Graves disease is the most common cause of hyperthyroidism in non-endemic areas and antithyroid drugs are the preferred first-line therapy in many centers. The aim of this retrospective investigation was to verify the association of remission with the achievement of normal TSH and free-T4 during the first 18 months of treatment and to compare it with negative anti-TSH-receptor antibodies at 18 months, a marker with known prognostic value. All patients diagnosed with Graves disease from 2008 to 2015 were selected. Those with more than 2 years of follow-up and with synchronous determination of TSH, free-T4 (fT4), free-T3 and anti-TSH-receptor antibodies (TRAb) performed at our clinic were included. We compared TRAb titer, TRAb positivity, TSH and fT4, between the group that achieved remission and the one that did not, for the length of treatment and follow up. We obtained 71 patients with mean age of 47 years of which 76% were females. The mean follow-up after remission was 2 years. Remission was achieved in 28% patients after 18 months of treatment. There were no significant differences in sex or age among the 2 groups. No association was found between the development of hypothyroidism during therapy and remission. Negative TRAbs at 18 months associated with remission significantly (P<0.001) with a strength of association of 0.86. A non-supressed TSH accompanied by normal fT4 levels achieved during therapy was associated significantly with remission (P < 0.001) with a strength of association of 0.74. Logistic regression with this parameter could explain 59.8% of remissions after initial therapy with P<0.001. This profile of thyroid function was associated with negative TRAbs significantly (P<0.001). Achieving a non-suppressed TSH in the presence of normal fT4, during the first 18 months of therapy, associates with TRAb negativization and could predict remission in approximately 60% of patients.
20 - 23 May 2017
European Society of Endocrinology