Analyzing the therapeutic effects of radioiodine-131 in patients with Graves disease by Cox's proportional hazard regression model

Objectives To analyze the factors related to therapeutic effects of ¹³¹I in patients with Graves disease (GD).

Methods 3946 patients with GD (2670 females, 1276 males, average age 41.12±10.94 yrs) treated with ¹³¹I from 1959 to 2007 were followed up with minimum of 3 ms, a maximum of 37.4 yrs, and an average 4.15±4.36 yrs. The terminal events of ¹³¹I therapy were divided into recovery, improvement, relapse and hypothyroidism. Cox’s proportional hazard regression model was used to perform univariate analyses for categorical variables, and to identify significant factors related to the four terminal events respectively.

Results Recovery: The protective factors were weight of thyroid, species of caplendus ATD, and the hazardous factors involved dosage of ¹³¹I and texture with dosage indicating the largest influence. Improvement: The protective factors included thyroid weight, time of caplendus ATD, and the hazardous factors reflected dosage and frequency of ¹³¹I with frequency being the largest influence. Hypothyroidism: The hazardous factors involved dosage of ¹³¹I, species and time of caplendus ATD, and the protective factors demonstrated gender, 24-th ¹³¹I uptake with dosage sharing the largest influence. Relapse: The hazardous factors reflected the course of the disease, cure history of preradiotherapy, thyroid weight, ATD species and frequency. And the protective factors were dosage of ¹³¹I with treatment history before radiotherapy having the largest influence.

Conclusions ¹³¹I therapy is a relative ideal treatment for GD, but the influence of factors related to its outcomes should be considered.