Predictors of the results of radioiodine therapy of Gagves’ disease

Abstract

The aim of this study was to investigate different clinical and laboratory predictors influence on radioiodine therapy results for Graves' disease. A 1-year prospective study was performed on 621 patients treated with empirical radioiodine therapy. Mean administered dose of 131I was 350 MBq. All patients were divided into two groups with small (<25 ml) and large (>25 ml) thyroid gland volume. One day before radioiodine therapy all patients were examined with fT4 measurement and radioiodine uptake test to determine percentage uptake at 2 h, 4 h, and 24 h after test dose of 131I administration. Unique universal method to estimate predictors influence for any classification task was presented and used for actual task of radioiodine therapy results estimation. For patients with small thyroid gland volume a set of 11 predictors that have an influence on therapy result was revealed and importance of each predictor from indicated set was determined. The most influential predictors were administered dose of 131I, thyroid gland volume, percentage uptake at 24 h after test dose of 131I administration, and patient age. For patients with large thyroid gland volume a set of 10 predictors was revealed. The most influential predictors were administered dose of 131I, thyroid gland volume, percentage uptake at 2 h after test dose of 131I administration, and patient age. Accounting all predictors from indicated sets for both patient groups allows constructing of classification system that provides therapy result estimation for any patient and any administered dose of 131I with accuracy above 90%.