Endocrine Abstracts

Introduction: According to the guideline for medical treatment of Graves’ disease by the Japan Thyroid Association in 2011, discontinuation of antithyroid drug is recommended when normal thyroid functions have been maintained for a certain period (≥6 months) after treatment with a minimum maintenance dose (mentioned below). We prospectively studied the remission rates in the patients with Graves’ disease.

Methods: The subjects were 108 patients with Graves’ disease, who were newly diagnosed from 2003 to 2008 (mean age, 46.2±13.2 years old, 22 men and 86 women). They were treated with methimazole (MMI) at the initial dose of 15 mg/day. MMI doses were gradually decreased to minimum maintenance dose (5 mg every other day).In this study, the duration of minimum maintenance dose was defined as 12 months. We finally discontinued MMI when their serum FT4 and TSH had been kept within normal range for 12 months. After discontinuation of MMI, they were followed every 4–6 months to confirm continuous remission.

Results: Eighty-six patients could reach minimum maintenance dose. The percentage of patients who reached minimum maintenance dose was 46% at 1 year, 68% at 2 years and 78% at 3 years. In 63 patients, in whom MMI was stopped after therapy for 23±8 months, remission rates were 86% at 1 year, 74% at 2 years and 67% at 3 years after MMI discontinuation. The levels of TRAb (TRAb-CT) and the ratio of TRAb positive patients at the time of drug cessation were 13% and 46% in remission group after 2 years. In relapse group within 2 years, those were 15% and 46%, respectively. There were no differences between the two groups.

Conclusion: The present study indicates that a minimum maintenance dose of MMI to keep euthyroid state for 12 months is a useful and practical procedure for treatment of Graves’ disease.In this protocol, TRAb might give little additional informations for prediction of remission.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector