Long-term outcome of Graves' disease patients treated in a region with iodine deficiency: relapse rate increases in years with thionamides.

Background: Graves' disease (GD) is an autoimmune disease affecting the thyroid gland and eyes and is treated with three therapeutic modalities. This prospective study was designed to find out the outcome of patients with GD treated with thionamides, radioactive iodine (RAI) or surgery in an iodine deficient region.
Materials and Methods: Fifty-six nonsmoking patients (mean age 38.9 +/- 13.7 years) with GD were enrolled and followed for a mean period of four years. They were analyzed with respect to their treatment options and their outcome.
Results: Remission rate by thionamides was 74.4% in the first year but decreased to 65.1% in the following four years (p=0.0001). Remission rate achieved in the second year did not predict long-term remission with thionamides. Long-term remission rates for RAI and surgery were 100% during about seven years of follow-up. These remission rates for RAI and surgery were reached in the first year and did not reveal a statistically significant change in the following years. Thyroidectomy, both subtotal and total, was carried out without any complication. Graves' ophthalmopathy emergence and progression were not found to be correlated with the preferred therapeutic modality of thyrotoxicosis.
Conclusion: Long-term thionamide therapy offered a relatively low rate of long-term remission in a region with iodine deficiency. Two years of remission achieved by thionamides did not predict long-term remission in patients living in iodine-deficient areas. RAI and thyroidectomy in experienced hands proved to be better therapeutic alternatives that can be carried out safely.