Radioiodine Treatment in Autoimmune Hyperthyroidism: Analysis of Outcomes in Relation to Dosage

Background versy exists regarding the optimal dose of radioiodine (131I) therapy in autoimmune hyperthyroidism (i.e., Gravesʹ Disease). s er to evaluate the efficacy and safety of high dose 131I therapy in autoimmune hyperthyroidism, a retrospective review of patients who received 131I therapy for Gravesʹ disease from 1980 to 2000 in the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City was carried out. s udy population consisted of 596 autoimmune hyperthyroid patients with a mean age of 35 years. The mean follow-up period was 10.31 ± 2.37 years. Remission of hyperthyroidism occurred in 81.9%, persistent hyperthyroidism was recorded in 14.4% and recurrence in 3.7%. 131I doses of 5–9 mCi (185–333 MBq) and ≥20 mCi (≥740 MBq) were associated with remission rates of 65.5% and 87.7% respectively. Remission occurred earlier and more often with high doses of 131I. The high-dose group (20–30 mCi [740–1110 MBq]) had the lowest rate of persistence (9.7, 27.5 and 34.3%, for 20–30 [740–1110 MBq], 10–14 [370–518 MBq] and 5–9 [185–333 MBq] mCi, respectively p <0.05) and hypothyroidism occurred earlier in this group (p = 0.05). sions ion of autoimmune hyperthyroidism is more likely with doses of 20–30 mCi (740–1110 MBq).