Failure of the TRH test to predict the clinical course of patients in remission after antithyroid drug therapy for Graves' disease.

In an attempt to assess the predictive value of the TRH test in patients in remission after stopping antithyroid drugs for thyrotoxicosis, 11 euthyroid patients with a subnormal (group I) and 23 euthyroid patients with a normal serum TSH response to TRH (group II) were followed-up for one year. The mean +/- SE intervals since the withdrawal of drug therapy were 23.2 +/- 1.6 and 20.4 +/- 0.7 months, respectively, at the outset of the study. Five patients (45%) from group I and 7 patients (30%) from group II relapsed during the period of observation. In addition, a change from a subnormal TSH response to TRH and vice versa occurred in some patients. It is not possible to predict by means of the TRH test the subsequent clinical course of patients in remission following antithyroid drug therapy.