Objective: To determine the relationship between the positivity of third-generation TSH receptor antibody (TRAb) at the time of diagnosis and the cumulative methimazole dose used until remission in patients with Graves' disease.
Study design: Cross-sectional, descriptive study.
Place and duration of study: Department of Endocrinology and Metabolic Diseases, University of Health Sciences, Kartal Dr. Lütfi Kırdar City Hospital, Turkey from 2016 to 2018.
Methodology: Newly diagnosed Graves' patients were included in the study. The patients were divided into two groups according to whether they entered remission (n: 21) or not (n: 20), in the 18th month of methimazole treatment. In addition, the patients were further divided into two categories, according to TRAb status at the time of diagnosis as negative (n: 17) or positive (n: 24). The TRAb positivity and the cumulative methimazole dose they used until the month of remission were compared in these groups.
Results: The mean time to reach remission in 41 patients was 20.5 ± 3.1 months. TSH receptor antibody positivity rate was 58.5%. When the TRAb positivity of the groups was compared according to the state of having remission in the 18th month of the treatment, the positivity rate in the non-remission group was statistically significantly higher (p = 0.023).The time to go into remission was longer and the cumulative methimazole dose requirement was higher in the TRAb positive group (p <0.001).
Conclusion: Graves' disease patients with positive third-generation TRAb were found to have a lower rate of remission in the 18-month period compared to negative patients. Key Words: Graves' disease, TSH receptor antibody, Cumulative, Methimazole.