Ablative Versus Conservative Approach for Hyperthyroidism Treatment in Patients with Graves' Orbitopathy: A Retrospective Cohort Study

Background: Treatment for Graves’ hyperthyroidism (GH) in patients with Graves’ orbitopathy (GO) remains a topic of debate. This study aimed to investigate the outcome of GO following glucocorticoids, depending on the chosen thyroid treatment. Methods: This retrospective cohort study included 49 consecutive patients with GH and moderate-to-severe, active GO, as defined by the European Group on Graves' Orbitopathy guidelines. Twenty-four patients were treated with radioactive iodine (RAI) and 25 with methimazole (MMI). All patients were administered intravenous methylprednisolone. Follow-up visits occurred at weeks 24, 48, and 72. The primary endpoint was the overall outcome of GO at week 24. Response was defined as a change in at least two of the following eye features: reduction ≥1 point in clinical activity score; proptosis reduction ≥2 mm; eyelid aperture reduction ≥2 mm; increase in eye ductions ≥8 degrees. Results: Follow-up duration was 72 weeks for both groups (interquartile range 66-72 for RAI and 48-72 for MMI). The proportion of responders for week 24 overall GO outcome was greater in RAI (54.1% vs. 16%; odds ratio [OR] 6.2 [confidence interval (CI): 1.6-23.6], p = 0.0075), but it increased in MMI at weeks 48 and 72, with no differences between groups. There was a trend indicating a better response in RAI regarding individual eye features. Improvement in GO-specific quality of life questionnaire at week 24 was trendily more pronounced in RAI (responders 50% vs. 28% in MMI; OR = 2.5 [CI: 0.7-8.4], p = 0.11), although results were similar in both groups at later time points. At week 24, only one patient (4%) in RAI and three (12%) in MMI experienced worsening of GO. Fifty-nine adverse events were recorded among 36 patients, with no differences between groups, except for infections, which were more frequent in RAI (53.8% vs. 15.3% in MMI; OR = 6.41 [CI: 1.7-23.9], p = 0.0056). Conclusions: RAI appears to be associated with an earlier response of GO to intravenous glucocorticoids. In the long term, a conservative approach also seems to be effective. RAI appears to be relatively safe when patients are concurrently treated with glucocorticoids. However, randomized clinical trials are necessary to confirm these findings.