 28.8%. Conclusions In this study, we proposed and defined IUV as a predictive biomarker for GD, and verified its impact on the prognosis of GD treated with RAI. Low IUV was associated with a poor clinical prognosis.