Thyroid Peroxidase Antibody Positivity is Associated With Relapse-Free Survival Following Antithyroid Drug Treatment for Graves Disease

Objective: Graves’ disease is an autoimmune disease characterized by production of autoantibodies directed against the thyroid gland. Thyrotropin-receptor antibodies (TRAbs) are clearly pathogenic, but the role of thyroidperoxidase antibodies (TPOAbs) in Graves disease is unknown. Methods: We retrospectively studied whether TPOAb positivity reduced risk of relapse following antithyroid drug (ATD) treatment in newly diagnosed Graves disease. Results: During follow-up of 204 patients with TRAb-positive Graves disease, 107 (52%) relapsed following withdrawal of ATD. Mean age was 40.0 years, and 82% were female. The average duration of ATD treatment was 23.5 months and was not different between patients who relapsed and those with sustained remission. Absence of TPOAbs significantly increased risk of Graves relapse (odds ratio, 2.21). Male sex and younger age were other factors significantly associated with increased risk of relapse. Conclusion: TPOAb positivity significantly improves the odds of remission following ATD treatment in newly diagnosed Graves’ disease.