[Individual outcome monitoring of TSH receptor antibody level for predicting the prognosis of Graves' disease].

AIM

This retrospective study is intended to provide further information on the controversially discussed ability of a Thyrotropin Receptor Antibody (TRAb) monitoring for predicting the outcome of Graves' disease.

METHOD

The study is based on 1480 blood samples of 346 patients (292 female, 54 male; age among 9 and 91 years) suffering from Graves' disease. A comparison between the TRAb levels and the serum free thyroid hormones as well as the basal thyrotropin was performed in the entire collective, in the group of non-treated patients and in 182 individual courses.

RESULTS

Even in comparable states of function, the individual TRAb levels were quite divergent. In the group with persistent dysfunction, they initially varied between 6 and 482 U/l (normal range < 15 U/l). A global evaluation of the particular groups hence did not show any correlation between the functional disorder and the respective TRAb levels. However, when considering the individual courses, a distinct dependence upon the development of the TRAb could be observed. As the limit for separating the group suffering from persistent malfunction or recurrence and the collective in remission, a decline of the individual TRAb level below 50% of the initial value has proven to be most suitable. This was observed in 94% of all remissions. In 90% of all relapsed patients, we either found persistent high TRAb levels (i.e. a maximum decrease down to 50% of the initial value) or another increase of the TRAb levels. The positive and negative predictive values of the method are 97% and 58%, respectively.

CONCLUSION

The outcome of Graves' disease depends on the individual changes of the TRAb levels rather than on their absolute values. In case of persistent TRAb, you have to expect a continuing dysfunction or a recurrence.