Outcome of Graves ‘ disease after Anti-thyroid Drug treatment in South West of Iran

Objective: This study was conducted to observe the optimal results of long term treatment with antithyroid drugs in patients with graves´ disease. Methodology: Total of 268 patients with graves´ disease who were referred to endocrinology clinic during 2005 – 2008 and treated with anti-thyroid drugs for a long term were studied. Data about the age, gender, estimated weight of thyroid before and after the treatment, level of thyroid hormones, disease relapse, hypothyroidism and the drug side–effects were collected and analyzed. Results: Eighty two (31%) patients were males, 186 (69%) females, mean age of 35±27 years and follow–up course of 31±16 months], were studied. After the discontinuation of long term treatment, 53% were affected with relapse of hyperthyroidism. The mean duration of hyperthyroidism relapse after the treatment was 8.3±7.3 months. The relapse rate was significantly higher in the treated patients in both ends of age spectrum (P 0.001). In males and patients with large thyroid and lower TSH level at the end of treatment, the rate of relapse was higher (P=0.016, P 0.033, P=0.001 respectively). The incidence of hypothyroidism after treatment was about 6%. More decrease of thyroid size during the treatment course, higher level of serum TSH after discontinuation of the treatment, and lower thyroid hormone levels before the treatment were some of the effective factors in hypothyroidism incidence (P=0.005, P 0.001, P 0.05 respectively). Of the 268 graves´ patients treated with antithyroid drugs, 104 patients (39%) remained euthyroid in the follow–up course. Conclusion: Using long–term treatment with antithyroid drugs is still the first step in treating patients with graves´ especially in middle–aged women with smaller goiters.