Quality of Life and Decision Regret Risk in Graves' Disease After Radioactive Iodine Therapy: A Prospective Cohort Study

OBJECTIVE: To identify pre-treatment determinants of hypothyroidism and decision regret (DR) following radioiodine (RAI) therapy in Graves' disease (GD), and to assess their longitudinal impact on health-related quality of life (QoL). METHODS: Prospective cohort of 500 GD patients receiving RAI. Machine learning models predicted hypothyroidism (3/6 months) and high DR using clinical indices, socio-economic factors, and ThyPRO-39 QoL scores. Longitudinal QoL was assessed at baseline, 3 and 6 months. RESULTS: Unmarried (p < 0.001), unemployed (35.50 ± 23.15 vs. 27.01 ± 6.95; p = 0.032), and higher income patients (> 5000 CNY/month: 29.67 ± 6.94 vs. 26.10 ± 7.95; p = 0.018) had significantly higher DR. Longer pre-RAI medication (> 12 months: 30.31 ± 15.96 vs. 27.48 ± 10.42; p = 0.015) increased regret. Hypothyroidism models showed poor discrimination (AUC ≤ 0.59). DR prediction was robust (LR AUC = 0.81), driven by pre-treatment stress (β = 1.32, p < 0.001) and anxiety (β = 0.98, p = 0.003). QoL improved in goitre (p < 0.001) and hypermetabolic symptoms (p < 0.001) at 3 months, while overall QoL (p < 0.001) and depression (p = 0.006) improved by 6 months. Cognitive deficits persisted beyond 3 months (p > 0.05). CONCLUSION: Non-clinical factors (marital/employment/income status) and psychological states strongly predict post-RAI regret. Hypothyroidism remains unpredictable, but high DR risk can be accurately identified (AUC = 0.81) for targeted intervention. Persistent cognitive impairment requires clinical attention despite biochemical normalisation.