Topic: RADIOIODINE TREATMENT FOR HYPERTHYROIDISM

Results: Patients given a single dose of I of 600 MBq (16 mCi) (N = 485) had a higher cure rate (84.1%) compared with those receiving either 370 MBq (10 mCi) (74.9%, P < 0.001) or those given 185 MBq (5 mCi) (63%, P < 0.001). An increased incidence of hypothyroidism by 1 year was evident with higher doses (600 MBq: 60.4%; 370 MBq: 49.2%, P = 0.001; 185 MBq: 38.1%, P < 0.001). Binary logistic regression analysis identified a 600 MBq dose of (131)I [adjusted odds ratio, AOR: 3.33; P <0.001], female gender [AOR: 1.75; P = 0.002], lower presenting serum free T4 concentration [AOR: 1.01; P <0.001] and absence of a palpable goitre [AOR: 3.33; P <0.001] to be independent predictors of cure. Similarly, a 600 MBq dose [AOR: 3.79; P <0.001], female gender [AOR: 1.46; P = 0.02], younger age [AOR: 1.03; P <0.001], absence of a palpable goitre [AOR: 3.85; P <0.001] and presence of ophthalmopathy [AOR: 1.57; P = 0.02] were identified as independent factors predicting the probability of development of hypothyroidism at one year. Based on these findings, formulae to indicate probability of cure and risk of hypothyroidism for application to individual patients were derived.