RESUMO
OBJECTIVE: The relapse rate of Graves' hyperthyroidism after finishing an antithyroid cicle is high. The objective of this work was to prospectively investigate the relapse rate of Graves' hyperthyroidism (GH) in patients with maintenance of a low dose of antithyroid drug (ATD) therapy. PATIENTS AND METHOD: From March 1997, all patients with GH consecutively attending the same center who remained euthyroid with low doses of synthetic ATD (carbimazole or methimazole: 2.5-5mg/day) on 2 consecutive follow-up visits (at 10-12 months) were included in this study. Instead of withdrawing ATD, the aim was to continue with this low dose for a 5-year period (group M: 53 patients). From March 1997, data were also collected from patients with GH who were consecutively followed-up and who, meeting the criteria for inclusion in group M, had stopped receiving ATD before the start of the study (March 1997) (group R: 31 patients). MAIN OUTCOME: GH relapse was observed in 12/53 patients in group M (22.64%) and in 24/31 patients in group R (77.42%) (p<0.000). CONCLUSIONS: The GH relapse rate was significantly lower with long-term maintenance of a low dose of ATD than with therapy withdrawal.