The usefulness of thyroid size and TSH receptor antibody (TRAb) determinations in predicting the effectiveness of tiamazole and I-131 treatment for Graves-Basedow's disease.

The aim of the study was to assess the usefulness of determining the thyroid size, TRAb level and their correlation as markers for predicting the effectiveness of conservative treatment in Graves-Basedow's disease. The study included 100 patients with Graves-Basedow's disease; group I treated with thiamazole, group II treated with 131I. The biggest thyroid size, x -42.09+/-13.94ml, was found in the group unsuccessfully treated with thiamazole and was statistically significant compared to that in the euthyreosis group, x -31.65+/-11.74ml (p<0.01) and controls x -14.45+/-2.37ml (p<0.001). It is noteworthy that the initial TRAb level in the group with persistent hyperthyroidism was higher (x -54.39+/-31.21 U/I) than that in the euthyreosis group (x -29.13+/-19.44 U/I) and controls (x -2.75+/-2.06 U/l), p<0.001 for both parameters. Elevated antibody levels were also found after 12 and 18 months of treatment. Moreover, in the 131 I patients, the biggest thyroid size before iodine administration was found in the group with persistent hyperthyroidism, x -56.56+/-24.19 ml. It was statistically significantly different compared to the thyroid size in the euthyreosis patients x -37.922+/-20.69 ml (p<0.001) and in the hypothyreosis patients, x -43.47+/-18.09 ml (p<0.05). Before 131I administration, the highest antibody levels were observed in the group with persistent hyperthyroidism, x -103.61+/-43.90 U/I (p<0.001) compared to euthyreosis, hypothyreosis and control groups. The significance of differences in TRAb levels in the examined groups was still observed 18 months after 131I administration. In the groups of patients treated with thyreostatics and radioactive iodine, the positive correlation between the thyroid size and TRAb level was found before as well as 12 and 18 months after the onset of treatment.1.The TRAb levels and thyroid sizes are important parameters that should be considered in predicting the effectiveness of treatment. 2. The TRAb level correlates with the thyroid size.