Radioactive iodine therapy in Graves' hyperthyroidism: a prospective study from a tertiary referral centre in north India.

ABSTRACT

BACKGROUND: Radioactive iodine has gained widespread acceptance as the first-line therapy for Graves' hyperthyroidism and is the preferred treatment option in most situations. OBJECTIVE: A prospective study was conducted to look at the therapeutic practice of use of radioactive iodine in the treatment of Graves' hyperthyroidism, to determine whether the expected or desired therapeutic outcome is achieved. SETTINGS A tertiary referral centre in north India, Delhi that caters to patients with thyroid disorders. METHODS: One hundred and seventy four consecutive subjects with Graves' hyperthyroidism, who were given radioactive iodine were followed up. RESULTS: There were 59 (33.9%) males and 115 (66.1%) females. The mean age was 41.8 +/- 9 years. The dose of radioactive iodine ranged from 2 mCi to 15 mCi and the mean dose administered was 5.2 +/- 1.9 mCi. After one year following radioactive iodine therapy, 29 (16.7%) subjects were euthyroid, 51 (29.3%) were hypothyroid and the remaining 94 (54%) had persisting hyperthyroidism. Those subjects with persisting hyperthyroidism at one year after radioactive iodine had received a significantly lower dose compared to the groups who had achieved cure (either euthyroidism or hypothyroidism). CONCLUSION: The study shows that the current practice of empirical low dose radioactive iodine therapy to avoid hypothyroidism results in majority of patients having persisting hyperthyroidism. There is a need to take a new look at the current practice to increase the cure rate.