A 6-year follow-up of a randomized prospective trial comparing methimazole treatment with or without exogenous L-thyroxine in Chinese patients with Graves' disease

Abstract

Objective: Antithyroid drug therapy is one of the main medical treatments for Graves' disease. There have been conflicting reports as to whether the addition of exogenous L-thyroxine improves remission rates more than antithyroid drugs alone. This randomized, controlled and prospective clinical trial was undertaken to investigate the long-term outcome of methimazole treatment with or without exogenous L-thyroxine in Chinese patients.

Methods: 145 patients with Graves' disease were randomly divided into 3 groups and all patients initially received 30 mg of methimazole daily for at least 1 month and then followed the titration -regimen with or without L-thyroxine: group 1 (30 mg→20 mg→15 mg→10 mg→5 mg); group 2 (30 mg→20 mg→15 mg→10 mg+L-thyroxine→5 mg+L-thyroxine); group 3 (30 mg→20 mg→15 mg→10 mg+L-thyroxine→5 mg+L-thyroxine→2.5 mg+L-thyroxine). The drug therapy was discontinued after 5 months of the final dose.

Results: 16 out of 46 patients in group 1 (34.8%), 12 out of 47 in group 2 (25.5%) and 16 out of 52 in group 3 (30.8%) had a recurrence of Graves' disease within 6-year follow-up after drug withdrawal. Survival Analysis showed no significant differences in the remission rates between any 2 groups, despite the remission rates in group 2 and 3 were slightly higher than that in group 1.

Conclusions: The addition of L-thyroxine to methimazole treatment in patients with Graves' disease neither improves nor prevents the remission or recurrence of Graves' disease in China.