Introduction: Optimal anti-thyroid regimen for management of Graves disease is still a matter of controversy. The aim of this study is determination of remission rate and long-term relapse rate after low-dose anti-thyroid drug therapy.
Method: This study is a long-term retrospective study. We selected 100 patients with the diagnosis of Graves disease that admitted to our endocrinology clinic from January 2000 until December 2010. All of patients were treated with anti-thyroid drugs at the initial dose of 20 mg/day of Methimazole then, doses were gradually decreased or changed 25 mg/day and discontinued when the patients were able to maintain euthyroid (normal fT4, fT3 and TSH). We recorded fT4, fT3, TSH measurements before starting drugs and then at 1, 2, 3, 6, 9, 12 months and 1, 2 and 5 years after starting of treatment to evaluate the remission and relapse rates.
Results: From all 100 Graves patients 85% were female and mean age was 53.5 years. 79% had diffuse goiter Graves disease and 21% had additional thyroid nodule. Percentage of patients with normal TSH was 20, 26.4, 51.6, 51.8, 65.4, and 81.3% after 3 months, 6 months, 1 year, 2 years, 5 years and 10 years respectively. Percentage of patients with normal free T3 was 79, 82.8, 88.9, 89.7, 90 and 98.2% after mentioned time intervals respectively. Also 72.1, 84, 90.1, 82.8, 88.5, 93.1% of patients have normal free T4 after mentioned time intervals respectively. We had 60.6 and 94.4% of complete remission after 1 and 2 years anti-thyroid drug therapy. TSH relapse rate after discontinuation of drug therapy was 2, 2, and 1% after 1, 2 and 5 years respectively.
Conclusion: Our study shows the effectiveness of low-dose anti-thyroid drug therapy in patients with Graves disease. So regarding lower side effects, we recommend low-dose anti-thyroid regimen for initial treatment of Graves hyperthyroidism.
30 Apr - 04 May 2011
European Society of Endocrinology