Objective: Radioactive iodine therapy (RAI) is an effective treatment for Grave’s disease. Lithium increases the iodine retention in the thyroid gland so that the adjuvant lithium to RAI treatment may increase the efficacy. This study compared the efficacy and safety of RAI given with or without lithium in the treatment of Graves’ disease.
Methods: This prospective randomized controlled study was performed in the patients with Grave’s disease confirming by immunological studies, radioactive nuclear and ultrasound imaging at a tertiary center hospital from June 2015 to June 2016. The patients were randomly assigned to RAI plus lithium (900 mg/day; 5 days before, 7 days after RAI) or RAI alone as a control group. The remission rates, time to remissions, adverse effects were evaluated at the 2nd, 4th, 6th-month follow-up visits.
Results: The 60 patients with Grave’s disease were included. Mean age was 42.5±12.3 year-old, 73.3% were female, 53.3% were recurrent hyperthyroidism and mean duration of disease was 48.1 months. Thyrotropin-receptor antibodies (TRAbs) were positive in 93.3%. Mean thyroids’ size was 37.4 grams calculated by ultrasound and mean iodine uptake was 70.0±12.7%. There were 30 patients with RAI plus lithium group and 27 patients of the control group completing the study. The remission rates occurred 23/30 (76.7%) in the RAI plus lithium group vs. 17/27 (63.0%) in the control group (P=0.26). Time to remission was 116.5±23.5 days in the RAI plus lithium group vs. 135.1±35.2 days in the control group (P=0.06). Mean serum lithium level was 0.7±0.3 mEq/L. No patient had a major side effect, however, the RAI plus lithium group reported higher polydipsia (51.6%) and polyuria (13.8%) than RAI group (p<0.01).
Conclusions: Lithium as an adjuvant therapy could not show superior benefits and might have higher adverse effects than standard RAI treatment in Graves’ disease.