Endocrinol Metab.  2022 Dec;37(6):861-869. 10.3803/EnM.2022.1476.

Efficacy and Safety of Long-Term Methimazole versus Radioactive Iodine in the Treatment of Toxic Multinodular Goiter

• Azizi F
• Saadat N
• Takyar MA
• Abdi H
• Mehran L
• Amouzegar A

• KMID: 2537287
• DOI: http://doi.org/10.3803/EnM.2022.1476

Abstract

Background
This study compared the degree of sustained control of hyperthyroidism in patients with toxic multinodular goiter (TMNG) treated with long-term methimazole (LT-MMI) or radioactive iodine (RAI).
Methods
In this clinical trial, 130 untreated patients with TMNG were randomized to either LT-MMI or RAI treatment. Both groups were followed for 108 to 148 months, with median follow-up durations of 120 and 132 months in the LT-MMI and RAI groups, respectively. Both groups of patients were followed every 1 to 3 months in the first year and every 6 months thereafter.
Results
After excluding patients in whom the treatment modality was changed and those who were lost to follow-up, 53 patients in the LT-MMI group and 54 in the RAI group completed the study. At the end of the study period, 50 (96%) and 25 (46%) patients were euthyroid, and two (4%) and 25 (46%) were hypothyroid in LT-MMI and RAI groups, respectively. In the RAI group, four (8%) patients had subclinical hyperthyroidism. The mean time to euthyroidism was 4.3±1.3 months in LT-MMI patients and 16.3± 15.0 months in RAI recipients (P<0.001). Patients treated with LT-MMI spent 95.8%±5.9% of the 12-year study period in a euthyroid state, whereas this proportion was 72.4%±14.8% in the RAI-treated patients (P<0.001). No major treatment-related adverse events were observed in either group.
Conclusion
In patients with TMNG, LT-MMI therapy is superior to RAI treatment, as shown by the earlier achievement of euthyroidism and the longer duration of sustained normal serum thyrotropin.

Keyword

Hyperthyroidism; Antithyroid; Methimazole; Iodine radioisotopes; Follow-up; Thyrotropin

Figure

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  Fig. 1. Study population flow diagram.

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  Fig. 2. Time to euthyroidism in patients with toxic nodular goiter who received long-term methimazole versus radioactive iodine treatment (P<0.001). The horizontal line denotes the mean number of months to achieve euthyroidism in each study group.

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