Single and multiple factors analysis of the therapeutic effect in 131I treatment of Graves’ disease in elderly

Objectives To study the factors influencing therapeutic effect of 131I in treating Graves disease in elderly.

Methods All the 278 patients over 60 years old with Graves’hyperthyroidism who received 131I therapy between 2006 and 2011 were intensively followed up, among which, 220(mean age 65.35±5.00 years,including 50 males and 150 females)were successfully followed up. Curative effects of all patients were judged only in a single visit.Each patient was evaluated once for therapeutic efficacy. The assessment of the therapeutic effect was made according to cure (including hypothyroidism)and not-cured(including improvement and ineffectiveness) after 131I therapy. According to the calculation formula of 131I dose and clinical experience, the factors that may affect efficacy of 131I therapy were determined, including age, sex, thyroid weight, disease duration, severity of disease, course of ATD treatment,total dose of 131I, 24h RAIU. 220 patients were divided into 5 groups according to the follow-up time, Chi-square test was used to analyze the curative effect with 131I therapy of the 5 groups. Stepwise logistic regression was used to analyze the influencing factors of efficacy with 131I therapy.

Results 1. After more than 1 years ,72.7% of the cases were cured, 25.4%were improved, and 1.8% were unchanged. 2. The results of multivariate analysis showed that the age of patients, the weight of thyroid, 24h-RAIU, and the giving 131I dosage/g thyroid tissue were correlated to not-cured. The logistic regression equation was statistically significant.

Conclusions 1. Radioactive 131I is a very effective treatment method for Graves' disease in elderly patient. 2. In older patients and those patients whose thyroid weight is bigger than 60g, 24h-RAIU is higher, the given 131I dose per gram tissue of thyroid should be increased,in order to increase the curative ratio.