Aim: The aim of the study was the evaluation of the TSHRAb level changes and the comparison with thyroid function in patients with Graves disease treated with 131I 10 years ago.
Material and methods: The study has been conducted in 67 patients (57 women, 10 men) aged 2772 y (mean 48 years) with Graves disease.
All patients were treated with 131I due to hyperthyroidism confirmed by fT3, fT4 and TSH examination before treatment. Before therapy and after 10 years of follow-up, TSHRAb levels were measured according to radioreceptor method (TRAK Assay, BRAHMS Diagnostika GmbH). Ten years after 131I therapy TSH levels with IRMA method have been estimated.
Results: The levels of TSHRAb ranged from 1.3405 U/l (mean 62.66±107.37 U/l) before therapy. In 18 patients (26.9%) the levels were negative, in 5 subjects (7.5%) uncertain, in 44 patients (65.6%) positive. Ten years after 131I therapy, the determined TSH levels ranged between 0.04 and 41.82 mIU/l (mean 5.44±7.7 mIU/l) 49 subjects with hypothyroidism, 17 euthyroidism, 1 hyperthyroidism. The levels of TSHRAb ranged between 2.2 and 48.4 U/l (mean 7.66±7.74 U/l). In 59 patients (88.1%) the levels were negative, 1 person (1.5%) uncertain (this person was diagnosed as hyperthyreosis), 7 persons (10.4%) positive (6 hypothyreosis, 1 euthyreosis). In 2 patients (3%) the increase of the TSHRAb levels has been recorded, in 16 persons (23.9%) the antibody levels did not change, however in 49 patients (73.1%) were decreased.
Conclusions: The obtained results have pointed out the prominent (nine times) and statistically significant (P< 0.0001), reduction of TSHRAb levels in a long-term (10 years) follow-up. A long-term 131I therapy induces hypothyroidism requiring permanent systematic substitutive therapy.
25 - 29 Apr 2009
European Society of Endocrinology