Radioiodine therapy of Graves’ disease at Ibadan - The first seven years

Objectives The study aims at assessing the efficacy of radioiodine I-131 therapy (RAI) as a recently introduced treatment option of hyperthyroidism in Nigeria.

Methods A retrospective follow-up study of all patients who had been treated with empirical RAI for Graves’ disease from August 2006 to September 2013 at the Thyroid Clinic of the department. Cure following RAI was defined as euthyroidism or hypothyroidism, while recalcitrant hyperthyroidism referred to persistent hyperthyroidism following RAI.

Results 43 patients were included in the study, with a female preponderance observed (83.7%). The modal age group was 50-59 years. Most patients were recalcitrant to antithyroid medication (ATDs)), as 31 (72.1%) were hyperthyroid at presentation despite the fact that most patients (90.7%) were on ATDs. The range of administered RAI was 336.7-743.7 MBq. Twenty-six patients (60.5%) achieved cure, while 5 (11.6%) remained hyperthyroid, and 12 (27.9%) returned to sources of referral or defaulted follow-up. Fourteen patients (32.6%) had thyroid-associated ophthalmopathy (TAO). Factors favoring cure were female gender (chi square p= 0.001), age equalling or exceeding 50 years (p=0.035). A tendency to cure was observed in the absence of TAO, prior thyroidectomy, and with hyperthyroid rather than euthyroid status at presentation. However, this latter set of associations was not statistically significant. Previous treatment with carbimazole did not influence outcome of therapy (p=0.78).

Conclusions Radioiodine therapy remains a viable treatment option for Graves' disease in Nigeria. The cure rate of 60.5% is an encouraging finding regarding efficacy of RAI. Our findings suggest that, in order to improve cure rate, attention should be given to patients of male gender, with TAO, and those presenting with recurrent goiters.