# Radioactive iodine therapy outcomes in young adults with Graves disease: a bi-center observational study

## TL;DR

This study examines how well radioactive iodine therapy works in young adults with Graves disease and finds that larger thyroid size and longer disease duration increase the risk of treatment failure.

## Contribution

The study identifies thyroid mass and treatment delay as novel predictors of radioactive iodine therapy outcomes in young Graves disease patients.

## Key findings

- The overall therapy success rate was 60.7% in young adults with Graves disease.
- Thyroid mass greater than 38 g and treatment delay of more than one year were significant risk factors for therapy failure.

## Abstract

To evaluate the efficacy of radioactive iodine therapy and to identify
determinants of treatment outcomes in young adults with Graves disease.

This retrospective cohort study analyzed young adults with Graves disease who
underwent radioactive iodine therapy at two tertiary medical centers in
Southwest China. Patients were stratified into two groups based on therapy
outcomes at 6 months post-radioactive iodine therapy: euthyroidism or
hypothyroidism (therapy success) and persistent hyperthyroidism
necessitating either a second radioactive iodine therapy or continuation of
anti-thyroid drug therapy (therapy failure). Multivariate logistic
regression and receiver operating characteristic curve analyses were
employed to assess predictive factors for treatment outcome.

A cohort of 163 young adults with Graves disease, with a mean age of 18 years
(range: 6 to 20 years) were included. The overall therapy success rate was
60.7%. Multivariate regression analysis identified that thyroid mass (OR
1.013, 95%CI 1.002 - 1.025; p-value = 0.022) and interval between diagnosis
and radioactive iodine therapy (> 1 year; OR 2.471, 95%CI 1.128 - 5.415;
p-value = 0.024) were risk factors associated with therapy failure. ROC
curve analysis identified 38 g as the optimal thyroid mass cutoff for
predicting treatment failure, demonstrating a sensitivity of 69% and
specificity of 70%. The positive and negative predictive values were 60% and
78%, respectively.

A therapy success rate of 60.7% was observed in radioactive iodine therapy in
young adults with Graves disease. Larger thyroid volume and prolonged
disease duration emerged as significant risk factor for therapy failure.