Abstract
Objective: To report our experience in a large number of patients with hyperthyroidism following long-term continuous antithyroid therapy.
Methods: One thousand and twenty nine patients aged 10-79 (77% female) with diffuse toxic goiter were treated with methimazole (MMI) for 18 months. Within one year after discontinuation of MMI, hyperthyroidism recurred in 273 patients. Each patient who preffered one of 3 modalities of treatment was assigned according to his choice. Others (126 patients) were randomized into 2 groups for continuous antithyroid and radioiodine (RAI) treatment. Numbers of thyroid dysfunction, cell blood count, lipid profiles, bone mineral density, echocardiography, quality of life and total cost of management were assessed in a mean of 11.4 years of follow up.
Results: Mean age was 40.1±4.8 years. There were 139, 98 and 36 patients in RAI, MMI and surgery groups. Of those treated with RAI, 86 and 53 patients became hypo-and euthyorid. No serious complications occurred in any of the patients. Goiter rate was greater (56 vs 22, p<0.01) and TPOAb titer was higher (261±229 vs 51±87 IU/mL, p<0.001) in MMI than RAI treated patients. During 11.4 years of follow up, MMI treated showed 5.7% TSH level >5.0 mU/L and 6% TSH <0.3 mU/L; the corresponding values for post RAI hypothyroid patients on levothyroxine therapy were 15.8% and 8.4%, respectively (p<0.001). Other parameters were not different between two groups.
Conclusion: Long-term continuous MMI treatment is safe and may be offered as another choice of therapy after relapse of hyperthyroidism.