Influence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational study

Inorganic iodine has long been used as a treatment for Graves’ disease. It is currently a treatment option for mild Graves’ disease, but there have been no data suggesting the validity of continuing low-dose iodine treatment after improvement in thyrotoxicosis. For this prospective observational stu...

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Main Authors: Hiroki Takizawa, Toyoyoshi Uchida, Nami Suzuki, Hiroyuki Onose, Emiko Yamada, Koshi Hashimoto, Natsuko Watanabe, Yuya Nishida, Hirotaka Watada
Format: Article
Language:English
Published: The Japan Endocrine Society 2025-06-01
Series:Endocrine Journal
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Online Access:https://www.jstage.jst.go.jp/article/endocrj/72/6/72_EJ24-0575/_html/-char/en
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author Hiroki Takizawa
Toyoyoshi Uchida
Nami Suzuki
Hiroyuki Onose
Emiko Yamada
Koshi Hashimoto
Natsuko Watanabe
Yuya Nishida
Hirotaka Watada
author_facet Hiroki Takizawa
Toyoyoshi Uchida
Nami Suzuki
Hiroyuki Onose
Emiko Yamada
Koshi Hashimoto
Natsuko Watanabe
Yuya Nishida
Hirotaka Watada
author_sort Hiroki Takizawa
collection DOAJ
description Inorganic iodine has long been used as a treatment for Graves’ disease. It is currently a treatment option for mild Graves’ disease, but there have been no data suggesting the validity of continuing low-dose iodine treatment after improvement in thyrotoxicosis. For this prospective observational study, we recruited patients with Graves’ disease treated only with low-dose iodine (potassium iodine ≤25 mg/day). These patients were then divided into two groups: those who continued with low-dose iodine (C group) and those who discontinued it (DC) group. We compared the 2-year thyrotoxicosis relapse rate between the two groups and investigated anthropometric variables associated with relapse. Of 2,159 patients on iodine treatment, 56 patients met the selection criteria but 4 who gave consent dropped out, leaving 25 in the C group and 27 in the DC group. Regarding baseline characteristics, the C group had a longer duration of Graves’ disease, lower therapeutic iodine doses, and lower TSH levels than the DC group. During the 2-year follow-up period, the relapse rate in the C and DC groups was 32.0% and 22.2%, respectively (p = 0.536). Furthermore, patients who relapsed had significantly higher therapeutic iodine doses, FT4 levels, and TSAb levels at baseline than patients who did not relapse. Multiple logistic regression showed that relapse is positively associated with therapeutic iodine dose and TSAb levels. The present study failed to show the efficacy of continuing low-dose iodine in patients with Graves’ disease after improvement in thyrotoxicosis. The relapse rate seems to be affected by residual immune activity. UMIN000047660
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institution Kabale University
issn 1348-4540
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publishDate 2025-06-01
publisher The Japan Endocrine Society
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series Endocrine Journal
spelling doaj-art-0bfe314df5c4441b9dc033fef576c0f12025-08-20T03:55:27ZengThe Japan Endocrine SocietyEndocrine Journal1348-45402025-06-0172666367010.1507/endocrj.EJ24-0575endocrjInfluence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational studyHiroki Takizawa0Toyoyoshi Uchida1Nami Suzuki2Hiroyuki Onose3Emiko Yamada4Koshi Hashimoto5Natsuko Watanabe6Yuya Nishida7Hirotaka Watada8Department of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421, JapanDepartment of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421, JapanDepartment of Internal Medicine, Ito Hospital, Tokyo 150-8308, JapanKanaji Thyroid Hospital, Tokyo 114-0015, JapanKanaji Thyroid Hospital, Tokyo 114-0015, JapanDepartment of Diabetes, Endocrinology and Hematology, Dokkyo Medical University Saitama Medical Center, Saitama 343-0845, JapanDepartment of Internal Medicine, Ito Hospital, Tokyo 150-8308, JapanDepartment of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421, JapanDepartment of Metabolism & Endocrinology, Juntendo University Graduate School of Medicine, Tokyo 113-8421, JapanInorganic iodine has long been used as a treatment for Graves’ disease. It is currently a treatment option for mild Graves’ disease, but there have been no data suggesting the validity of continuing low-dose iodine treatment after improvement in thyrotoxicosis. For this prospective observational study, we recruited patients with Graves’ disease treated only with low-dose iodine (potassium iodine ≤25 mg/day). These patients were then divided into two groups: those who continued with low-dose iodine (C group) and those who discontinued it (DC) group. We compared the 2-year thyrotoxicosis relapse rate between the two groups and investigated anthropometric variables associated with relapse. Of 2,159 patients on iodine treatment, 56 patients met the selection criteria but 4 who gave consent dropped out, leaving 25 in the C group and 27 in the DC group. Regarding baseline characteristics, the C group had a longer duration of Graves’ disease, lower therapeutic iodine doses, and lower TSH levels than the DC group. During the 2-year follow-up period, the relapse rate in the C and DC groups was 32.0% and 22.2%, respectively (p = 0.536). Furthermore, patients who relapsed had significantly higher therapeutic iodine doses, FT4 levels, and TSAb levels at baseline than patients who did not relapse. Multiple logistic regression showed that relapse is positively associated with therapeutic iodine dose and TSAb levels. The present study failed to show the efficacy of continuing low-dose iodine in patients with Graves’ disease after improvement in thyrotoxicosis. The relapse rate seems to be affected by residual immune activity. UMIN000047660https://www.jstage.jst.go.jp/article/endocrj/72/6/72_EJ24-0575/_html/-char/engraves’ diseaseinorganic iodinerelapsethyrotropin receptor stimulating antibody
spellingShingle Hiroki Takizawa
Toyoyoshi Uchida
Nami Suzuki
Hiroyuki Onose
Emiko Yamada
Koshi Hashimoto
Natsuko Watanabe
Yuya Nishida
Hirotaka Watada
Influence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational study
Endocrine Journal
graves’ disease
inorganic iodine
relapse
thyrotropin receptor stimulating antibody
title Influence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational study
title_full Influence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational study
title_fullStr Influence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational study
title_full_unstemmed Influence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational study
title_short Influence of therapeutic inorganic iodine on long-term prognosis of Graves’ disease: a multicenter prospective observational study
title_sort influence of therapeutic inorganic iodine on long term prognosis of graves disease a multicenter prospective observational study
topic graves’ disease
inorganic iodine
relapse
thyrotropin receptor stimulating antibody
url https://www.jstage.jst.go.jp/article/endocrj/72/6/72_EJ24-0575/_html/-char/en
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