TSH suppression combined with carbimazole for Graves' disease: effect on remission and relapse rates

OBJECTIVE: We studied the influence of TSH suppressive therapy combined with carbimazole (CBZ) on treatment outcome in Graves' disease. DESIGN: Open non-randomized prospective study. SETTING: University Hospital of Montpellier, France. SUBJECTS: Sixty-six consecutive patients without prior treatment were included. All the patients were treated initially with 30 mg of CBZ. After 1 month of treatment, one group continued CBZ alone (n = 23), another group received a combination of CBZ plus T3 (n = 19) and a third group received CBZ and 3,5,3'-triiodothyroacetic acid (Triac, n = 24). Therapy was stopped when remission was obtained based on clinical euthyroidism, normalization of FT4 and of early radioiodine uptake. Nine patients with medical treatment failure or major side effects requiring to stop antithyroid drugs underwent surgery or radioiodine therapy. Nine patients were lost to follow-up. The remaining 48 patients were available for analysis of both remission and relapse. RESULTS: The median duration of therapy was 18 months (range, 4-41 months). Based on clinical examination, goitre size at 4 months decreased more in the CBZ + T3 and CBZ + Triac groups than in the CBZ group (P = 0.02). The overall remission rate tended to be higher in the groups treated with CBZ + T3 and CBZ + Triac than in the group treated with CBZ alone, but the difference did not reach statistical significance (P = 0.17). No difference in the relapse rate was observed between the three groups. CONCLUSION: TSH suppression combined with CBZ has little or no effect on remission and relapse rates in Graves' disease patients.