ABSTRACT
To evaluate the response rate of hyperthyroidism to radioactive iodine treatment [RAI] and the mortality rate post RAI treatment in a Qatari cohort the records were analyzed retrospectively of 113 hyperthyroid Qatari patients [23 male, 90 female] treated with RAI [I-131] in the Endocrine Clinic, Hamad Medical Corporation, between 1984 and 2002. 90[79.6%] had diffuse goiter, 14[12.4%] multinodular goiter, 6 [5.3%] single nodular goiter amid 3 [2.7%] unknown etiology. Follow up ranged from two to ten years with free thyroxin and thyroid stimulating hormone being recorded at diagnosis; six months and one year post RAI treatment amid yearly thereafter. The incidence of hypothyroidism was 64.4% after six months post RAI treatment and 75.9% at one year. Euthyroid state was high in patients who did not receive antithyroid drugs, whereas the hypothyroid state was higher in a group with pre-treatment antithyroid medication [80% versus 62.8%]. The euthyroid state was more in diffuse hyperthyroidism 22.4%, while 84.6% of multinodular goiter became hypothyroid after six months of RAI treatment. Mortality rate was not increased post RAI treatment as compared to general population. Time incidence of hypothyroidism was 75.9% at one-year post RAI treatment amid time rate of hypothyroidism increased with the length of follow up to 10 years [86.7%]. There was no linear relation in response rate to increasing doses of RAI treatment groups