Prognostic Factors for Antithyroid Drug Treatment Failure in Graves’disease Patients

Abstract

Background: There are three main options in management of Graves’ disease in adults; antithyroid drug, radioiodine ablation and thyroidectomy. The patient’s treatment selection depends on some clinical characteristic and patient’s need. Although half of Graves’ disease patients failed after conventional antithyroid drug treatment for 12 – 24 months and underwent radioiodine ablation or surgery (although some patients still continue antithyroid for more than 2 years and achieve remission), the majority of patients choose antithyroid drug treatment first due to the less invasive therapy.
Objective: To assess prognostic factors for antithyroid drug treatment failure in Graves’disease patients.
Methods: A retrospective observational cohort design study was conducted. Graves’disease patients who visited and followed up treatment at Surin Hospital from November 2019 to September 2021 were reviewed. Clinical data, history, physical signs and laboratory data were collected. Univariable and multivariable logistic regression analyses were used to evaluate the risk factors for antithyroid drug treatment failure.
Results: Of the 460 Graves’ disease patients, 227 patients failed antithyroid drug treatment and 233 patients achieved remission from antithyroid drug. Prognostic factors for prediction of antithyroid drug treatment failure included history of relapsed Graves’ disease (OR=3.06, 95% CI=1.80-5.21, p <0.001), thyroid gland size 45 gram or larger (OR=4.57, 95% CI=2.80-7.46, p <0.001), presence of thyroid related orbitopathy (OR=2.13, 95% CI=1.15-3.96, p =0.016), initial FT4 (OR=1.37, 95% CI=1.10-1.69, p =0.004) and methimazole dose at 6th month during treatment 15 gram/day or more (OR=9.20, 95% CI=4.73-17.89, p <0.001).
Conclusion: Graves’ disease patients who have prognostic factors as mentioned above tend to fail after antithyroid drug treatment. Physician should suggest them for other therapeutic options.