Graves' Orbitopathy Activation after Radioactive Iodine Therapy with and without Steroid Prophylaxis

Context: The reactivation of Graves' orbitopathy (GO) after radioiodine (RAI) for Graves' disease (GD) is a known effect, and its clinical relevance is controversial. Prevention of RAI-induced GO activation is possible in at-risk patients with oral glucocorticoids (OGC). Objectives: The aim of the study was to analyze the effects of RAI on GO with or without prophylactic steroids based on known risk factors and to compare the effectiveness of prophylaxis with iv glucocorticoids (IVGC) and OGC. Design: We conducted a retrospective study in which patients were assessed before and 1-12 months after RAI. Patients and Setting: Atotal of 113 patients were included in the study; 83 underwent RAI without prophylactic steroids for the absence of risk of activation, and 30 were treated with either GC(n = 21) or IVGC (n = 9). Main Outcome Measures: We analyzed the prevalence of GO activation with or without steroid prophylaxis and the difference in the prevalence of GO activation after OGC or IVGC. Results: GO activation was observed in 7.2% of patients without and 33.3% of patients with steroid prophylaxis (P < 0.0001), for an overall prevalence of 14.6%. GO activation occurred in 47.6% of patients treated with OGC but in none of the nine patients treated with IVGC (P = 0.0001). Disease activation was more prevalent in males (P < 0.02) and in older patients (P = 0.04) with a shorter duration of GD (P < 0.01) and time from GO onset (P < 0.01). Conclusions: GO may occur after RAI in approximately 15% of patients also in the absence of signs of active GO. Prophylactic OGC did not prevent GO activation in a large proportion of patients, compared to IVGC. (J Clin Endocrinol Metab 94: 3381-3386, 2009)