Valuable predictive features of relapse of Graves' disease after antithyroid drug treatment.

PURPOSE: Antithyroid drug treatment (ATDT) effectively achieves euthyroidism in patients with Graves' disease (GD). However, apparently successful treatment may be followed by relapse. We investigated the outcome of ATDT in Chinese patients with GD to identify predictive features of relapse.

METHODS: In total, 133 patients with mild to moderate goiter were included in this analysis. All patients received methimazole for 12 to 40 months and were subsequently followed up for at least 1 year. Lasting remission was defined as the presence of clinical and laboratory features of euthyroidism for ≥ 1 year after stopping methimazole.

RESULTS: Most patients (118 of 133, 88.7%) remained in remission after the follow-up period; 15 patients (11.3%) developed relapse. A history of GD, larger goiter at the time of drug withdrawal, a positive thyroid-stimulating antibody titer and restauration of low thyroid-stimulating hormone levels during the maintenance period were related to a subsequent risk of relapse according to stepwise logistic regression analysis results. However, other clinical and biological features (age, sex, initial goiter, ophthalmopathy, thyroxine and triiodothyronine levels and thyroglobulin antibody and thyroid microsomal antibody titers) did not reach statistical significance.

CONCLUSION: Regular, individualized ATDT achieved an 88.7% remission rate in Chinese patients with GD. The features associated with probable relapse were a history of GD, larger goiter at the time of drug withdrawal, a positive thyroid-stimulating antibody titer at the time of drug withdrawal and redevelopment of low thyroid-stimulating hormone levels during the maintenance period.