# Sex‐Related Differences in Risk Factors Associated With Nonhealing or Recurrence of Hyperthyroidism in Patients With Graves' Disease Treated With Radioactive Iodine

## TL;DR

This study finds that age, thyroid volume, and FT4 levels affect treatment outcomes differently in men and women with Graves' disease treated with radioactive iodine.

## Contribution

The study identifies sex-specific risk factors for nonhealing or recurrence of hyperthyroidism after radioactive iodine treatment in Graves' disease.

## Key findings

- Age and thyroid volume are independent risk factors for NHRH in female patients.
- Only FT4 is independently associated with NHRH in male patients.

## Abstract

To evaluate sex‐related differences in the risk factors associated with nonhealing or recurrence of hyperthyroidism (NHRH) in patients with Graves' disease (GD) treated with radioactive iodine.

In total, 285 patients were enrolled. Data on radioactive iodine (RAI) dosage, ultrasound indexes of the thyroid, and other clinical factors were collected. Patients were divided into NHRH and non‐NHRH (hypothyroidism or euthyroidism) groups based on treatment outcomes. Univariate and multivariate weighted logistic regression analyses were used to identify factors associated with NHRH. Sex‐specific analyses of these risk factors were also conducted.

There were no significant differences between the two groups in terms of sex, thyroid shear wave elastography velocity values, or pretreatment serum free thyroxine (FT4) levels. Thyroid volume and age were independently associated with NHRH, with the odds of NHRH gradually decreasing as age increased. In subgroup analyses, both age and thyroid volume were independent risk factors for NHRH in female patients (p < 0.05), while in male patients, only FT4 was independently associated with NHRH (p < 0.05).

In patients of different sexes, the influence of thyroid volume, age, and FT4 on treatment outcomes exhibits distinct patterns.

Age and thyroid volume were independent risk factors for the occurrence of nonhealing or recurrence of hyperthyroidism (NHRH) in female patients. Only free thyroxine (FT4) was independently associated with the occurrence of NHRH in male patients.