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Endocrine Abstracts (2022) 81 P741 | DOI: 10.1530/endoabs.81.P741

ECE2022 Poster Presentations Thyroid (136 abstracts)

Efficacy of radioactive iodine treatment in Graves Disease using a calculated 131I dose and predictive factors of success in a Portuguese cohort

Sara Franco 1 , Rita Teixeira Ferreira 2 , Inês Cardoso Ferreira 2 , Ana Quítalo 1 , David Barbosa 1 , Maria Manuel Costa 1 , Henrique Vara Luiz 1 , Luisa Raimundo 1 & Ana Isabel Santos 2

1Hospital Garcia de Orta, Endocrinology, Portugal; 2Hospital Garcia de Orta, Nuclear Medicine, Portugal

Aim: Dose corrected for thyroid gland size is one of the methods used to determine radioactive iodine (RAI) activity for patients with Graves disease (GD). This study was aimed to investigate the real-world success rate of this method and the predictors of success after first treatment.

Methods: This is a retrospective study of 80 patients with GD treated between 2014 and 2020 in a tertiary referral hospital in Almada, Portugal. The successful group was defined as maintained Eu- or hypothyroid for at least 12 months after RAI therapy. We used SPSS and Excel to analyze the data.

Results: A total of 80 patients (67 females; mean age: 48 years (SD 13)) were selected and enrolled. The mean estimated thyroid gland size was 59.6 (SD 25) g. Out of 80 patients, 63 (79%) were successfully (Group 1) and 17 (21%) were unsuccessfully (Group 2) treated with the first dose of RAI. In Group 1, one year after the first dose of radioactive iodine therapy, 65% of patients were hypothyroid and 14% were euthyroid. The mean overall dose was 11.6 mCi (SD 4). Univariate analysis showed a significant association between shorter disease duration (P=0.031), lower T3 levels (P=0.017) and treatment success, but no significant association between sex, age, TRAb titres, RAIU, thyroid gland size, and previous anti-thyroid treatment. Multivariate logistic regression analysis failed to demonstrate a single independent factor capable of predicting RAI effectiveness, although some variables showed a tendency toward a statistical significance: shorter disease duration since the diagnosis (P=0.056) smaller RAI dose (P=0.05), and non-smoking (P=0.057). Nevertheless, we must consider these are only preliminary results, based on a relatively small sample. Further studies with larger samples are needed to confirm the results.

Conclusion: First RAI therapy using dose corrected for thyroid gland size had a success rate of 79% in patients with Graves disease, which is in line with previous studies. We found that shorter disease duration and lower T3 levels were strongly associated with treatment efficacy in the univariate analysis.

Volume 81

European Congress of Endocrinology 2022

Milan, Italy
21 May 2022 - 24 May 2022

European Society of Endocrinology 

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