Predictive factors for early hypothyroidism following the radioactive iodine therapy in Graves\u2019 disease patients

Rui-Ting Hu,De-Shan Liu,Bin Li

doi:10.1186/s12902-020-00557-w

Abstract

BackgroundRadioactive iodine (RAI) therapy is an important treatment option for Graves’ disease (GD), the main side effect of RAI treatment is hypothyroidism, and the factors resulting in hypothyroidism are still controversial. The purpose of this retrospective study was to clarify the possible risk factors of early hypothyroidism after RAI therapy in Graves’ disease.MethodsWe reviewed 312 GD patients treated with RAI between January 2017 to December 2018, collected the potential risk factors, and analyzed the relationship between these variables and early hypothyroidism.ResultsAfter 6 months’ follow-up, 218 (69.87%) patients were evaluated as early hypothyroid. Male gender, shorter duration of disease, smaller thyroid weight, lower 2-h radioactive iodine uptake (RAIU), 6-h RAIU, 24-h RAIU and 6/24-h uptake ratio, lower administered dosages were significantly associated with early hypothyroidism. Logistics regression analysis showed that male gender, smaller thyroid weight and lower 6-h RAIU were associated with early hypothyroidism. Multi-factors combined ROC curve analysis suggested that the predictive power of male gender, smaller thyroid weight and lower 6-h RAIU for early hypothyroidism was 0.711.ConclusionsOur results show that RAI is an effective therapy for GD and most of the cured patients became to hypothyroid within 6 months. Male gender, smaller thyroid weight and lower 6-h RAIU are the main risk factors for early hypothyroidism.

Highlights

Radioactive iodine (RAI) therapy is an important treatment option for Graves’ disease (GD), the main side effect of RAI treatment is hypothyroidism, and the factors resulting in hypothyroidism are still controversial
The aim of this study is to examine the occur of early hypothyroidism in GD patients treated with RAI in our center between January 2017 to December 2018, and to identify the significant risk factors influencing the occurrence of early hypothyroidism
The following risk factors were collected and analyzed, including gender, age, duration of disease, weight of thyroid, anti-thyroid drugs (ATD) therapy history, Free triiodothyronine (FT3), Free thyroxine (FT4), TSH, TSH receptor antibody (TRAb), thyroperoxidase antibody (TPOAb), 2-h radioactive iodine uptake (RAIU), 6-h RAIU, 24-h RAIU, 6/24-h uptake ratio and the administered dosages according to the calculated dosage method

Summary

Introduction

Radioactive iodine (RAI) therapy is an important treatment option for Graves’ disease (GD), the main side effect of RAI treatment is hypothyroidism, and the factors resulting in hypothyroidism are still controversial. The purpose of this retrospective study was to clarify the possible risk factors of early hypothyroidism after RAI therapy in Graves’ disease. GD can be treated by anti-thyroid drugs (ATD), radioactive iodine (RAI) or thyroidectomy [4, 5]. ATD have lower risk of permanent hypothyroidism compared to RAI or thyroidectomy, but they are likely to cause frequently mild side effects and some rare but severe side effects, such as rash, vasculitis, agranulocytosis and acute hepatonecrosis, so the patients taking medications requires frequent hematological examinations [6]. After 12–18 months’ drug treatment, the risk of

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